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Indirect and selling expenses

$ 1,229,162

$ 1,185,097

$ 1,132,232

Direct costs

771,725

745,137

694,436

Operating costs and expenses

346,440

328,048

329,159

Depreciation and amortization

17,691

16,638

16,222

Amortization of intangible assets

10,888

12,481

17,184

Total operating costs and expenses

375,019

357,167

362,565

Operating income

82,418

82,793

75,231

Interest expense

(8,553)

(9,470)

(10,072)

Other income (expense)

121

1,184

(1,559)

Income before income taxes

73,986

74,507

63,600

Provision for income taxes

11,110

27,923

24,231

$ 62,876

$ 46,584

$ 39,369

Earnings per share:

$ 3.35

$ 2.45

$ 2.04

Weighted-average common shares outstanding:

$ 3.27

$ 2.40

$ 2.00

18,766,000

18,989,000

19,335,000

Other comprehensive income (loss), net of tax

19,244,000

19,416,000

19,663,000

^[1]

$ 4,601

$ (2,149)

$ (5,010)

Comprehensive income, net of tax

$ 67,477

$ 44,435

$ 34,359

[1]	Net of tax of $1.0 million, $2.2 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Consolidated Statements of Stockholders' Equity - USD ($)
shares in Thousands, $ in Thousands

Total

Common Stock

Additional Paid-in Capital

Retained Earnings

Treasury Stock

Accumulated Other Comprehensive Loss

Balance at Dec. 31, 2014

$ 500,689

$ 21

$ 267,206

$ 285,937

$ (49,994)

$ (2,481)

Balance (in shares) at Dec. 31, 2014

19,430

1,606

Other comprehensive income (loss)

39,369

(5,010)

^[1]

(5,010)

Equity compensation

10,850

10,392

$ 458

Exercise of stock options

932

Exercise of stock options (in shares)

Issuance of shares pursuant to vesting of restricted stock units

234

Net payments for stock issuances and buybacks

(24,861)

276

$ (25,137)

Net payments for stock issuances and buybacks (in shares)

(676)

676

Tax impact of stock option exercises and award vesting

1,307

Balance at Dec. 31, 2015

523,276

$ 21

280,113

325,306

$ (74,673)

(7,491)

Balance (in shares) at Dec. 31, 2015

19,032

2,282

Other comprehensive income (loss)

46,584

(2,149)

^[1]

(2,149)

Equity compensation

9,082

8,734

$ 348

Exercise of stock options

3,034

$ 1

3,033

Exercise of stock options (in shares)

128

Issuance of shares pursuant to vesting of restricted stock units

221

Net payments for stock issuances and buybacks

(13,823)

547

$ (14,370)

Net payments for stock issuances and buybacks (in shares)

(360)

360

Balance at Dec. 31, 2016

566,004

$ 22

292,427

371,890

$ (88,695)

(9,640)

Balance (in shares) at Dec. 31, 2016

19,021

2,642

Other comprehensive income (loss)

62,876

4,601

^[1]

4,601

Equity compensation

10,291

9,985

$ 306

Exercise of stock options

4,722

Exercise of stock options (in shares)

176

Issuance of shares pursuant to vesting of restricted stock units

180

Net payments for stock issuances and buybacks

(32,464)

687

$ (33,151)

Net payments for stock issuances and buybacks (in shares)

(715)

715

Balance at Dec. 31, 2017

$ 616,030

$ 22

$ 307,821

$ 434,766

$ (121,540)

$ (5,039)

Balance (in shares) at Dec. 31, 2017

18,662

3,357

[1]	Net of tax of $1.0 million, $2.2 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net income	$ 62,876	$ 46,584	$ 39,369
Adjustments to reconcile net income to net cash provided by operating activities:
Bad debt expense	1,480	1,089	268
Deferred income taxes	(7,390)	6,535	2,106
Non-cash equity compensation	10,291	9,082	10,850
Depreciation and amortization	28,579	29,119	33,406
Deferred rent	(177)	(43)	1,002
Proceeds from hedge sale		3,600
Facilities consolidation reserve	1,479
Amortization of debt issuance costs	673	532	532
Other adjustments, net	275	(1,169)	1,254
Changes in operating assets and liabilities, net of the effect of acquisitions:
Contract receivables	(7,234)	(29,020)	(2,713)
Prepaid expenses and other assets	(1,844)	(2,792)	(170)
Accounts payable	3,631	8,941	(2,374)
Accrued salaries and benefits	5,597	1,140	(13,208)
Accrued expenses and other current liabilities	13,257	10,252	(4,522)
Deferred revenue	8,341	(707)	2,367
Income tax receivable and payable	(5,697)	(2,447)	8,356
Other liabilities	3,054	(639)	(320)
Net Cash Provided by Operating Activities	117,191	80,057	76,203
Cash Flows from Investing Activities
Capital expenditures for property and equipment and capitalized software	(14,513)	(13,791)	(12,682)
Payments for business acquisitions, net of cash received	(91)	(100)	(1,818)
Net Cash Used in Investing Activities	(14,604)	(13,891)	(14,500)
Cash Flows from Financing Activities
Advances from working capital facilities	590,225	478,584	381,745
Payments on working capital facilities	(643,363)	(530,728)	(420,265)
Payments on capital expenditure obligations	(4,808)	(4,041)	(3,289)
Debt issue costs	(1,612)		(17)
Proceeds from exercise of options	4,722	3,034	932
Tax benefits of stock option exercises and award vesting			1,307
Net payments for stockholder issuances and buybacks	(32,464)	(13,823)	(24,861)
Net Cash Used in Financing Activities	(87,300)	(66,974)	(64,448)
Effect of Exchange Rate Changes on Cash, Cash Equivalents, and Restricted Cash	1,094	(416)	(1,746)
Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash	16,381	(1,224)	(4,491)
Cash, Cash Equivalents, and Restricted Cash, Beginning of Period	7,885	9,109	13,600
Cash, Cash Equivalents, and Restricted Cash, End of Period	24,266	7,885	9,109
Supplemental disclosure of cash flow information:
Interest	7,922	8,937	9,845
Income taxes	$ 21,659	$ 21,094	16,315
Non-cash investing and financing transactions:
Capital expenditure obligations			$ 12,870

Basis of Presentation and Nature of Operations	12 Months Ended
Basis of Presentation and Nature of Operations	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Nature of Operations	NOTE 1—BASIS OF PRESENTATION AND NATURE OF OPERATIONS Basis of Presentation and Nature of Operations The accompanying consolidated financial statements include the accounts of ICF International, Inc. (“ICFI”) and its subsidiary, ICF Consulting Group, Inc. (“Consulting,” and together with ICFI, “the Company”), and have been prepared in accordance with U.S. generally accepted accounting principles. Consulting is a wholly owned subsidiary of ICFI. ICFI is a holding company with no operations or assets other than its investment in the common stock of Consulting. All other subsidiaries of the Company are wholly owned by Consulting. All significant intercompany transactions and balances have been eliminated. Nature of Operations The Company provides professional services and technology-based solutions to government and commercial clients, including management, technology, and policy consulting and implementation services, in the areas of energy, environment, and infrastructure; health, education, and social programs; safety and security; and consumer and financial. The Company offers a full range of services to these clients throughout the entire life cycle of a policy, program, project, or initiative, from research and analysis and assessment and advice to design and implementation of programs and technology-based solutions, and the provision of engagement services and programs. The Company’s major clients are United States (“U.S.”) federal government departments and agencies, most significantly the Department of Health and Human Services, Department of State and Department of Defense. The Company also serves U.S. state and local government departments and agencies, international governments, and commercial clients worldwide. Commercial clients include airlines, airports, electric and gas utilities, oil companies, banks and other financial services companies, transportation, travel and hospitality firms, non-profits/associations, law firms, manufacturing firms, retail chains, and distribution companies. The term “federal” or “federal government” refers to the U.S. federal government, and “state and local” or “state and local government” refers to U.S. state and local governments, unless otherwise indicated. The Company, incorporated in Delaware, is headquartered in Fairfax, Virginia. It maintains offices throughout the world, including over 59 offices in the U.S. and more than 23 offices in key markets outside the U.S., including offices in the United Kingdom, Belgium, China, India and Canada. Reclassifications Certain immaterial amounts in the 2016 and 2015 consolidated financial statements have been reclassified to conform to the current year presentation. To be consistent with the Company’s current presentation, the Company reclassified $4.3 million of amounts related to deferred compensation liabilities from accrued salaries and benefits to long-term as of December 31, 2016.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies

NOTE 2—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and contingent liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from those estimates.

Revenue Recognition

The Company recognizes revenue when persuasive evidence of an arrangement exists, services have been rendered, the contract price is fixed or determinable, and collectability is reasonably assured. The Company enters into three types of contracts: time-and-materials, cost-based, and fixed-price.

•

Time-and-Materials Contracts. Revenue for time-and-materials contracts is recorded on the basis of labor hours worked multiplied by the contract-defined billing rates, plus the costs of other items used in the performance of the contract. Profits and losses on time-and-materials contracts result from the difference between the cost of services performed and the contract-defined billing rates for these services.

•

Cost-Based Contracts. Revenue under cost-based contracts is recognized as costs are incurred. Applicable estimated profit, if any, is included in earnings in the proportion that incurred costs bear to total estimated costs. Incentives, award fees, or penalties related to performance are also considered in estimating revenue and profit based on actual and anticipated awards, taking into consideration factors such as the Company’s prior award experience and communications with the customer regarding performance.

•

Fixed-Price Contracts. Revenue for fixed-price contracts is recognized when earned, generally as work is performed. Services performed vary from contract to contract and are not always uniformly performed over the term of the arrangement. The Company recognizes revenue in a number of different ways on fixed-price contracts based on the nature of the services to be provided and an assessment of which method best mirrors the pattern of performance for the deliverable/contract, including:

•

Proportional Performance: Revenue on certain fixed-price contracts is recognized based on proportional performance when the provision of services extends beyond an accounting period with more than one discrete performance act, and progress towards completion can be measured based on a reliable output or input. Under this method, revenue is recorded each period based on certain contract performance input measures incurred (labor hours, labor costs, or total costs) or output measures completed, expressed as a proportion of a total project estimate. Progress on a contract is monitored regularly to ensure that revenue recognized reflects project status. When hours or costs incurred are used as the basis for revenue recognition, the hours or costs incurred represent a reasonable surrogate for output measures of contract performance, including the presentation of deliverables to the client. Clients are obligated to pay as services are performed, and, in the event that a client cancels the contract, payment for services performed through the date of cancellation is typically negotiated with the client.

•

Specific Performance: When the services to be performed consist of a single act, revenue is recognized at the time the act is performed or at the completion of the single service.

•

Straight-Line: When services are performed or are expected to be performed consistently throughout an arrangement, or when the Company is compensated on a retainer or fixed-fee basis, revenue is recognized ratably over the period benefited.

•

Completed Contract: Revenue and costs on certain fixed-price contracts are recognized at completion if the final act is so significant to the arrangement that value is deemed to be transferred only at completion.

Revenue recognition requires the Company to use judgment relative to assessing risks, estimating contract revenue and costs or other variables, and making assumptions for scheduling and technical issues. Due to the size and nature of many of the Company’s contracts, the estimation of revenue and the cost to perform for contracts in process can be complicated and subject to many variables. Contract costs include labor, subcontractor costs, and other direct costs, as well as an allocation of indirect costs. At times, the Company must also make assumptions regarding the length of time to complete the contract because costs include expected increases in wages, prices for subcontractors, and other direct costs. From time to time, the Company obtains new information which causes it to revise its estimated total costs or hours to fulfill contract requirements and thus the associated revenue earned on a contract. To the extent that a revised estimate affects contract profit or revenue previously recognized, the Company records the cumulative effect of the revision in the period in which the facts requiring the revision become known. A provision for the full amount of an anticipated loss on any type of contract is recognized in the period in which the anticipated loss becomes probable and can be reasonably estimated. As a result, operating results could be affected by revisions to prior accounting estimates.

Contractual arrangements are evaluated to assess whether revenue should be recognized on a gross versus net basis. Management’s assessment when determining gross versus net revenue recognition is based on several factors, such as whether the Company serves as the primary service provider, has autonomy in selecting subcontractors, or has credit risk, all of which are primary indicators that the Company serves as the principal to the transaction. In such cases, revenue is recognized on a gross basis. When such indicators are not present and the Company is primarily functioning as an agent under an arrangement, revenue is recognized on a net basis, being limited to fees earned for facilitating the transaction.

Payments to the Company on cost-based contracts with the U.S. federal government are provisional payments subject to audit and adjustment by the government. Indirect costs applied to government contracts are also subject to audit and adjustment and such audits have been finalized only through December 31, 2007. Contract revenue has been recorded in amounts that are expected to be realized on final audit and settlement of costs.

The Company prepares client invoices in accordance with the terms of the applicable contract, and billing terms may not be directly related to the performance of services. Unbilled receivables are invoiced based on the achievement of specific events as defined by each contract, including deliverables, timetables, and incurrence of certain costs. Unbilled receivables are classified as a current asset. Advanced billings to clients in excess of revenue earned are recorded as deferred revenue until the revenue recognition criteria are met. Reimbursements of out-of-pocket expenses are included in revenue when the corresponding costs are included in the cost of revenue. The Company records revenue net of taxes collected from clients when the taxes are to be remitted to governmental authorities.

The Company may proceed with work based on client direction prior to the completion and signing of formal contract documents. The Company has a review process for approving any such work. Revenue associated with such work is recognized only when it can be reliably estimated and realization is probable. The Company bases its estimates on a variety of factors, including previous experiences with the client, communications with the client regarding contract status, and its knowledge of the likelihood that contractual limits, or funding, will be increased.

Cash and Cash Equivalents

The Company considers cash on deposit and all highly liquid investments with original maturities of three months or less when purchased to be cash and cash equivalents.

Restricted Cash

The Company has restricted cash representing amounts held in escrow accounts and/or not readily available due to contractual restrictions.

Allowance for Doubtful Accounts

The Company considers a number of factors in its estimate of allowance for doubtful accounts, including the customer’s financial condition, historical collection experience, and other factors that may bear on collectability of the receivables. The Company writes off contract receivables when such amounts are determined to be uncollectible.

Property and Equipment

Property and equipment are carried at cost and are depreciated using the straight-line method over their estimated useful lives, which range from two to seven years. Leasehold improvements are amortized on a straight-line basis over the shorter of the economic life of the improvement or the related lease term.

Goodwill and Other Intangible Assets

The purchase price of an acquired business is allocated to the tangible assets and separately identifiable intangible assets acquired, less liabilities assumed, based on their respective fair values, with the excess recorded as goodwill. Goodwill represents the excess of costs over the fair value of net assets of businesses acquired. Goodwill and intangible assets acquired in a business combination and determined to have an indefinite useful life are not amortized, but instead are reviewed for impairment annually, or more frequently if impairment indicators arise. Intangible assets with estimable useful lives are amortized over such lives and reviewed for impairment if impairment indicators arise.

Impairment

The Company has historically performed its annual goodwill impairment test as of September 30 of each year. Effective for the annual goodwill impairment test for 2017, the Company performed the required annual test as of October 1. During the fourth quarter of 2017, the Company early adopted the Accounting Standards Update 2017-04, Intangibles—Goodwill and Other (Topic 350) (ASU 2017-04) issued by the Financial Accounting Standards Board (the “FASB”). ASU 2017-04 simplified the calculation and recognition of impairment of goodwill if there is evidence of an impairment based on qualitative or quantitative assessments by eliminating Step 2 of the two step impairment test required by the prior accounting standard.

For the purposes of performing the annual goodwill impairment test, the Company has one reporting unit. For the goodwill impairment test as of October 1, 2017, the Company opted to perform a qualitative assessment of whether it is more likely than not that its reporting unit's fair value is less than its carrying amount. If, after completing its qualitative assessment, the Company determines that it is more likely than not that the estimated fair value of the reporting unit exceeded its carrying amount, it may conclude that no impairment exists. If the Company concludes otherwise, a goodwill impairment test must be performed, which includes a comparison of the reporting unit’s fair value to the carrying amount and recognizing as an impairment loss the difference of the reporting unit’s fair value and the carrying amount of goodwill.

The Company’s qualitative analysis as of October 1, 2017 included macroeconomic, industry and market specific considerations, financial performance indicators and measurements, and other factors. Based on this qualitative assessment, the Company determined that it is more likely than not that the fair value of its reporting unit exceeded its carrying amount, and thus the impairment test was not required to be performed. Therefore, based on management’s review, a goodwill impairment loss was not required for 2017. Historically, the Company has not recorded any goodwill impairment losses.

The Company is required to review long-lived assets and certain identifiable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset might not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds its fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less cost to sell.

Capitalized Software

The Company capitalizes eligible costs to develop enhancements and upgrades to internal-use software that are incurred subsequent to the preliminary project stage. Amortization expense is recorded on a straight-line basis over the expected economic life of the software, typically lasting three to five years. During the years ended December 31, 2017, 2016, and 2015, the costs capitalized for the development of internal-use software were not material to the Company’s consolidated financial statements.

Deferred Rent

The Company recognizes rent expense on a straight-line basis over the non-cancellable term of each lease, including renewal option periods when renewal is reasonably assured or executed. Lease incentives or abatements received at or near the inception of leases are accrued and amortized ratably over the life of the lease.

Stock-based Compensation

The Company recognizes stock-based compensation expense related to share-based payments to employees, including grants of employee stock options, restricted stock awards, restricted stock units (“RSUs”), and cash-settled restricted stock units (“CSRSUs”) on a straight-line basis over the requisite service period, which is generally the vesting period. The Company recognizes expense for performance-based share awards (“PSAs”), which have both a performance and condition, on a straight-line basis over the three-year performance period. Non-employee director awards, which do not include vesting conditions, are for board-related services and therefore expensed when earned.

Stock-based compensation expense is based on the estimated fair value of the instruments on award and the estimated number of shares the Company ultimately expects will vest. The Company estimates the rate of future forfeitures based on factors such as historical experience and employee class. In addition, the estimation of PSAs that will ultimately vest requires judgment based on the performance and market conditions that will be achieved over the performance period. Changes to these estimates are recorded as a cumulative adjustment in the period estimates are revised.

The fair value of stock options, restricted stock awards, RSUs, PSAs, and non-employee director awards is estimated based on the fair value of a share of common stock at the grant date. The Company has elected to use the Black-Scholes-Merton option pricing model to determine the fair value of stock options. The fair value of PSAs is estimated using a Monte Carlo simulation model.

CSRSUs are settled only in cash payments. The cash payment is based on the fair value of the Company’s stock price at the vesting date, calculated by multiplying the number of CSRSUs vested by the Company’s closing stock price on the vesting date, subject to a maximum payment cap and a minimum payment floor. The Company treats these awards as liability-classified awards, and, therefore, accounts for them at fair value estimated based on the closing price of the Company’s stock at the reporting date.

Other Comprehensive Income (Loss)

Other comprehensive income (loss) represents foreign currency translation adjustments arising from the use of differing exchange rates from period to period and the gain on the sale of an interest rate hedge agreement. The financial positions and results of operations of the Company’s foreign subsidiaries are based on the local currency as the functional currency and are translated to U.S. dollars for financial reporting purposes. Assets and liabilities of the subsidiaries are translated at the exchange rate in effect at each balance sheet date. Income statement accounts are translated at the average rate of exchange prevailing during the period. Translation adjustments are reported in accumulated other comprehensive loss included in stockholders’ equity in the Company’s consolidated balance sheets. The activity included in other comprehensive income (loss), net of tax, in the Company’s consolidated statements of comprehensive income for each period reported is summarized below.

	Year ended December 31,
	2017			2016			2015
Foreign currency translation adjustments	$	4,177		$	(4,321	)	$	(5,676	)
Foreign currency realized losses reclassified into earnings		—			(3	)		666
Change in fair value of derivative designated as cash flow hedge		441			—			—
Gain on sale of interest rate hedging agreement, net of tax⁽¹⁾		(17	)		2,175			—
Other comprehensive income (loss), net of tax⁽²⁾	$	4,601		$	(2,149	)	$	(5,010	)

⁽¹⁾

On December 1, 2016, the Company sold the interest rate hedge agreement. The fair value of the interest rate hedge was recorded in other comprehensive income (loss), net of tax, and will be reclassified to earnings when earnings are impacted by the cash flows of the hedged items, the interest payments on the Credit Facility or its replacement from January 31, 2018 to January 31, 2023. See additional details on the hedge agreement in Note 9—Derivative Instruments and Hedging Activities.

⁽²⁾	Net of tax of $1.0 million, $2.2 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Derivative Instruments

Derivative instruments designated as cash flow hedges are recorded on the consolidated balance sheet at fair value as of the reporting date, and the effective portion of the hedge is recorded in other comprehensive income (loss) on the consolidated statement of comprehensive income and reclassified to earnings in the period that the hedged instruments affect earnings. Management reviews the effectiveness of the hedges on a quarterly basis.

Income Taxes

The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The Company evaluates its ability to benefit from all deferred tax assets and establishes valuation allowances for amounts it believes will more likely than not be unrealizable. For uncertain tax positions, the Company uses a more-likely-than-not recognition threshold based on the technical merits of the income tax position taken. Income tax positions that meet the more-likely-than-not recognition threshold are measured in order to determine the tax benefit recognized in the financial statements. Penalties, if probable and reasonably estimable, and interest expense related to uncertain tax positions are not recognized as a component of income tax expense but recorded separately in indirect expenses and interest expense, respectively.

Treasury Shares

Treasury shares are accounted for under the cost method.

Segment, Customer and Geographic Information

The Company operates in one segment based on the consolidated information used by its chief operating decision maker in evaluating the financial performance of its business and allocating resources. This single segment represents the Company’s core business which is providing professional services for government and commercial clients. Although, in order to provide insight into the breadth of its capabilities and diversity of its client base, the Company describes its clients’ four key market areas and evaluates its revenue based on the type of client served, the Company does not manage its business or allocate resources based on those service offerings or types of clients.

Approximately $550.3 million, $563.0 million, and $540.0 million of the Company’s revenue for the years 2017, 2016, and 2015, respectively, was derived under prime contracts and subcontracts with agencies and departments of the federal government representing 45%, 48%, and 48% of total revenue, respectively. No other customer accounted for 10% or more of the Company’s revenue during the years ended 2017, 2016, and 2015, respectively.

The Company’s international operations provide services to both commercial and international government clients. Revenue is attributed to a particular geographic area based on the administrative location of the client that awarded the contract. The Company’s revenue generated from international clients as a percentage of total revenue was approximately 9%, 10%, and 11% for the years 2017, 2016, and 2015, respectively.

At December 31, 2017 and 2016, long-lived assets held internationally were not material.

Risks and Uncertainties

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and contract receivables. The majority of the Company’s cash transactions are processed through one U.S. commercial bank. Cash held domestically in excess of daily requirements is used to reduce any amounts outstanding under the Company’s Credit Facility. As of December 31, 2017 and 2016, the Company held approximately $10.4 million and $5.4 million, respectively, of cash in foreign bank accounts. To date, the Company has not incurred losses related to cash and cash equivalents.

The Company’s contract receivables consist principally of receivables from agencies and departments of, as well as from prime contractors to, the U.S. federal, state and local, and international governments, as well as from commercial organizations. The Company believes that this credit risk with respect to federal and other governments, including when the Company is a subcontractor to a prime contractor, is limited due to the credit worthiness of the respective governmental entity. Receivables from commercial clients generally pose a greater credit risk than those from government agencies and departments, and, as a result, are subject to ongoing monitoring. The Company extends credit in the normal course of operations and does not require collateral from its clients.

The Company has historically been, and continues to be, heavily dependent on contracts with the federal government and is subject to audit, in particular, by agencies of the federal government. Such audits determine, among other things, whether an adjustment of invoices rendered to the government is appropriate under the underlying terms of the contracts. Management does not expect any significant adjustments as a result of government audits that will adversely affect the Company’s financial position.

Recent Accounting Pronouncements

Recent Accounting Pronouncements Adopted

Cash Receipts and Cash Payments

In August 2016, FASB issued Accounting Standard Update (“ASU”) 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments that addressed eight specific cash flow issues to reduce the existing diversity in practice. During the third quarter of 2017, the Company elected to early adopt ASU 2016-15, which did not have a material impact on the Company’s consolidated financial statements.

Restricted Cash

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force), which requires entities to show the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between cash and cash equivalents and restricted cash and cash equivalents in the statement of cash flows. During the third quarter of 2017, the Company elected to early adopt ASU 2016-18 retrospectively, with adjustments to the 2016 and 2015 fiscal years’ consolidated statements of cash flows. The impact of the adoption on the Company’s previously reported consolidated statements of cash flows is summarized as follows:

	Year Ended December 31, 2016						Year Ended December 31, 2015
	As Reported			As Adjusted			As Reported			As Adjusted
Restricted cash	$	(494	)	$	—		$	116		$	—
Net Cash Provided by Operating Activities		79,563			80,057			76,319			76,203
Effect of exchange rate changes on cash		(403	)		(416	)		(1,746	)		(1,746	)
(Decrease) Increase in Cash and Cash Equivalents		(1,705	)		—			(4,375	)		—
Increase in Cash, Cash Equivalents, and Restricted Cash		—			(1,224	)		—			(4,491	)
Cash and Cash Equivalents, Beginning Period		7,747			—			12,122			—
Cash, Cash Equivalents, and Restricted Cash, Beginning Period		—			9,109			—			13,600
Cash and Cash Equivalents, End of Period		6,042			—			7,747			—
Cash, Cash Equivalents, and Restricted Cash, End of Period		—			7,885			—			9,109

Goodwill

In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other (Topic 350) (ASU 2017-04), which simplifies the measurement of goodwill during the execution of a goodwill impairment test in the event that there is evidence of an impairment based on qualitative or quantitative assessments. ASU 2017-04 does not change how the goodwill impairment is identified, and the Company will continue to perform a qualitative assessment annually to determine whether the two-step impairment test is required. The previous accounting standard required the impairment loss to be recognized under Step 2 of the impairment test. This required the Company to determine whether the carrying amount of the reporting unit’s goodwill exceeds its implied fair value. The implied fair value was calculated by assigning the fair value of the reporting unit to all of its assets and liabilities as if it had been acquired in a business combination. The new standard requires the Company to determine the fair value of the reporting unit and subtract the carrying amount from the fair value of the reporting unit to determine if there is any impairment. If the Company concludes that an impairment exists, an impairment loss will be recorded reflecting the difference of the reporting unit’s estimated fair value over its carrying amount. During the fourth quarter of 2017, the Company elected to early adopt ASU 2017-04, which did not have a material impact on the Company’s consolidated financial statements.

Derivative and Hedging

In August 2017, the FASB issued ASU 2017-12: Derivatives and Hedging (Topic 815) (ASU 2017-12). ASU 2017-12’s objective is to improve the financial reporting of an entity’s hedges and better aligns an entity’s hedge accounting with the entity’s risk management strategies, as well as simplify the current hedge accounting guidance. During the fourth quarter of 2017, the Company elected to early adopt ASU 2017-12, which did not have a material impact on the Company’s consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

Revenue Recognition

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). ASU 2014-09 provides a single comprehensive revenue recognition framework and supersedes existing revenue recognition guidance. Included in the new principles-based revenue recognition model are changes to the basis for determining the timing for revenue recognition. In addition, the standard expands and improves revenue disclosures. In August 2015, the FASB issued ASU 2015-14 to amend ASU 2014-09 in order to defer the effective date of the new standard. In accordance with this update, the Company elected to adopt the requirements of the new standard effective January 1, 2018.

The Company has evaluated the impact of the new guidance on the timing of revenue and expanded disclosure requirements. The Company has concluded that, for the majority of its contracts, there is no material change in the timing of revenue recognition. However, the new standard will result in a change in revenue timing for performance incentives under certain contracts. Under the prior guidance, performance incentives were recognized as revenue when specific quantitative goals were achieved, generally at the end of a measurement period. Under the new standard, these incentives are considered variable consideration and the Company will include in revenue the most likely amount of the priced incentives to be earned as contract work is performed and recognize revenue associated with the incentives over the term of the agreement. This change is not expected to result in a material change to the Company’s annual revenue since most incentives have a one-year measurement period which is aligned with the Company’s fiscal year, but the change may accelerate revenue recognized on a quarterly basis.

As of January 1, 2018, the Company adopted the standard using the modified retrospective transition method. Under the modified retrospective method, the new standard applies to new contracts and those that were not completed as of January 1, 2018. For those contracts not completed as of January 1, 2018, the Company is finalizing the catch-up adjustment to retained earnings but does not expect the transition adjustment to be material to the consolidated financial statements. Total net cash provided by operating activities and net cash used by investing and financing activities will not be impacted by the adoption of the new standard. Prior periods will not be retrospectively adjusted, but the Company will maintain dual reporting for the year of initial application in order to disclose the effect on revenue of adopting the new guidance. Additional disclosures under the new standard will, among other required disclosures, disaggregate revenue into categories that reflect how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors.

Leases

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). This update revises an entity’s accounting for operating leases and requires lessees to recognize a right-of-use asset and lease liability for all leases with terms of more than 12 months. This update also requires that lessees recognize assets and liabilities on the balance sheet for the rights and obligations created by all such leases and requires disclosures designed to give financial statement users information on the amount and timing of lease expenses arising from such leases. These disclosures include certain qualitative and specific quantitative disclosures. For lessees, the new guidance is not expected to significantly change the recognition, measurement, and presentation of expenses arising from a lease. This update is effective for the first interim and annual periods beginning after December 15, 2018, with early adoption permitted. The Company continues to evaluate the impact of adopting ASU 2016-02, the elections to be made at adoption in a modified retrospective approach, the impact of future modifications to the new accounting pronouncement, our inventory of operating leases, the software options that will aid in the implementation and accounting under the new accounting pronouncement, and the timing of adoption.

Accumulated other comprehensive loss

In February 2018, the FASB issued ASU 2018-02: Income Statement – Reporting Comprehensive Income (Topic 220) (ASU 2018-02). ASU 2018-02’s objective is to address the application of ASC 740 to certain provisions of the new tax reform legislation commonly known as Tax Cuts and Jobs Act (the “Tax Act”). ASC 740 requires the effect of a change in tax rates on deferred assets and liabilities be included in income from continuing operations in the reporting period that contains the enactment date of the change. The guidance applies even in situations in which the tax effects were initially recognized directly in other comprehensive income at the previous rate, resulting in a stranded amount in accumulated other comprehensive income (loss) (AOCI) related to the income tax rate differential. ASU 2018-02 requires the Company to reclassify the amount of stranded taxes in AOCI to retained earnings. This update is effective for fiscal years beginning after December 15, 2018, including interim periods therein, and early adoption is permitted. The Company is currently evaluating the impact of the pronouncement on the consolidated financial statements.

Contract Receivables

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Contract Receivables

NOTE 3—CONTRACT RECEIVABLES

Contract receivables, net of the established allowance, are stated at amounts expected to be realized in future periods. Unbilled receivables result from revenue that has been earned but cannot be billed yet under the terms of the contract. Unbilled receivables can be invoiced at contractually defined intervals or milestones, as well as on completion of the contract or government audits. The Company anticipates that the majority of unbilled receivables will be substantially billed and collected within one year, and therefore, classifies them as current assets in accordance with industry practice.

Contract receivables consisted of the following at December 31:

	2017			2016
Billed	$	169,027		$	168,012
Unbilled		117,037			108,432
Retainages		6,160			5,088
Other		3,144			2,424
Allowance for doubtful accounts		(3,853	)		(2,591	)
Contract receivables, net	$	291,515		$	281,365

Property Plant And Equipment [Abstract]

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Property and Equipment

12 Months Ended

Dec. 31, 2017

Property and Equipment

NOTE 4—PROPERTY AND EQUIPMENT

Property and equipment consisted of the following at December 31:

	2017			2016
Leasehold improvements	$	18,873		$	17,847
Software		42,835			41,269
Furniture and equipment		26,076			26,570
Computers		28,826			28,874
		116,610			114,560
Accumulated depreciation and amortization		(78,558	)		(74,076	)
Total property and equipment, net	$	38,052		$	40,484

Depreciation and amortization expense for the years ended December 31, 2017, 2016, and 2015, was approximately $17.7 million, $16.6 million, and $16.2 million, respectively.

Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

NOTE 5—GOODWILL AND OTHER INTANGIBLE ASSETS

Goodwill

The changes in the carrying amount of goodwill for the fiscal years ended December 31 were as follows:

	2017		2016
Balance as of January 1	$	683,683	$	687,404
Goodwill resulting from the Trade NTE business combination		—		191
Goodwill resulting from the Mostra business combination		—		654
Goodwill resulting from the Olson business combination		—		267
Effect of foreign currency translation		2,425		(4,833	)
Total goodwill	$	686,108	$	683,683

Other Intangible Assets

Intangible assets with definite lives are primarily amortized over periods ranging from approximately 4 to 10 years. The weighted-average period of amortization for all intangible assets as of December 31, 2017 is 9.1 years. The customer-related intangible assets, which consist of customer contracts, backlog, and non-contractual customer relationships, are being amortized based on estimated cash flows and respective estimated economic benefit of the assets. The weighted-average period of amortization of the customer-related intangibles is 9.1 years. Intangible assets related to developed technology are being amortized on an accelerated basis over a weighted-average period of 5.5 years. Intangible assets with an indefinite life consist of a domain name.

Other intangibles consisted of the following at December 31:

	2017
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value
Customer-related	$	84,878	$	(49,782	)	$	35,096
Developed technology		1,463		(1,350	)		113
Total amortizable intangible assets		86,341		(51,132	)		35,209
Intangible with indefinite life		95		—			95
Total other intangible assets	$	86,436	$	(51,132	)	$	35,304

	2016
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value
Customer-related	$	115,806	$	(70,090	)	$	45,716
Developed technology		1,463		(1,145	)		318
Total amortizable intangible assets		117,269		(71,235	)		46,034
Intangible with indefinite life		95		—			95
Total other intangible assets	$	117,364	$	(71,235	)	$	46,129

Aggregate amortization expense for the years ended December 31, 2017, 2016, and 2015, was approximately $10.9 million, $12.5 million, and $17.2 million, respectively. The estimated future amortization expense relating to intangible assets is as follows:


Year ending December 31,
2018	$	8,441
2019		6,132
2020		4,532
2021		4,082
2022		4,125
Thereafter		7,897
Total	$	35,209

Accrued Salaries and Benefits

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Accrued Salaries and Benefits

12 Months Ended

Dec. 31, 2017

NOTE 6—ACCRUED SALARIES AND BENEFITS

Accrued salaries and benefits consisted of the following at December 31:

	2017		2016
Accrued paid time off and leave	$	11,904	$	11,342
Accrued salaries		9,343		9,443
Accrued bonuses, liability-classified awards and commissions		16,909		13,025
Accrued payroll taxes and withholdings		2,557		1,948
Accrued medical		3,720		3,026
Other		1,212		979
Total accrued salaries and benefits	$	45,645	$	39,763

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2017

Payables And Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

NOTE 7—ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

Accrued expenses and other current liabilities consisted of the following at December 31:

	2017		2016
Accrued subcontractor and other direct costs	$	47,508	$	30,153
Deposits		6,641		12,389
Accrued IT and software licensing costs		2,261		5,349
Accrued taxes and insurance premiums		1,963		1,306
Accrued lease exit and facilities costs		1,591		77
Accrued interest		705		841
Accrued professional services		1,131		795
Other accrued expenses and current liabilities		3,280		1,721
Total accrued expenses and other current liabilities	$	65,080	$	52,631

Long-Term Debt

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Long-Term Debt

NOTE 8—LONG-TERM DEBT

On May 17, 2017, the Company entered into a Fifth Amended and Restated Business Loan and Security Agreement with a syndication of 11 commercial banks (the “Credit Facility”). The Credit Facility: (i) includes modifications to the Company’s Fourth Amended and Restated Business Loan and Security Agreement, (ii) matures on May 17, 2022, (iii) increases the borrowing ceiling up to $600.0 million without a borrowing base requirement, taking into account financial, performance-based limitations, and (iv) provides for an “accordion,” which permits additional revolving credit commitments of up to $300.0 million, subject to lenders’ approval. While the modification of the Credit Facility did not increase the amount of outstanding, $106.0 million of funds from new syndicated borrowings was used to pay off or pay down borrowings from syndicate members prior to the loan modification and align the allocation of debt within the syndicate. These amounts were included within the “Advances from working capital facilities” and “Payments on working capital facilities” line items in the statement of cash flows for the year ended December 31, 2017.

The Company has the option to borrow funds under the Credit Facility at interest rates based on both LIBOR (1, 3, or 6 month rates) and the Base Rate, at its discretion, plus their applicable margins. Base Rates are fluctuating per annum rates of interest equal to the highest of (i) the Federal Funds Open Rate, plus 0.5%, (ii) the Prime Rate, and (iii) the daily LIBOR rate, plus a LIBOR Margin of between 1.00% and 2.00% based on our Leverage Ratio (as defined under the Credit Facility), 1.25% as of December 31, 2017. The interest accrued based on LIBOR rates is to be paid on the last business day of the interest period (1, 3, or 6 months), while interest accrued based on the Base Rates is to be paid in quarterly installments. The Credit Facility provides for letters of credit aggregating up to $60.0 million which reduce the funds available under the Credit Facility when issued. The Credit Facility is collateralized by substantially all of the assets of the Company and requires that the Company remain in compliance with certain financial and non-financial covenants. The financial covenants require, among other things, that the Company maintain at all times an Interest Coverage Ratio (as defined under the Credit Facility) of not less than 3.00 to 1.00 and a Leverage Ratio of not more than 3.75 to 1.00 (subject to adjustment, in certain circumstances) for each fiscal quarter. As of December 31, 2017, the Company was in compliance with its covenants under the Credit Facility.

The Credit Facility was subject to a commitment fee on the unused portion of the Credit Facility of between 0.13% and 0.25% per annum, based on our Leverage Ratio, 0.15% per annum at December 31, 2017 and 0.25% per annum at December 31, 2016.

As of December 31, 2017, the available borrowing capacity under the Credit Facility (excluding the accordion) was $390.0 million. Taking into account the financial and performance-based limitations, the available borrowing capacity (excluding the accordion) was $245.1 million as of December 31, 2017.

Long-term debt outstanding and the weighted average interest rate at December 31 is summarized as follows:

2017

2016

Debt Outstanding

Weighted Average

Interest Rate

Debt Outstanding

Weighted Average

Interest Rate

Revolving Line of Credit/Swing Line

206,250

2.65

259,389

2.46

Debt Issuance Cost

The Company’s debt issuance costs, which are included within other assets, are amortized over the term of indebtedness. Amortizable debt issuance costs were $6.9 million and $5.8 million as of December 31, 2017 and 2016, respectively. Accumulated amortization related to debt issuance costs were $4.7 million and $4.5 million, as of December 31, 2017 and 2016, respectively. Amortization expense of $0.7 million, $0.5 million, and $0.5 million was recorded for each of the years ended December 31, 2017, 2016, and 2015, respectively. The Company incurred $1.6 million in debt issuance costs for the year ended December 31, 2017.

Letters of Credit

At December 31, 2017 and 2016, the Company had twelve and nine outstanding letters of credit totaling approximately $3.7 million and $3.4 million, respectively. These letters of credit are renewed annually.

Derivative instruments and Hedges Activities	12 Months Ended
Derivative instruments and Hedges Activities	Dec. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative instruments and Hedges Activities	NOTE 9—DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES On August 31, 2017, the Company entered into a floating-to-fixed interest rate swap agreement for an aggregate notional amount of $25.0 million which hedged a portion of the Company’s floating rate indebtedness. The swap agreement requires the Company to pay a fixed rate of 1.8475% per annum plus the applicable margin pursuant to the Credit Facility. Notwithstanding the terms of the interest rate swap transaction, the Company is ultimately obligated for all amounts due and payable under the Credit Facility. The cash flows from the transaction begin August 31, 2018 and end on August 31, 2023. The Company has designated the swap as a cash flow hedge. On a quarterly basis, management evaluates the swap to determine its effectiveness or ineffectiveness. Management intends that the swap remain effective. Realized gains and losses in connection with each required interest payment will be reclassified from AOCI to interest expense. On September 30, 2016, the Company entered into a floating-to-fixed interest rate hedge agreement for an aggregate notional amount of $100.0 million which hedged a portion of the Company’s floating rate indebtedness. The cash flows from the interest rate swap agreement begin on January 31, 2018 and end on January 31, 2023. The Company designated the swap as a cash flow hedge. On December 1, 2016, the Company sold the interest rate hedge agreement. The fair value of the interest rate hedge, as of the date of the sale, was recorded in other comprehensive income, net of tax. The gain from the sale will be recognized into earnings when earnings are impacted by the cash flows of the previously hedged items, as interest payments are made on the Credit Facility from January 31, 2018 to January 31, 2023. As of December 31, 2017, the net amount of realized gains and losses from the hedge agreements expected to be reclassified from AOCI into earnings within the next 12 months is $0.7 million. The Company uses interest rate swap arrangements to manage or hedge its interest rate risk. The Company does not use such instruments for speculative or trading purposes.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

NOTE 10—INCOME TAXES

The domestic and foreign components of income before provision for income taxes are as follows for the years ended December 31:

	2017		2016		2015
Domestic	$	69,347	$	69,159	$	54,150
Foreign		4,639		5,348		9,450
Income before income taxes	$	73,986	$	74,507	$	63,600

Income tax expense consisted of the following for the years ended December 31:

	2017			2016			2015
Current:
Federal	$	12,995		$	12,979		$	14,797
State		3,243			3,514			2,669
Foreign		1,476			1,932			1,475
Total current		17,714			18,425			18,941
Deferred:
Federal		(9,425	)		8,872			4,562
State		2,749			1,222			512
Foreign		72			(596	)		216
Total deferred		(6,604	)		9,498			5,290
Income tax expense	$	11,110		$	27,923		$	24,231

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and income tax purposes.

Deferred tax assets (liabilities) consisted of the following at December 31:

	2017			2016
Deferred Tax Assets
Allowance for bad debt	$	1,003		$	1,008
Accrued paid time off		1,624			2,592
Accrued bonus		—			55
Foreign net operating loss (NOL) carry forward		1,301			1,371
Federal/state net operating loss (NOL) carry forward		507			3,010
Stock option compensation		2,726			4,292
Deferred rent		3,355			5,423
Deferred compensation		3,238			3,662
Foreign tax credits		505			2,631
State tax credits		1,785			1,784
Federal tax credits		—			225
Foreign exchange		2,051			5,349
Accrued liabilities and other		3,272			3,378
		21,367			34,780
Less: Valuation Allowance		(1,636	)		(1,131	)
Total Deferred Tax Assets		19,731			33,649

Deferred Tax Liabilities
Retention		(1,375	)		(1,684	)
Prepaid expenses		(1,045	)		(1,654	)
Payroll taxes		(489	)		(617	)
Unbilled revenue		(5,407	)		(8,728	)
Depreciation		(4,773	)		(6,664	)
Amortization		(39,993	)		(51,842	)
Deferred gain and other		—			(1,574	)
Total Deferred Tax Liabilities		(53,082	)		(72,763	)
Total Net Deferred Tax Liability	$	(33,351	)	$	(39,114	)

On December 20, 2017, the U.S. Congress passed the “Tax Cuts and Jobs Act” (the “Tax Act”), which was signed into law on December 22, 2017 and is generally effective beginning January 1, 2018. The Company will be impacted in several ways as a result of the Tax Act, including, but not limited to, provisions which include a permanent reduction in the U.S. federal corporate income tax rate from 35% to 21%, the revaluation of deferred tax assets and liabilities required as a result of the tax rate change and the application of a mandatory one-time “transition tax” on unremitted earnings of certain foreign subsidiaries that were previously tax deferred.

The Company has not completed the accounting for the tax effects of enactment of the Tax Act; however, in certain cases, as described below, the Company has made a provisional estimate of the effects on our existing deferred tax balances and the one-time transition tax. The Company has recognized the provisional estimate as a reduction in the provision for income taxes, which is included as a component of income tax expense from continuing operations.

The Company re-measured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. However, the Company is still analyzing certain aspects of the Tax Act and refining estimates, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. Pursuant to SAB 118, the provisional amount recorded related to the re-measurement of the deferred tax balances was a net tax benefit of $17.6 million.

The one-time “transition tax” is based on the Company’s total post-1986 earnings and profits (E&P) which the Company has previously deferred from US income taxation. Pursuant to SAB 118, the Company recorded a provisional estimate of approximately $1.4 million, net of related foreign tax credits, for the one-time transition tax liability for the Company’s foreign subsidiaries, resulting in an increase in income tax expense. The Company has not yet completed the calculation of the total post-1986 foreign E&P and related foreign tax pools for these foreign subsidiaries. Further, the transition tax is based in part on the amount of those earnings held in cash and other specified assets. This amount, as well as the related foreign tax credit utilization, may change when the Company finalizes the calculation of post-1986 foreign E&P and related foreign tax pools that were previously deferred from US federal taxation and once the Company finalizes the amounts held in cash or other specified assets. Similarly, our cumulative foreign tax credit carry forward balance as of December 31, 2017 and any valuation allowance required (as applicable) may also change. No additional income taxes have been provided for any remaining undistributed foreign earnings not subject to the transition tax and any additional outside basis difference inherent in these entities as these amounts continue to be permanently reinvested in foreign operations. The impact of the transition tax is a preliminary estimate and will not be finalized until the later part of 2018.

At both December 31, 2017 and 2016, the Company had net operating loss (“NOL”) carry-forwards for foreign income taxes of approximately $4.1 million and $4.1 million, respectively, all of which may be carried forward indefinitely.

At December 31, 2017, the Company had NOL carry-forwards for state income tax purposes of approximately $8.5 million, which expire in 2034. The Company acquired these NOLs as a result of its purchase of Olson in November 2014. Internal Revenue Code Section 382 imposes an annual limitation on the use of a corporation’s NOLs, tax credits and other carryovers after an “ownership change” occurs. Section 382 imposes an annual limitation on the amount of post-ownership change taxable income a corporation may offset with pre-ownership change NOLs and credits. In general, the annual limitation is determined by multiplying the value of the corporation’s stock immediately before the ownership change (subject to certain adjustments) by the applicable long-term tax-exempt rate. Any unused portion of the annual limitation is available for use in future years until such NOLs are scheduled to expire (in general, NOLs may be carried forward 20 years). The Company presently estimates that it will be able to fully utilize the remaining acquired NOLs prior to their expiration.

At December 31, 2017, the Company had gross state income tax credit carry-forwards of approximately $2.8 million, which expire between 2017 and 2026. A deferred tax asset of approximately $1.8 million (net of federal benefit) has been established related to these state income tax credit carry-forwards as of December 31, 2017.

The need to establish valuation allowances for deferred assets is based on a more-likely-than-not threshold that the benefit of such assets will be realized in future periods. Appropriate consideration has been given to all available evidence, including historical operating results, projections of taxable income, and tax planning alternatives. The Company concluded that a valuation allowance of approximately $1.1 million and $1.1 million was required for tax attributes related to specified foreign jurisdictions as of December 31, 2017 and 2016, respectively, and an additional $0.5 million valuation allowance was recorded against our US foreign tax credit carry forwards as a result of enactment of the Tax Act as of December 31, 2017. Due to the interplay of the “transition tax” referenced above and the utilization of foreign tax credits, the amount of valuation allowance recorded against our US foreign tax credit carry forwards as of December 31, 2017 is subject to change once the Company finalizes its calculations.

The total amount of unrecognized tax benefits as of December 31, 2017 and 2016, was $0.8 million and $1.2 million, respectively. Included in the balance as of December 31, 2017 and 2016, were $0.7 million and $1.0 million, respectively, of tax positions that, if recognized, would impact the effective tax rate.

The unrecognized tax benefit reconciliation, excluding penalty and interest, is as follows:

Unrecognized tax benefits at January 1, 2015	$	702
Decrease attributable to settlements		(174	)
Increase attributable to tax positions taken during a prior period		12
Decrease attributable to lapse of statute of limitations		(140	)
Unrecognized tax benefits at December 31, 2015	400
Increase attributable to tax positions taken during a prior period		925
Decrease attributable to lapse of statute of limitations		(140	)
Unrecognized tax benefits at December 31, 2016		1,185
Decrease attributable to lapse of statute of limitations		(365	)
Unrecognized tax benefits at December 31, 2017	$	820

The Company’s policy is not to recognize accrued interest and penalties related to unrecognized tax benefits as a component of tax expense. The Company had approximately $0.2 million and $0.2 million of accrued penalty and interest at December 31, 2017 and 2016, respectively.

The Company’s 2013 to 2016 tax years remain subject to examination by the Internal Revenue Service for federal tax purposes. Certain significant state and foreign tax jurisdictions are also either currently under examination or remain open under the statutes of limitation and subject to examination for the tax years from 2013 to 2016.

Although the Company believes it has adequately provided for all uncertain tax positions, amounts asserted by taxing authorities could be greater than the Company’s accrued position. Accordingly, additional provisions on federal, state and foreign income tax related matters could be recorded in the future as revised estimates are made or the underlying matters are effectively settled or otherwise resolved. Conversely, the Company could settle positions with the tax authorities for amounts lower than have been accrued. The Company believes it is reasonably possible that, during the next 12 months, the Company’s liability for uncertain tax positions may decrease by approximately $0.7 million.

The Company’s provision for income taxes differs from the federal statutory rate. The differences between the statutory rate and the Company’s provision are as follows:

	2017			2016			2015
Taxes at statutory rate		35.0	%		35.0	%		35.0	%
State taxes, net of federal benefit		4.4	%		3.9	%		3.9	%
Foreign tax rate differential		(0.3	)%		(0.1	)%		(0.3	)%
Tax legislation		(22.6	)%		—			—
Other permanent differences		0.7	%		0.8	%		1.9	%
Prior year tax adjustments		(0.3	)%		(1.0	)%		(1.9	)%
Unrecognized tax benefits		0.1	%		1.0	%		—
Valuation allowance		0.7	%		(0.3	)%		—
Equity-based compensation		(2.1	)%		(1.0	)%		—
Tax credits		(0.6	)%		(0.8	)%		(0.5	)%
Taxes at effective rate		15.0	%		37.5	%		38.1	%

Accumulated Other Comprehensive Loss

12 Months Ended

Dec. 31, 2017

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Accumulated Other Comprehensive Loss

NOTE 11—ACCUMULATED OTHER COMPREHENSIVE LOSS

As of December 31, 2017 and 2016, accumulated other comprehensive loss, net of tax, included the following:

	2017			2016
Foreign currency translation adjustments	$	7,638		$	11,815
Gain on sale of interest rate hedge agreement⁽¹⁾		(2,158	)		(2,175	)
Change in fair value on derivative designated as cash flow hedge⁽²⁾		(441	)		—
Total	$	5,039		$	9,640

(1)

Represents the fair value of an interest rate hedge agreement, designated as a cash flow hedge, which was sold on December 1, 2016. The fair value of the interest rate hedge agreement was recorded in other comprehensive income, net of tax, and will be reclassified to earnings when earnings are impacted by the hedged items, as interest payments are made on the Credit Facility from January 31, 2018 to January 31, 2023. See additional details of the hedge agreement in Note 9—Derivative Instruments and Hedging Activities.

(2)

Represents the change in fair value of an interest rate hedge agreement designated as a cash flow hedge, and entered into on August 31, 2017. The fair value of the interest rate hedge agreement was recorded in other comprehensive income and will be reclassified to earnings when earnings are impacted by the hedged items, as interest payments are made on the Credit Facility from August 31, 2018 to August 31, 2023. See additional details of the hedge agreement in Note 9—Derivative Instruments and Hedging Activities.

Restricted Cash

12 Months Ended

Dec. 31, 2017

Cash And Cash Equivalents [Abstract]

Restricted Cash

NOTE 12—RESTRICTED CASH

The following table provides a reconciliation of cash and cash equivalents, and restricted cash reported within the consolidated balance sheets at December 31, 2017 and 2016 to the total cash, cash equivalents, and restricted cash shown in the consolidated statements of cash flows for the years ended December 31, 2017, 2016, and 2015:

	2017				2016				2015
	Beginning		Ending		Beginning		Ending		Beginning		Ending
Cash and cash equivalents	$	6,042	$	11,809	$	7,747	$	6,042	$	12,122	$	7,747
Restricted cash - current (1)		—		11,191		—		—		—		—
Restricted cash - non-current		1,843		1,266		1,362		1,843		1,478		1,362
Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows	$	7,885	$	24,266	$	9,109	$	7,885	$	13,600	$	9,109

⁽¹⁾	Restricted cash – current for the year ended December 31, 2017 represents amounts held in an escrow account for a future acquisition. See Note 19 – Subsequent Events.

Accounting for Stock-based Compensation

12 Months Ended

Dec. 31, 2017

Accounting For Stock Based Compensation [Abstract]

Accounting for Stock-based Compensation

NOTE 13—ACCOUNTING FOR STOCK-BASED COMPENSATION

Stock Incentive Plans

On June 5, 2015, the Company’s stockholders approved an amendment (the “Amendment”) to the ICF International, Inc. 2010 Omnibus Incentive Plan (as amended, the “Omnibus Plan”). The Amendment, among other items, increased the new shares available for issuance under the Omnibus Plan by 1,540,000 shares from 3,550,000 to 5,090,000 (for an aggregate 5,966,186 shares, which includes shares that remained available under the 2006 Long-Term Equity Incentive Plan when the Omnibus Plan was initially adopted). The Omnibus Plan provides for the granting of options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance units, cash-based awards, and other stock-based awards to all officers, key employees, and non-employee directors of the Company. Under the terms of the Omnibus Plan, shares awarded that are not stock options or stock appreciation rights, are counted as 1.93 shares deducted for every one share delivered under those awards. Shares awarded that are stock options or stock appreciation rights are counted as a single share deducted from the Omnibus Plan for every one share delivered under those awards. As of December 31, 2017, the Company had approximately 1.9 million shares available to grant under the Amended Plan. CSRSUs have no impact on the shares available for grant under the Omnibus Plan, and have no impact on the calculated shares used in earnings per share calculations.

The total stock-based compensation expense for the years ended December 31, 2017, 2016, and 2015, the unrecognized compensation expense at December 31, 2017, and the weighted-average period to recognize the remaining unrecognized shares are as follows:

	Stock-Based Compensation Expense
	Recognized as of December 31,						Unrecognized
	2017		2016		2015		December 31, 2017		Weighted-Average Period to Recognize (years)
Stock Options	$	164	$	909	$	1,546	$	—		—
Restricted Stock Units		7,080		6,325		7,409		12,659		1.9
Cash-Settled Restricted Stock Units		7,253		7,091		4,414		13,922		1.9
Non-Employee Director Awards		671		741		645		—		—
Performance Shares		2,376		877		727		2,717		1.5
Total	$	17,544	$	15,943	$	14,741	$	29,298

The assumptions of employment termination forfeiture rates used in the determination of fair value of stock awards during the 2017 calendar year were based on the Company’s historical average of actual forfeitures from the previous 5 years preceding the reporting period. The expected annualized forfeiture rates used during the 2017 calendar year varied from 1.86% to 19.51%, and the Company does not expect these termination rates to vary significantly in the future.

Stock Options

Option awards are granted with an exercise price equal to the market value of the Company’s common stock on the date of grant. All options outstanding as of December 31, 2017 have a 10-year contractual term. Options generally have a vesting term of three or four years. There were no option awards granted during 2017, 2016, and 2015.

The following table summarizes the changes in outstanding stock options:

	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding at January 1, 2015		766,924		$	28.20
Exercised		(43,919	)	$	21.23
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2015		723,005		$	28.62
Exercised		(128,301	)	$	23.65
Granted	—			$	—
Forfeited/Expired		(7,297	)	$	40.68
Outstanding at December 31, 2016		587,407		$	29.56
Exercised		(175,909	)	$	26.84
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2017		411,498		$	30.71	$	8,965

Vested plus expected to vest at December 31, 2017		411,498		$	30.71	$	8,965
Exercisable at December 31, 2017		411,498		$	30.71	$	8,965

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $52.50 as of December 31, 2017. The total intrinsic value of options exercised was $4.5 million, $2.5 million, and $0.8 million for the years ended December 31, 2017, 2016, and 2015, respectively. The fair value of shares vested was $1.9 million, $1.3 million, and $2.0 million for the years ended December 31, 2017, 2016, and 2015, respectively. As of December 31, 2017, the weighted-average remaining contractual term for options vested was 5.0 years and for exercisable options was 5.0 years.

Information regarding stock options outstanding as of December 31, 2017 is summarized below:

	OPTIONS OUTSTANDING						OPTIONS EXERCISABLE
Range of Exercise Prices	Number Outstanding As of December 31, 2017		Weighted Average Remaining Contractual Term		Weighted Average Exercise Price		Number Exercisable As of December 31, 2017		Weighted Average Exercise Price
$21.77 to $25.00		62,917		3.3	$	21.77		62,917	$	21.77
$25.01 to $28.00		205,332		4.8	$	26.50		205,332	$	26.50
$28.01 to $40.68		143,249		6.1	$	40.68		143,249	$	40.68
$21.77 to $41.00		411,498		5.0	$	30.71		411,498	$	30.71

Restricted Stock Units

RSUs generally have a vesting term of three or four years. On vesting the employee is issued one share of stock for each RSU awarded. The fair value of shares vested was $6.3 million, $7.2 million, and $6.3 million for the years ended December 31, 2017, 2016, and 2015, respectively.

A summary of the Company’s RSUs is presented below.

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested RSUs at January 1, 2015		643,887		$	31.10
Granted		250,159		$	39.04
Vested		(233,899	)	$	26.85
Cancelled		(104,243	)	$	36.76
Non-vested RSUs at December 31, 2015		555,904		$	35.40
Granted		240,868		$	34.68
Vested		(221,659	)	$	32.45
Cancelled		(67,115	)	$	37.60
Non-vested RSUs at December 31, 2016		507,998		$	36.12
Granted		194,227		$	41.41
Vested		(179,974	)	$	35.19
Cancelled		(58,664	)	$	36.04
Non-vested RSUs at December 31, 2017		463,587		$	38.71	$	24,338
RSUs expected to vest in the future		463,587		$	38.71	$	24,338

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $52.50 per share as of December 31, 2017.

Cash-Settled Restricted Stock Units

CSRSUs generally have a vesting term of four years. A summary of the Company’s CSRSUs is presented below.

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested CSRSUs at January 1, 2015		537,119		$	36.36
Granted		121,015		$	39.35
Vested		(78,033	)	$	33.29
Cancelled		(133,438	)	$	38.14
Non-vested CSRSUs at December 31, 2015		446,663		$	37.18
Granted		233,790		$	34.29
Vested		(146,619	)	$	34.70
Cancelled		(70,812	)	$	37.55
Non-vested CSRSUs at December 31, 2016		463,022		$	35.96
Granted		174,419		$	42.06
Vested		(161,576	)	$	40.78
Cancelled		(83,949	)	$	36.43
Non-vested CSRSUs at December 31, 2017		391,916		$	38.80	$	20,576
CSRSUs expected to vest in the future		391,916		$	38.80	$	20,576

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $52.50 per share as of December 31, 2017. The fair value of CSRSUs vested and settled in cash for the years ended December 31, 2017, 2016, and 2015 was $6.9 million, $5.9 million and $2.9 million, respectively.

Non-Employee Director Awards

The Company grants awards of unregistered shares to its non-employee directors on a quarterly basis under its Annual Equity Election. The awards are issued from the Company’s treasury stock and have no impact on the shares available for grant under the Omnibus Plan. Non-employee director awards do not include vesting conditions; thus, there was no unrecognized expense related to these awards at December 31, 2017.

A summary of the Company’s non-employee director awards granted by fiscal year is presented below.

For the Year ended December 31,	Number of shares Granted		Weighted- Average Grant Date Fair Value
2015		18,109	$	35.62
2016		15,299	$	39.32
2017		13,861	$	48.41

Performance Share Awards

In the first quarter of 2015, the Company’s Board of Directors approved a performance-based share program (the “Program”) that provides for the issuance of PSAs to its senior management. Under the Program, the number of PSAs that the participant will receive depends on the Company’s achievement of two performance goals during two performance periods. The performance goals under the Program are based on (i) the Company’s compounded annual growth rate in earnings per share (“EPS”) during a two-year performance period and (ii) the Company’s cumulative total shareholder return (“rTSR”) relative to its peer group during a performance period from the first day of the performance period (typically January 1 of the year awarded) to the last day of the third year of the performance period (typically December 31). The PSAs will only be eligible to vest only following the expiration of the three-year performance period. Actual shares vested will be subject to both continued employment by the Company (barring certain exceptions allowing for partial performance periods) and actual financial measures achieved. The actual number of shares of common stock that will be issued to each participant at the end of the applicable performance period will be determined by multiplying the award by the product of two percentages, one based on the Company’s EPS performance and a second one based on the Company’s rTSR performance, subject to a minimum and maximum performance level. As of December 31, 2017, shares granted during 2015, 2016, and 2017 are within year three, two, and one of the performance period, respectively, and therefore have not vested.

A summary of the Company’s PSAs is presented below.

	Number of Shares			Weighted-Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested PSAs at January 1, 2015		—		$	—
Granted		58,822		$	44.21
Vested		—		$	—
Cancelled		—		$	—
Non-vested PSAs at December 31, 2015		58,822		$	44.21
Granted		74,574		$	37.75
Vested		—		$	—
Cancelled		(3,422	)	$	41.61
Non-vested PSAs at December 31, 2016		129,974		$	40.57
Granted		60,929		$	38.81
Vested		—		$	—
Cancelled		(3,881	)	$	42.83
Non-vested PSAs at December 31, 2017		187,022		$	39.95	$	9,819
PSAs expected to vest in the future		126,846		$	38.09	$	6,659

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $52.50 per share as of December 31, 2017. The fair value of the awards is estimated on the grant date using a Monte Carlo simulation model due to the market condition for the rTSR component. The fair value assumptions using the Monte Carlo simulation model for awards granted in 2017, 2016, and 2015 were 0.0% for dividend yields; 31.3%, 30.9% and 29.3% for historical volatility, respectively; and 1.5%, 1.0%, and 1.0% both risk-free rate of returns, respectively.

Earnings Per Share

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Earnings Per Share

NOTE 14—EARNINGS PER SHARE

EPS is computed by dividing reported net income by the weighted-average number of shares outstanding. Diluted EPS considers the potential dilution that could occur if common stock equivalents of stock options, RSUs, and PSAs were exercised or converted into stock. PSAs are included in the computation of diluted shares only to the extent that the underlying performance conditions (i) are satisfied as of the end of the reporting period or (ii) would be considered satisfied if the end of the reporting period were the end of the related performance period and the result would be dilutive under the treasury stock method. For the years ended December 31, 2017, 2016, and 2015, there were 142, 163,564 and 167,849, respectively, weighted-average shares excluded from the calculation of EPS because they were anti-dilutive.

The dilutive effect of stock options, RSUs, and performance shares for each period reported is summarized below:

(in thousands)	2017		2016		2015
Basic weighted-average shares outstanding		18,766		18,989		19,335
Effect of potential exercise of stock options, RSUs, and performance shares		478		427		328
Diluted weighted-average shares outstanding		19,244		19,416		19,663

Share Repurchase Program	12 Months Ended
Share Repurchase Program	Dec. 31, 2017
Equity [Abstract]
Share Repurchase Program	NOTE 15—SHARE REPURCHASE PROGRAM In the third quarter of 2015, the Company’s board of directors approved the share repurchase plan effective in November 2015 that extended the share repurchase plan through November 2017 and authorized share repurchases in the aggregate up to $75.0 million, not to exceed limits under the Credit Facility. As part of the Company’s modification of the Credit Facility, the prior Credit Facility limits on share repurchases were eliminated to permit unlimited share repurchases, provided the Company’s Leverage Ratio, prior to and after giving effect to such repurchases, is not greater than 3.25 to 1.00. During September 2017, the board of directors approved a new repurchase program and repurchase plan effective November 4, 2017 through November 4, 2019 with a limit of $100.0 million. The limitation under the Credit Facility remains unchanged. Purchases under this program may be made from time to time at prevailing market prices in open market purchases or in privately negotiated transactions pursuant to Rules 10b5-1 and 10b-18 under the Exchange Act and in accordance with applicable insider trading and other securities laws and regulations. The purchases are funded from existing cash balances and/or borrowings, and the repurchased shares are held in treasury and used for general corporate purposes. The timing and extent to which the Company repurchases its shares will depend on market conditions and other corporate considerations at the Company’s sole discretion. During the year ended December 31, 2017, the Company repurchased 684,335 shares at a total cost of $30.7 million under this program. As of December 31, 2017, approximately $100.0 million remained available under the share repurchase plan.

Fair Value

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value

NOTE 16—FAIR VALUE

The Company measures and reports certain financial assets and liabilities at fair value in accordance with ASC 820, Fair Value Measurements and Disclosures (“ASC 820”). Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. Generally, fair value is based on observable quoted market prices or derived from observable market data when such market prices or data are available. ASC 820 establishes a three-level hierarchy used to estimate fair value by which each level is categorized based on the priority of the inputs used to measure fair value:

•

Level 1: Quoted prices that are available in active markets for identical assets or liabilities;

•

Level 2: Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active; inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates and yield curves that are observable at commonly quoted intervals, and implied volatilities); and inputs derived principally from or corroborated by observable market data by correlation or other means; and

•

Level 3: Uses inputs that are unobservable and require the Company to make certain assumptions and require significant estimation and judgment from management to use in pricing the fair value of the assets and liabilities.

As of December 31, 2017 and 2016, there were no assets or liabilities measured at Level 3 on a recurring basis.

Certain financial instruments, including cash and cash equivalents, contract receivables, and accounts payable are carried at cost, which, due to their short maturities, approximates their fair values at December 31, 2017 and 2016. The carrying value of other long-term liabilities related to capital expenditure obligations approximates their fair value at December 31, 2017 and 2016 based on the current rates offered to the Company for similar instruments with comparable maturities (Level 2). The Company believes the carrying value of its Credit Facility at December 31, 2017 and 2016 approximates the estimated fair value for debt with similar terms, interest rates, and remaining maturities currently available to companies with similar credit ratings (Level 2). The Company applies the provisions of ASC 820 to its assets and liabilities that are required to be measured at fair value pursuant to other accounting standards, including assets and liabilities resulting from the Company’s nonqualified deferred compensation plan, interest rate swap agreement (see Note 9—Derivative Instruments and Hedging Activities), and foreign currency forward contract agreements not eligible for hedge accounting. The impact of the amounts recorded for the nonqualified deferred compensation plan, interest rate swap agreement, and the forward contract agreements was immaterial to the consolidated financial statements.

Commitments And Contingencies Disclosure [Abstract]

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies

NOTE 17—COMMITMENTS AND CONTINGENCIES

Litigation and Claims

The Company is involved in various legal matters and proceedings arising in the ordinary course of business. While these matters and proceedings cause it to incur costs, including, but not limited to, attorneys’ fees, the Company currently believes that any ultimate liability arising out of these matters and proceedings will not have a material adverse effect on the Company’s financial position, results of operations, or cash flows.

Road Home Contract

On June 10, 2016, the Office of Community Development (the “OCD”) of the State of Louisiana filed a written administrative demand with the Louisiana Commissioner of Administration against ICF Emergency Management Services, L.L.C. (“ICF Emergency”), a subsidiary of the Company, in connection with ICF Emergency’s administration of the Road Home Program (the “Program”). The Program contract was a three-year, $912 million contract awarded to the Company in 2006 and that ended, as scheduled, in 2009.

The Program was primarily intended to help homeowners and landlords of small rental properties affected by Hurricanes Rita and Katrina. In its administrative demand, the OCD sought approximately $200.8 million in alleged overpayments to Program grant recipients. The State separately supplemented the amount of recovery it is seeking in total approximately $220.2 million. The State of Louisiana, through the Division of Administration, also filed suit in Louisiana state court on June 10, 2016 broadly alleging and seeking recoupment for the same claim made in the administrative proceeding submission before the Louisiana Commissioner of Administration. On September 21, 2016, the Commissioner of the Division of Administration notified OCD and the Company of his decision to defer jurisdiction of the administrative demand filed by the OCD. In so doing, the Commissioner declined to reach a decision on the merits, stated that his deferral would not be deemed to grant or deny any portion of the OCD’s claim, and authorized the parties to proceed on the matter in the previously filed judicial proceeding. The Company continues to believe that this claim has no merit, intends to vigorously defend its position, and has therefore not recorded a liability as of December 31, 2017.

Operating Leases

On March 8, 2010, the Company entered into a new lease that replaced its prior headquarters lease, which was due to expire in October 2012. The new lease was initially for approximately 258,000 square feet, with approximately 72,000 square feet of additional space subsequently added. The lease commenced on April 1, 2010, and will expire on December 31, 2022. Base rent under the agreement is approximately $0.9 million per month with annual escalations fixed at 2.5% per year, yielding a total lease commitment of approximately $150.6 million over the twelve-year term of the lease.

The Company has entered into various other operating leases for equipment and office space. Certain facility leases may contain fixed escalation clauses, certain facility leases require the Company to pay operating expenses in addition to base rental amounts, and nine leases require the Company to maintain letters of credit. Future minimum rental payments under all non-cancelable operating leases are as follows:

Year ending December 31,	(in thousands)
2018	$	36,238
2019		34,223
2020		31,459
2021		31,091
2022		29,761
Thereafter		30,998
	$	193,770

Minimum lease payments have been reduced by minimum sublease rentals of $1.4 million due in the future under non-cancelable subleases.

Rent expense is recognized on a straight-line basis over the lease term, net of sublease payments. Rent expense consists of the following for the years ended December 31:

(in thousands)	2017			2016			2015
Rent	$	36,269		$	39,537		$	40,009
Sublease income		(142	)		(147	)		(32	)
Total rent expense	$	36,127		$	39,390		$	39,977

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Employee Benefit Plans	NOTE 18—EMPLOYEE BENEFIT PLANS Retirement Savings Plan Effective June 30, 1999, the Company established the ICF Consulting Group Retirement Savings Plan (the “Retirement Savings Plan”). The Retirement Savings Plan is a defined contribution profit sharing plan with a cash or deferred arrangement under Section 401(k) of the Internal Revenue Code. Participants in the Retirement Savings Plan are able to elect to defer up to 70% of their compensation subject to statutory limitations, and are entitled to receive 100% employer matching contributions for the first 3% and 50% for the next 2% of their compensation. Contribution expense related to the Retirement Savings Plan for the years ended December 31, 2017, 2016, and 2015, was approximately $15.1 million, $14.9 million, and $13.1 million, respectively. Deferred Compensation Plan Certain key employees of the Company are eligible to defer a specified percentage of their cash compensation by having it contributed to a nonqualified deferred compensation plan. Eligible employees may elect to defer up to 80% of their base salary and up to 100% of performance bonuses, reduced by any amounts withheld for the payment of taxes or other deductions required by law. Participants are at all times 100% vested in their account balances. The Company funds its deferred compensation liabilities by making cash contributions to a Rabbi Trust at the time the salary or bonus being deferred would otherwise be payable to the employee. The liability to plan participants is materially funded at all times and the plan does not have a material net impact on the Company’s results of operations. Employee Stock Purchase Plan The Company has a 2006 Employee Stock Purchase Plan (“ESPP”) under which one million shares have been authorized for issuance. The ESPP allows eligible employees to purchase shares of our common stock through payroll deductions up to $25,000 per calendar year over six-month offering periods at a discount not to exceed 5% of the market value on the date of each purchase period. For the year ended December 31, 2017, 27,285 shares were purchased by employees, at an average purchase price of $47.34, and 724,826 shares remain available for future issuance. The Company does not recognize compensation expense related to the ESPP.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	NOTE 19—SUBSEQUENT EVENTS In January 2018, the Company acquired The Future Customer, a leading boutique loyalty strategy and marketing company based in London. The acquisition was immaterial to the financial statements taken as a whole. On February 27, 2018, the Company’s board of directors approved a $0.14 per share cash dividend. The dividend will be paid on April 16, 2018 to shareholders of record as of the close of business on March 30, 2018.

Supplemental Information

12 Months Ended

Dec. 31, 2017

Disclosure Text Block Supplement [Abstract]

Supplemental Information

NOTE 20—SUPPLEMENTAL INFORMATION

Valuation and Qualifying Accounts

Allowance for Doubtful Accounts

	2017			2016			2015
Balance at beginning of period	$	2,591		$	2,138			1,887
Bad debt expense		1,480			1,089			268
Write-offs, net of recoveries		(219	)		(635	)		(8	)
Effect of foreign currency translation		1			(1	)		(9	)
Balance at end of period	$	3,853		$	2,591		$	2,138

Income Tax Valuation Allowance

	2017		2016		2015
Balance at beginning of period	$	1,131	$	933		542
Provision for income taxes - valuation allowance		505		198		391
Balance at end of period	$	1,636	$	1,131	$	933

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information

NOTE 21—SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)

	2017								2016
	1Q		2Q		3Q		4Q		1Q ⁽¹⁾		2Q		3Q		4Q
Contract revenue	$	296,295	$	306,392	$	305,301	$	321,174	$	283,599	$	305,419	$	306,520	$	289,559
Operating income	$	16,633	$	22,208	$	23,396	$	20,181	$	17,694	$	19,358	$	23,776	$	21,965
Net income	$	10,177	$	11,937	$	13,692	$	27,070	$	9,891	$	10,583	$	13,437	$	12,673
Earnings per share:
Basic	$	0.54	$	0.64	$	0.73	$	1.45	$	0.52	$	0.56	$	0.71	$	0.67
Diluted	$	0.52	$	0.63	$	0.72	$	1.41	$	0.51	$	0.55	$	0.70	$	0.65
Weighted-average common shares outstanding (in thousands)
Basic		18,972		18,775		18,666		18,646		18,994		19,008		18,965		18,988
Diluted		19,423		19,086		19,024		19,136		19,273		19,293		19,329		19,512

⁽¹⁾	Includes adjustments for the adoption ASU 2016-09 in the second quarter of 2016.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Cash and Cash Equivalents

Use of Estimates

Revenue Recognition

•

Specific Performance: When the services to be performed consist of a single act, revenue is recognized at the time the act is performed or at the completion of the single service.

•

The Company considers cash on deposit and all highly liquid investments with original maturities of three months or less when purchased to be cash and cash equivalents.

Restricted Cash

The Company has restricted cash representing amounts held in escrow accounts and/or not readily available due to contractual restrictions.

Allowance for Doubtful Accounts

Property and Equipment

Goodwill and Other Intangible Assets

Impairment

Capitalized Software

Deferred Rent

Stock-based Compensation

Other Comprehensive Income (Loss)

	Year ended December 31,
	2017			2016			2015
Foreign currency translation adjustments	$	4,177		$	(4,321	)	$	(5,676	)
Foreign currency realized losses reclassified into earnings		—			(3	)		666
Change in fair value of derivative designated as cash flow hedge		441			—			—
Gain on sale of interest rate hedging agreement, net of tax⁽¹⁾		(17	)		2,175			—
Other comprehensive income (loss), net of tax⁽²⁾	$	4,601		$	(2,149	)	$	(5,010	)

⁽¹⁾

⁽²⁾	Net of tax of $1.0 million, $2.2 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Derivative Instruments

Income Taxes

Treasury Shares

Treasury shares are accounted for under the cost method.

Segment Customer and Geographic Information

Segment, Customer and Geographic Information

At December 31, 2017 and 2016, long-lived assets held internationally were not material.

Risk and Uncertainties

Risks and Uncertainties

Recent Accounting Pronouncements

Recent Accounting Pronouncements Adopted

Cash Receipts and Cash Payments

Restricted Cash

	Year Ended December 31, 2016						Year Ended December 31, 2015
	As Reported			As Adjusted			As Reported			As Adjusted
Restricted cash	$	(494	)	$	—		$	116		$	—
Net Cash Provided by Operating Activities		79,563			80,057			76,319			76,203
Effect of exchange rate changes on cash		(403	)		(416	)		(1,746	)		(1,746	)
(Decrease) Increase in Cash and Cash Equivalents		(1,705	)		—			(4,375	)		—
Increase in Cash, Cash Equivalents, and Restricted Cash		—			(1,224	)		—			(4,491	)
Cash and Cash Equivalents, Beginning Period		7,747			—			12,122			—
Cash, Cash Equivalents, and Restricted Cash, Beginning Period		—			9,109			—			13,600
Cash and Cash Equivalents, End of Period		6,042			—			7,747			—
Cash, Cash Equivalents, and Restricted Cash, End of Period		—			7,885			—			9,109

Goodwill

Derivative and Hedging

Recent Accounting Pronouncements Not Yet Adopted

Revenue Recognition

Leases

Accumulated other comprehensive loss

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Other Comprehensive Income (Loss) Net of Tax Activity

. The activity included in other comprehensive income (loss), net of tax, in the Company’s consolidated statements of comprehensive income for each period reported is summarized below.

	Year ended December 31,
	2017			2016			2015
Foreign currency translation adjustments	$	4,177		$	(4,321	)	$	(5,676	)
Foreign currency realized losses reclassified into earnings		—			(3	)		666
Change in fair value of derivative designated as cash flow hedge		441			—			—
Gain on sale of interest rate hedging agreement, net of tax⁽¹⁾		(17	)		2,175			—
Other comprehensive income (loss), net of tax⁽²⁾	$	4,601		$	(2,149	)	$	(5,010	)

⁽¹⁾

⁽²⁾	Net of tax of $1.0 million, $2.2 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Summary of Previously Reported Consolidated Statement of Cash Flows

The impact of the adoption on the Company’s previously reported consolidated statements of cash flows is summarized as follows:

	Year Ended December 31, 2016						Year Ended December 31, 2015
	As Reported			As Adjusted			As Reported			As Adjusted
Restricted cash	$	(494	)	$	—		$	116		$	—
Net Cash Provided by Operating Activities		79,563			80,057			76,319			76,203
Effect of exchange rate changes on cash		(403	)		(416	)		(1,746	)		(1,746	)
(Decrease) Increase in Cash and Cash Equivalents		(1,705	)		—			(4,375	)		—
Increase in Cash, Cash Equivalents, and Restricted Cash		—			(1,224	)		—			(4,491	)
Cash and Cash Equivalents, Beginning Period		7,747			—			12,122			—
Cash, Cash Equivalents, and Restricted Cash, Beginning Period		—			9,109			—			13,600
Cash and Cash Equivalents, End of Period		6,042			—			7,747			—
Cash, Cash Equivalents, and Restricted Cash, End of Period		—			7,885			—			9,109

Contract Receivables (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Summary of Contract Receivables

Contract receivables consisted of the following at December 31:

	2017			2016
Billed	$	169,027		$	168,012
Unbilled		117,037			108,432
Retainages		6,160			5,088
Other		3,144			2,424
Allowance for doubtful accounts		(3,853	)		(2,591	)
Contract receivables, net	$	291,515		$	281,365

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Property and Equipment

Property and equipment consisted of the following at December 31:

	2017			2016
Leasehold improvements	$	18,873		$	17,847
Software		42,835			41,269
Furniture and equipment		26,076			26,570
Computers		28,826			28,874
		116,610			114,560
Accumulated depreciation and amortization		(78,558	)		(74,076	)
Total property and equipment, net	$	38,052		$	40,484

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Changes in Carrying Amount of Goodwill

The changes in the carrying amount of goodwill for the fiscal years ended December 31 were as follows:

	2017		2016
Balance as of January 1	$	683,683	$	687,404
Goodwill resulting from the Trade NTE business combination		—		191
Goodwill resulting from the Mostra business combination		—		654
Goodwill resulting from the Olson business combination		—		267
Effect of foreign currency translation		2,425		(4,833	)
Total goodwill	$	686,108	$	683,683

Schedule of Other Intangibles

Other intangibles consisted of the following at December 31:

	2017
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value
Customer-related	$	84,878	$	(49,782	)	$	35,096
Developed technology		1,463		(1,350	)		113
Total amortizable intangible assets		86,341		(51,132	)		35,209
Intangible with indefinite life		95		—			95
Total other intangible assets	$	86,436	$	(51,132	)	$	35,304

	2016
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value
Customer-related	$	115,806	$	(70,090	)	$	45,716
Developed technology		1,463		(1,145	)		318
Total amortizable intangible assets		117,269		(71,235	)		46,034
Intangible with indefinite life		95		—			95
Total other intangible assets	$	117,364	$	(71,235	)	$	46,129

Schedule of Estimated Future Amortization Expense Relating to Intangible Assets

The estimated future amortization expense relating to intangible assets is as follows:


Year ending December 31,
2018	$	8,441
2019		6,132
2020		4,532
2021		4,082
2022		4,125
Thereafter		7,897
Total	$	35,209

Accrued Salaries and Benefits (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Accrued Salaries and Benefits

Accrued salaries and benefits consisted of the following at December 31:

	2017		2016
Accrued paid time off and leave	$	11,904	$	11,342
Accrued salaries		9,343		9,443
Accrued bonuses, liability-classified awards and commissions		16,909		13,025
Accrued payroll taxes and withholdings		2,557		1,948
Accrued medical		3,720		3,026
Other		1,212		979
Total accrued salaries and benefits	$	45,645	$	39,763

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following at December 31:

	2017		2016
Accrued subcontractor and other direct costs	$	47,508	$	30,153
Deposits		6,641		12,389
Accrued IT and software licensing costs		2,261		5,349
Accrued taxes and insurance premiums		1,963		1,306
Accrued lease exit and facilities costs		1,591		77
Accrued interest		705		841
Accrued professional services		1,131		795
Other accrued expenses and current liabilities		3,280		1,721
Total accrued expenses and other current liabilities	$	65,080	$	52,631

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

Long-term debt outstanding and the weighted average interest rate at December 31 is summarized as follows:

2017

2016

Debt Outstanding

Weighted Average

Interest Rate

Debt Outstanding

Weighted Average

Interest Rate

Revolving Line of Credit/Swing Line

206,250

2.65

259,389

2.46

Income Before Income Taxes

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21521-112644

+ Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

The domestic and foreign components of income before provision for income taxes are as follows for the years ended December 31:

	2017		2016		2015
Domestic	$	69,347	$	69,159	$	54,150
Foreign		4,639		5,348		9,450
Income before income taxes	$	73,986	$	74,507	$	63,600

Income Tax Expense Components

Income tax expense consisted of the following for the years ended December 31:

	2017			2016			2015
Current:
Federal	$	12,995		$	12,979		$	14,797
State		3,243			3,514			2,669
Foreign		1,476			1,932			1,475
Total current		17,714			18,425			18,941
Deferred:
Federal		(9,425	)		8,872			4,562
State		2,749			1,222			512
Foreign		72			(596	)		216
Total deferred		(6,604	)		9,498			5,290
Income tax expense	$	11,110		$	27,923		$	24,231

Deferred Tax Assets (Liabilities)

Deferred tax assets (liabilities) consisted of the following at December 31:

	2017			2016
Deferred Tax Assets
Allowance for bad debt	$	1,003		$	1,008
Accrued paid time off		1,624			2,592
Accrued bonus		—			55
Foreign net operating loss (NOL) carry forward		1,301			1,371
Federal/state net operating loss (NOL) carry forward		507			3,010
Stock option compensation		2,726			4,292
Deferred rent		3,355			5,423
Deferred compensation		3,238			3,662
Foreign tax credits		505			2,631
State tax credits		1,785			1,784
Federal tax credits		—			225
Foreign exchange		2,051			5,349
Accrued liabilities and other		3,272			3,378
		21,367			34,780
Less: Valuation Allowance		(1,636	)		(1,131	)
Total Deferred Tax Assets		19,731			33,649

Deferred Tax Liabilities
Retention		(1,375	)		(1,684	)
Prepaid expenses		(1,045	)		(1,654	)
Payroll taxes		(489	)		(617	)
Unbilled revenue		(5,407	)		(8,728	)
Depreciation		(4,773	)		(6,664	)
Amortization		(39,993	)		(51,842	)
Deferred gain and other		—			(1,574	)
Total Deferred Tax Liabilities		(53,082	)		(72,763	)
Total Net Deferred Tax Liability	$	(33,351	)	$	(39,114	)

Unrecognized Tax Benefit Reconciliation

The unrecognized tax benefit reconciliation, excluding penalty and interest, is as follows:

Unrecognized tax benefits at January 1, 2015	$	702
Decrease attributable to settlements		(174	)
Increase attributable to tax positions taken during a prior period		12
Decrease attributable to lapse of statute of limitations		(140	)
Unrecognized tax benefits at December 31, 2015	400
Increase attributable to tax positions taken during a prior period		925
Decrease attributable to lapse of statute of limitations		(140	)
Unrecognized tax benefits at December 31, 2016		1,185
Decrease attributable to lapse of statute of limitations		(365	)
Unrecognized tax benefits at December 31, 2017	$	820

Effective Income Tax Rate Reconciliation

The Company’s provision for income taxes differs from the federal statutory rate. The differences between the statutory rate and the Company’s provision are as follows:

	2017			2016			2015
Taxes at statutory rate		35.0	%		35.0	%		35.0	%
State taxes, net of federal benefit		4.4	%		3.9	%		3.9	%
Foreign tax rate differential		(0.3	)%		(0.1	)%		(0.3	)%
Tax legislation		(22.6	)%		—			—
Other permanent differences		0.7	%		0.8	%		1.9	%
Prior year tax adjustments		(0.3	)%		(1.0	)%		(1.9	)%
Unrecognized tax benefits		0.1	%		1.0	%		—
Valuation allowance		0.7	%		(0.3	)%		—
Equity-based compensation		(2.1	)%		(1.0	)%		—
Tax credits		(0.6	)%		(0.8	)%		(0.5	)%
Taxes at effective rate		15.0	%		37.5	%		38.1	%

Accumulated Other Comprehensive Loss (Tables)

12 Months Ended

Dec. 31, 2017

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Schedule of Accumulated Other Comprehensive Loss, Net of Tax

As of December 31, 2017 and 2016, accumulated other comprehensive loss, net of tax, included the following:

	2017			2016
Foreign currency translation adjustments	$	7,638		$	11,815
Gain on sale of interest rate hedge agreement⁽¹⁾		(2,158	)		(2,175	)
Change in fair value on derivative designated as cash flow hedge⁽²⁾		(441	)		—
Total	$	5,039		$	9,640

(1)

(2)

Restricted Cash (Tables)

12 Months Ended

Dec. 31, 2017

Restricted Cash And Cash Equivalents Current [Abstract]

Reconciliation of Cash and Cash Equivalents, and Restricted Cash

	2017				2016				2015
	Beginning		Ending		Beginning		Ending		Beginning		Ending
Cash and cash equivalents	$	6,042	$	11,809	$	7,747	$	6,042	$	12,122	$	7,747
Restricted cash - current (1)		—		11,191		—		—		—		—
Restricted cash - non-current		1,843		1,266		1,362		1,843		1,478		1,362
Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows	$	7,885	$	24,266	$	9,109	$	7,885	$	13,600	$	9,109

⁽¹⁾	Restricted cash – current for the year ended December 31, 2017 represents amounts held in an escrow account for a future acquisition. See Note 19 – Subsequent Events.

Accounting for Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Schedule of Stock-based Compensation Expense

	Stock-Based Compensation Expense
	Recognized as of December 31,						Unrecognized
	2017		2016		2015		December 31, 2017		Weighted-Average Period to Recognize (years)
Stock Options	$	164	$	909	$	1,546	$	—		—
Restricted Stock Units		7,080		6,325		7,409		12,659		1.9
Cash-Settled Restricted Stock Units		7,253		7,091		4,414		13,922		1.9
Non-Employee Director Awards		671		741		645		—		—
Performance Shares		2,376		877		727		2,717		1.5
Total	$	17,544	$	15,943	$	14,741	$	29,298

Outstanding Stock Option Activity

The following table summarizes the changes in outstanding stock options:

	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding at January 1, 2015		766,924		$	28.20
Exercised		(43,919	)	$	21.23
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2015		723,005		$	28.62
Exercised		(128,301	)	$	23.65
Granted	—			$	—
Forfeited/Expired		(7,297	)	$	40.68
Outstanding at December 31, 2016		587,407		$	29.56
Exercised		(175,909	)	$	26.84
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2017		411,498		$	30.71	$	8,965

Vested plus expected to vest at December 31, 2017		411,498		$	30.71	$	8,965
Exercisable at December 31, 2017		411,498		$	30.71	$	8,965

Schedule of Stock Options Outstanding by Exercise Price Range

Information regarding stock options outstanding as of December 31, 2017 is summarized below:

	OPTIONS OUTSTANDING						OPTIONS EXERCISABLE
Range of Exercise Prices	Number Outstanding As of December 31, 2017		Weighted Average Remaining Contractual Term		Weighted Average Exercise Price		Number Exercisable As of December 31, 2017		Weighted Average Exercise Price
$21.77 to $25.00		62,917		3.3	$	21.77		62,917	$	21.77
$25.01 to $28.00		205,332		4.8	$	26.50		205,332	$	26.50
$28.01 to $40.68		143,249		6.1	$	40.68		143,249	$	40.68
$21.77 to $41.00		411,498		5.0	$	30.71		411,498	$	30.71

Summary of Non-employee Director Awards Granted

A summary of the Company’s non-employee director awards granted by fiscal year is presented below.

For the Year ended December 31,	Number of shares Granted		Weighted- Average Grant Date Fair Value
2015		18,109	$	35.62
2016		15,299	$	39.32
2017		13,861	$	48.41

Summary of Performance Shares Activity

A summary of the Company’s PSAs is presented below.

	Number of Shares			Weighted-Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested PSAs at January 1, 2015		—		$	—
Granted		58,822		$	44.21
Vested		—		$	—
Cancelled		—		$	—
Non-vested PSAs at December 31, 2015		58,822		$	44.21
Granted		74,574		$	37.75
Vested		—		$	—
Cancelled		(3,422	)	$	41.61
Non-vested PSAs at December 31, 2016		129,974		$	40.57
Granted		60,929		$	38.81
Vested		—		$	—
Cancelled		(3,881	)	$	42.83
Non-vested PSAs at December 31, 2017		187,022		$	39.95	$	9,819
PSAs expected to vest in the future		126,846		$	38.09	$	6,659

Restricted Stock Units (RSUs)

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Schedule of Restricted Stock Unit Activity

A summary of the Company’s RSUs is presented below.

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested RSUs at January 1, 2015		643,887		$	31.10
Granted		250,159		$	39.04
Vested		(233,899	)	$	26.85
Cancelled		(104,243	)	$	36.76
Non-vested RSUs at December 31, 2015		555,904		$	35.40
Granted		240,868		$	34.68
Vested		(221,659	)	$	32.45
Cancelled		(67,115	)	$	37.60
Non-vested RSUs at December 31, 2016		507,998		$	36.12
Granted		194,227		$	41.41
Vested		(179,974	)	$	35.19
Cancelled		(58,664	)	$	36.04
Non-vested RSUs at December 31, 2017		463,587		$	38.71	$	24,338
RSUs expected to vest in the future		463,587		$	38.71	$	24,338

Cash Settled RSUs [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Schedule of Restricted Stock Unit Activity

CSRSUs generally have a vesting term of four years. A summary of the Company’s CSRSUs is presented below.

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested CSRSUs at January 1, 2015		537,119		$	36.36
Granted		121,015		$	39.35
Vested		(78,033	)	$	33.29
Cancelled		(133,438	)	$	38.14
Non-vested CSRSUs at December 31, 2015		446,663		$	37.18
Granted		233,790		$	34.29
Vested		(146,619	)	$	34.70
Cancelled		(70,812	)	$	37.55
Non-vested CSRSUs at December 31, 2016		463,022		$	35.96
Granted		174,419		$	42.06
Vested		(161,576	)	$	40.78
Cancelled		(83,949	)	$	36.43
Non-vested CSRSUs at December 31, 2017		391,916		$	38.80	$	20,576
CSRSUs expected to vest in the future		391,916		$	38.80	$	20,576

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Schedule of Dilutive Effect of Stock Options RSUs and PSAs

The dilutive effect of stock options, RSUs, and performance shares for each period reported is summarized below:

(in thousands)	2017		2016		2015
Basic weighted-average shares outstanding		18,766		18,989		19,335
Effect of potential exercise of stock options, RSUs, and performance shares		478		427		328
Diluted weighted-average shares outstanding		19,244		19,416		19,663

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases

Year ending December 31,	(in thousands)
2018	$	36,238
2019		34,223
2020		31,459
2021		31,091
2022		29,761
Thereafter		30,998
	$	193,770

Operating Leases of Lessee Disclosure

(in thousands)	2017			2016			2015
Rent	$	36,269		$	39,537		$	40,009
Sublease income		(142	)		(147	)		(32	)
Total rent expense	$	36,127		$	39,390		$	39,977

Supplemental Information (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure Text Block Supplement [Abstract]

Schedule of Allowance for Doubtful Accounts

Allowance for Doubtful Accounts

	2017			2016			2015
Balance at beginning of period	$	2,591		$	2,138			1,887
Bad debt expense		1,480			1,089			268
Write-offs, net of recoveries		(219	)		(635	)		(8	)
Effect of foreign currency translation		1			(1	)		(9	)
Balance at end of period	$	3,853		$	2,591		$	2,138

Schedule of Income Tax Valuation Allowance

Income Tax Valuation Allowance

	2017		2016		2015
Balance at beginning of period	$	1,131	$	933		542
Provision for income taxes - valuation allowance		505		198		391
Balance at end of period	$	1,636	$	1,131	$	933

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information

	2017								2016
	1Q		2Q		3Q		4Q		1Q ⁽¹⁾		2Q		3Q		4Q
Contract revenue	$	296,295	$	306,392	$	305,301	$	321,174	$	283,599	$	305,419	$	306,520	$	289,559
Operating income	$	16,633	$	22,208	$	23,396	$	20,181	$	17,694	$	19,358	$	23,776	$	21,965
Net income	$	10,177	$	11,937	$	13,692	$	27,070	$	9,891	$	10,583	$	13,437	$	12,673
Earnings per share:
Basic	$	0.54	$	0.64	$	0.73	$	1.45	$	0.52	$	0.56	$	0.71	$	0.67
Diluted	$	0.52	$	0.63	$	0.72	$	1.41	$	0.51	$	0.55	$	0.70	$	0.65
Weighted-average common shares outstanding (in thousands)
Basic		18,972		18,775		18,666		18,646		18,994		19,008		18,965		18,988
Diluted		19,423		19,086		19,024		19,136		19,273		19,293		19,329		19,512

Basis of Presentation and Nature of Operations - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2017 Office
Reclassification of Deferred Compensation Liabilities from Accrued Salaries and Benefits to Long-term Noncurrent Classification
Basis of Presentation and Nature of Operations [Line Items]
Prior period reclassification adjustment \| $	$ 4.3
Domestic
Basis of Presentation and Nature of Operations [Line Items]
Number of offices		59
International
Basis of Presentation and Nature of Operations [Line Items]
Number of offices		23

Summary of Significant Accounting Policies - Additional Information (Details)

3 Months Ended

12 Months Ended

Dec. 31, 2017

USD ($)

Sep. 30, 2017

USD ($)

Jun. 30, 2017

USD ($)

Mar. 31, 2017

USD ($)

Dec. 31, 2016

USD ($)

Sep. 30, 2016

USD ($)

Jun. 30, 2016

USD ($)

Mar. 31, 2016

USD ($)

^[1]

Dec. 31, 2017

USD ($)

Segment

Dec. 31, 2016

USD ($)

Dec. 31, 2015

USD ($)

Summary Of Significant Accounting Policies [Line Items]

Number of reportable segments | Segment

Goodwill, impaired, accumulated impairment loss

$ 0

Goodwill, impairment loss

$ 0

Performance based share awards, performance period

3 years

Number of operating segments | Segment

Foreign financial institutions, actual deposits

321,174,000

$ 305,301,000

$ 306,392,000

$ 296,295,000

$ 289,559,000

$ 306,520,000

$ 305,419,000

$ 283,599,000

$ 1,229,162,000

$ 1,185,097,000

$ 1,132,232,000

$ 10,400,000

$ 5,400,000

10,400,000

5,400,000

Federal Government Agencies And Departments

Summary Of Significant Accounting Policies [Line Items]

Federal Government Agencies And Departments | Customer Concentration Risk | Sales Revenue, Net

$ 550,300,000

$ 563,000,000

$ 540,000,000

Summary Of Significant Accounting Policies [Line Items]

Concentration risk, percentage

45.00%

48.00%

International Clients | Geographic Concentration Risk | Sales Revenue, Net

Summary Of Significant Accounting Policies [Line Items]

Concentration risk, percentage

9.00%

10.00%

11.00%

Minimum

Summary Of Significant Accounting Policies [Line Items]

Property and equipment, estimated useful life

2 years

Summary Of Significant Accounting Policies [Line Items]

4 years

Minimum | Other Assets

Summary Of Significant Accounting Policies [Line Items]

3 years

Maximum

Property and equipment, estimated useful life

7 years

Summary Of Significant Accounting Policies [Line Items]

10 years

Maximum | Other Assets

5 years

[1]	Includes adjustments for the adoption ASU 2016-09 in the second quarter of 2016.

Summary of Significant Accounting Policies - Other Comprehensive Income (Loss) Net of Tax Activity (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Foreign currency translation adjustments

$ 4,177

$ (4,321)

$ (5,676)

Foreign currency realized losses reclassified into earnings

(3)

666

Change in fair value of derivative designated as cash flow hedge

441

Gain on sale of interest rate hedging agreement, net of tax(1)

^[1]

(17)

2,175

Other comprehensive income (loss), net of tax

^[2]

$ 4,601

$ (2,149)

$ (5,010)

[1]

[2]

Net of tax of $1.0 million, $2.2 million, and $1.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Summary of Significant Accounting Policies - Other Comprehensive Income (Loss) Net of Tax Activity (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Other comprehensive income (loss), tax	$ 1.0	$ 2.2	$ 1.0

Summary of Significant Accounting Policies - Previously Reported Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Net Cash Provided by Operating Activities	$ 117,191	$ 80,057	$ 76,203
Effect of exchange rate changes on cash	1,094	(416)	(1,746)
Increase in Cash, Cash Equivalents, and Restricted Cash	16,381	(1,224)	(4,491)
Cash and Cash Equivalents, Beginning Period	6,042	7,747	12,122
Cash, Cash Equivalents, and Restricted Cash, Beginning of Period	7,885	9,109	13,600
Cash and Cash Equivalents, End of Period	11,809	6,042	7,747
Cash, Cash Equivalents, and Restricted Cash, End of Period	24,266	7,885	9,109
New Accounting Pronouncement Early Adoption Effect \| ASU 2016-18
Summary Of Significant Accounting Policies [Line Items]
Net Cash Provided by Operating Activities		80,057	76,203
Effect of exchange rate changes on cash		(416)	(1,746)
Increase in Cash, Cash Equivalents, and Restricted Cash		(1,224)	(4,491)
Cash, Cash Equivalents, and Restricted Cash, Beginning of Period	7,885	9,109	13,600
Cash, Cash Equivalents, and Restricted Cash, End of Period		7,885	9,109
New Accounting Pronouncement Early Adoption Effect \| ASU 2016-18 \| As Reported
Summary Of Significant Accounting Policies [Line Items]
Restricted cash		(494)	116
Net Cash Provided by Operating Activities		79,563	76,319
Effect of exchange rate changes on cash		(403)	(1,746)
(Decrease) Increase in Cash and Cash Equivalents		(1,705)	(4,375)
Cash and Cash Equivalents, Beginning Period	$ 6,042	7,747	12,122
Cash and Cash Equivalents, End of Period		$ 6,042	$ 7,747

Contract Receivables - Additional Information (Details)	12 Months Ended
Contract Receivables - Additional Information (Details)	Dec. 31, 2017
Receivables [Abstract]
Majority of unbilled receivables will be substantially billed and collected	1 year

Contract Receivables - Summary of Contract Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Billed	$ 169,027	$ 168,012
Unbilled	117,037	108,432
Retainages	6,160	5,088
Other	3,144	2,424
Allowance for doubtful accounts	(3,853)	(2,591)
Contract receivables, net	$ 291,515	$ 281,365

Property and Equipment - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 116,610	$ 114,560
Accumulated depreciation and amortization	(78,558)	(74,076)
Total property and equipment, net	38,052	40,484
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	18,873	17,847
Software and Software Development Costs
Property Plant And Equipment [Line Items]
Property and equipment, gross	42,835	41,269
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	26,076	26,570
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 28,826	$ 28,874

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 17,691	$ 16,638	$ 16,222

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Balance as of January 1	$ 683,683,000	$ 687,404,000
Effect of foreign currency translation	2,425,000	(4,833,000)
Balance as of December 31	$ 686,108,000	683,683,000
Trade NTE
Goodwill resulting from business combinations		191,000
Mostra
Goodwill resulting from business combinations		654,000
Olson
Goodwill resulting from business combinations		$ 267,000

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amortization of intangible assets	$ 10,888	$ 12,481	$ 17,184
Minimum
Finite-lived intangible asset, useful life	4 years
Maximum
Finite-lived intangible asset, useful life	10 years
Weighted Average
Finite-lived intangible asset, useful life	9 years 1 month 6 days
Weighted Average \| Customer Relationships
Finite-lived intangible asset, useful life	9 years 1 month 6 days
Weighted Average \| Technology-Based Intangible Assets
Finite-lived intangible asset, useful life	5 years 6 months

Goodwill and Other Intangible Assets - Schedule of Other Intangibles (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite lived intangible assets, gross carrying value	$ 86,341	$ 117,269
Accumulated amortization	(51,132)	(71,235)
Finite lived intangible assets, net carrying value	35,209	46,034
Indefinite lived intangible assets, gross carrying value	95	95
Total intangible assets, gross carrying value	86,436	117,364
Other intangible assets, net	35,304	46,129
Customer-Related Intangible Assets
Finite lived intangible assets, gross carrying value	84,878	115,806
Accumulated amortization	(49,782)	(70,090)
Finite lived intangible assets, net carrying value	35,096	45,716
Developed Technology Rights
Finite lived intangible assets, gross carrying value	1,463	1,463
Accumulated amortization	(1,350)	(1,145)
Finite lived intangible assets, net carrying value	$ 113	$ 318

Goodwill and Other Intangible Assets - Schedule of Estimated Future Amortization Expense Relating to Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
2018	$ 8,441
2019	6,132
2020	4,532
2021	4,082
2022	4,125
Thereafter	7,897
Finite lived intangible assets, net carrying value	$ 35,209	$ 46,034

Accrued Salaries and Benefits - Schedule of Accrued Salaries and Benefits (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Employee Related Liabilities Current [Abstract]
Accrued paid time off and leave	$ 11,904	$ 11,342
Accrued salaries	9,343	9,443
Accrued bonuses, liability-classified awards and commissions	16,909	13,025
Accrued payroll taxes and withholdings	2,557	1,948
Accrued medical	3,720	3,026
Other	1,212	979
Total accrued salaries and benefits	$ 45,645	$ 39,763

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued subcontractor and other direct costs	$ 47,508	$ 30,153
Deposits	6,641	12,389
Accrued IT and software licensing costs	2,261	5,349
Accrued taxes and insurance premiums	1,963	1,306
Accrued lease exit and facilities costs	1,591	77
Accrued interest	705	841
Accrued professional services	1,131	795
Other accrued expenses and current liabilities	3,280	1,721
Total accrued expenses and other current liabilities	$ 65,080	$ 52,631

Long-Term Debt - Additional Information (Details)		12 Months Ended
Long-Term Debt - Additional Information (Details)	May 11, 2017 USD ($) Bank	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Credit facility syndication, number of commercial banks \| Bank	11
Line of credit facility, expiration date		May 17, 2022
Line of credit facility, maximum borrowing capacity without borrowing base requirement	$ 600,000,000
Line of credit facility, accordion feature, additional revolving credit commitments under existing loan facility	300,000,000
New syndicated borrowings used to pay off or pay down borrowings from syndicate members	106,000,000
Line of credit facility, maximum borrowing capacity	$ 60,000,000
Line of credit facility, interest coverage ratio covenant	300.00%
Line of credit facility, leverage ratio covenant	375.00%
Line of credit facility, interest rate during period		0.15%	0.25%
Line of credit facility, remaining borrowing capacity		$ 390,000,000
Line of credit facility, current borrowing capacity		245,100,000
Debt issuance costs, net		6,900,000	$ 5,800,000
Accumulated amortization, debt issuance costs		4,700,000	4,500,000
Amortization of debt issuance costs		673,000	$ 532,000	$ 532,000
Debt issuance costs		$ 1,612,000		$ 17,000
Number of letters of credit, outstanding		12	9
Letters of credit outstanding, amount		$ 3,700,000	$ 3,400,000
Minimum
Debt Instrument [Line Items]
Line of Credit Facility, Committement Fee Unused Capacity		0.13%
Maximum
Debt Instrument [Line Items]
Line of Credit Facility, Committement Fee Unused Capacity		0.25%
Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.50%
London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.25%
London Interbank Offered Rate (LIBOR) \| Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.00%
London Interbank Offered Rate (LIBOR) \| Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.00%

Long-Term Debt - Schedule of Long-Term Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Debt Outstanding	$ 206,250	$ 259,389
Line of Credit
Debt Instrument [Line Items]
Debt Outstanding	$ 206,250	$ 259,389
Weighted Average Interest Rate	2.65%	2.46%

Derivative Instruments and Hedging Activities - Additional Information (Details) - USD ($)			12 Months Ended
	Aug. 31, 2017	Sep. 30, 2016	Dec. 31, 2017
Derivative [Line Items]
Net amount of realized gains and losses from hedge agreements			$ 700,000
Interest Rate Swap \| Cash Flow Hedging \| Designated as Hedging Instrument
Derivative [Line Items]
Aggregate notional amount	$ 25,000,000	$ 100,000,000
Derivative, Fixed Interest Rate	1.8475%
Beginning date of transaction	Aug. 31, 2018	Jan. 31, 2018
Derivative, maturity date	Aug. 31, 2023	Jan. 31, 2023

Income Taxes - Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Domestic	$ 69,347	$ 69,159	$ 54,150
Foreign	4,639	5,348	9,450
Income before income taxes	$ 73,986	$ 74,507	$ 63,600

Income Taxes - Income Tax Expense Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 12,995	$ 12,979	$ 14,797
State	3,243	3,514	2,669
Foreign	1,476	1,932	1,475
Total current	17,714	18,425	18,941
Deferred:
Federal	(9,425)	8,872	4,562
State	2,749	1,222	512
Foreign	72	(596)	216
Total deferred	(6,604)	9,498	5,290
Income tax expense	$ 11,110	$ 27,923	$ 24,231

Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets
Allowance for bad debt	$ 1,003	$ 1,008
Accrued paid time off	1,624	2,592
Accrued bonus		55
Foreign net operating loss (NOL) carry forward	1,301	1,371
Federal/state net operating loss (NOL) carry forward	507	3,010
Stock option compensation	2,726	4,292
Deferred rent	3,355	5,423
Deferred compensation	3,238	3,662
Foreign tax credits	505	2,631
Foreign exchange	2,051	5,349
Accrued liabilities and other	3,272	3,378
Deferred Tax Assets, gross, before valuation allowance	21,367	34,780
Less: Valuation Allowance	(1,636)	(1,131)	$ (933)	$ (542)
Total Deferred Tax Assets	19,731	33,649
Deferred Tax Liabilities
Retention	(1,375)	(1,684)
Prepaid expenses	(1,045)	(1,654)
Payroll taxes	(489)	(617)
Unbilled revenue	(5,407)	(8,728)
Depreciation	(4,773)	(6,664)
Amortization	(39,993)	(51,842)
Deferred gain and other		(1,574)
Total Deferred Tax Liabilities	(53,082)	(72,763)
Total Net Deferred Tax Liability	(33,351)	(39,114)
State and Local Jurisdiction
Deferred Tax Assets
Tax credits	$ 1,785	1,784
United States Government
Deferred Tax Assets
Tax credits		$ 225

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Income tax rate		35.00%	35.00%	35.00%
Provisional net tax benefit on re-measurement of deferred tax balances		$ 17,600,000
Provisional estimate of one-time transition tax liability for foreign subsidiaries, net of related foreign tax credits		1,400,000
Additional income taxes for remaining undistributed foreign earnings not subject to transition tax		$ 0
Operating loss carryforwards expiration term		20 years
Deferred tax assets, valuation allowance		$ 1,636,000	$ 1,131,000	$ 933,000	$ 542,000
Valuation allowance, deferred tax asset, increase (decrease), amount		505,000	198,000	391,000
Unrecognized tax benefits		820,000	1,185,000	$ 400,000	$ 702,000
Unrecognized tax benefits that would impact effective tax rate		700,000	1,000,000
Unrecognized tax benefits, income tax penalties and interest accrued		200,000	200,000
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit		$ 700,000
Earliest Tax Year \| Internal Revenue Service (IRS)
Income Taxes [Line Items]
Open tax year		2013
Earliest Tax Year \| State and Foreign Jurisdictions
Income Taxes [Line Items]
Open tax year		2013
Latest Tax Year \| Internal Revenue Service (IRS)
Income Taxes [Line Items]
Open tax year		2016
Latest Tax Year \| State and Foreign Jurisdictions
Income Taxes [Line Items]
Open tax year		2016
Foreign Tax Authority
Income Taxes [Line Items]
Operating loss carryforwards		$ 4,100,000	4,100,000
Deferred tax assets, valuation allowance		1,100,000	1,100,000
Valuation allowance, deferred tax asset, increase (decrease), amount		500,000
Domestic Tax Authority
Income Taxes [Line Items]
Operating loss carryforwards		$ 8,500,000
Net operating loss carry-forwards, expiration year		2034
State and Local Jurisdiction
Income Taxes [Line Items]
Tax credit carry-forward, amount		$ 2,800,000
Deferred tax assets, tax credit carry-forwards		$ 1,785,000	$ 1,784,000
State and Local Jurisdiction \| Earliest Tax Year
Income Taxes [Line Items]
Tax credit carry-forwards, expiration year		2017
State and Local Jurisdiction \| Latest Tax Year
Income Taxes [Line Items]
Tax credit carry-forwards, expiration year		2026
Scenario, Forecast
Income Taxes [Line Items]
Income tax rate	21.00%

Income Taxes - Unrecognized Tax Benefit Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, beginning balance	$ 1,185	$ 400	$ 702
Decrease attributable to settlements			(174)
Increase attributable to tax positions taken during a prior period		925	12
Decrease attributable to lapse of statute of limitations	(365)	(140)	(140)
Unrecognized tax benefits, ending balance	$ 820	$ 1,185	$ 400

Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Taxes at statutory rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	4.40%	3.90%	3.90%
Foreign tax rate differential	(0.30%)	(0.10%)	(0.30%)
Tax legislation	(22.60%)
Other permanent differences	0.70%	0.80%	1.90%
Prior year tax adjustments	(0.30%)	(1.00%)	(1.90%)
Unrecognized tax benefits	0.10%	1.00%
Valuation allowance	0.70%	(0.30%)
Equity-based compensation	(2.10%)	(1.00%)
Tax credits	(0.60%)	(0.80%)	(0.50%)
Taxes at effective rate	15.00%	37.50%	38.10%

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Foreign currency translation adjustments

$ 7,638

$ 11,815

Gain on sale of interest rate hedge agreement

^[1]

(2,158)

(2,175)

Change in fair value on derivative designated as cash flow hedge

^[2]

(441)

Total

$ 5,039

$ 9,640

[1]

[2]

Restricted Cash - Reconciliation of Cash and Cash Equivalents, and Restricted Cash to the Total Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Cash And Cash Equivalents [Abstract]

Cash and cash equivalents

$ 11,809

$ 6,042

$ 7,747

$ 12,122

Restricted cash - current

^[1]

11,191

Restricted cash - non-current

1,266

1,843

1,362

1,478

Total cash, cash equivalents, and restricted cash shown in the consolidated statement of cash flows

$ 24,266

$ 7,885

$ 9,109

$ 13,600

[1]	Restricted cash – current for the year ended December 31, 2017 represents amounts held in an escrow account for a future acquisition. See Note 19 – Subsequent Events.

Accounting for Stock-based Compensation - Additional Information (Details)		3 Months Ended	12 Months Ended
	Jun. 05, 2015 shares	Mar. 31, 2015 PerformancePeriod	Dec. 31, 2017 USD ($) PerformancePeriod $ / shares shares	Dec. 31, 2016 USD ($) PerformancePeriod shares	Dec. 31, 2015 USD ($) PerformancePeriod shares	Jun. 04, 2015 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, weighted average remaining contractual term			5 years
Performance based share awards, performance period			3 years
Share-based compensation arrangement by share-based payment award, options, vested in period, fair value \| $			$ 1,900,000	$ 1,300,000	$ 2,000,000
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, exercisable, weighted average remaining contractual term			5 years
Share-based compensation arrangement by share-based payment award, options, exercisable, weighted average remaining contractual term			5 years
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected forfeiture rate			1.86%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected forfeiture rate			19.51%
Options, Restricted Stock and RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant \| shares	5,966,186
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, weighted average remaining contractual term			10 years
Share-based compensation arrangement by share-based payment award, options, grants in period, gross \| shares			0	0	0
Share price \| $ / shares			$ 52.50
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value \| $			$ 4,500,000	$ 2,500,000	$ 800,000
Employee Stock Option \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			3 years
Employee Stock Option \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			4 years
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price \| $ / shares			$ 52.50
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value \| $			$ 6,300,000	7,200,000	6,300,000
Restricted Stock Units (RSUs) \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			3 years
Restricted Stock Units (RSUs) \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			4 years
Cash Settled RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			4 years
Share price \| $ / shares			$ 52.50
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value \| $			$ 6,900,000	$ 5,900,000	$ 2,900,000
Non-Employee Director Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee service share-based compensation, nonvested awards, compensation not yet recognized, share-based awards other than options \| $			$ 0
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price \| $ / shares			$ 52.50
Number of performance period in performance based share program \| PerformancePeriod		2	1	2	3
Percentage of multiplication award by product			2.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected dividend rate			0.00%	0.00%	0.00%
Share-based compensation arrangement by share-based payment award, fair Value assumptions, expected volatility rate			31.30%	30.90%	29.30%
Share-based compensation arrangement by share-based payment award, fair value assumptions, risk free interest rate			1.50%	1.00%	1.00%
Omnibus Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of additional shares authorized \| shares	1,540,000
Share-based compensation arrangement by share-based payment award, number of shares authorized \| shares	5,090,000					3,550,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant \| shares			1,900,000
Equivalent share deducted for every one share delivered	1.93

Accounting for Stock-based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Recognized	$ 17,544	$ 15,943	$ 14,741
Stock-Based Compensation Unrecognized	29,298
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Recognized	$ 164	909	1,546
Stock-Based Compensation Unrecognized Weighted- Average Period to Recognize (Year)	0 years
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Recognized	$ 7,080	6,325	7,409
Stock-Based Compensation Unrecognized	$ 12,659
Stock-Based Compensation Unrecognized Weighted- Average Period to Recognize (Year)	1 year 10 months 24 days
Cash Settled RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Recognized	$ 7,253	7,091	4,414
Stock-Based Compensation Unrecognized	$ 13,922
Stock-Based Compensation Unrecognized Weighted- Average Period to Recognize (Year)	1 year 10 months 24 days
Non-Employee Director Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Recognized	$ 671	741	645
Stock-Based Compensation Unrecognized Weighted- Average Period to Recognize (Year)	0 years
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-Based Compensation Recognized	$ 2,376	$ 877	$ 727
Stock-Based Compensation Unrecognized	$ 2,717
Stock-Based Compensation Unrecognized Weighted- Average Period to Recognize (Year)	1 year 6 months

Accounting for Stock-based Compensation - Outstanding Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding Ending Balance	411,498
Number of Shares, Exercisable at December 31, 2017	411,498
Weighted Average Exercise Price, Outstanding Ending Balance	$ 30.71
Weighted Average Exercise Price, Exercisable at December 31, 2017	$ 30.71
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding Beginning Balance	587,407	723,005	766,924
Number of Shares, Exercised	(175,909)	(128,301)	(43,919)
Number of Shares, Granted	0	0	0
Number of Shares, Forfeited/Expired		(7,297)
Number of Shares, Outstanding Ending Balance	411,498	587,407	723,005
Number of Shares, Vested plus expected to vest at December 31, 2017	411,498
Number of Shares, Exercisable at December 31, 2017	411,498
Weighted Average Exercise Price, Outstanding Beginning Balance	$ 29.56	$ 28.62	$ 28.20
Weighted Average Exercise Price, Exercised	26.84	23.65	21.23
Weighted Average Exercise Price, Forfeited/Expired		40.68
Weighted Average Exercise Price, Outstanding Ending Balance	30.71	$ 29.56	$ 28.62
Weighted Average Exercise Price, Vested plus expected to vest at December 31, 2017	30.71
Weighted Average Exercise Price, Exercisable at December 31, 2017	$ 30.71
Aggregate Intrinsic Value, Outstanding at December 31,2017	$ 8,965
Aggregate Intrinsic Value, Vested plus expected to vest at December 31, 2017	8,965
Aggregate Intrinsic Value, Exercisable at December 31, 2017	$ 8,965

Accounting for Stock-based Compensation - Stock Options Outstanding by Exercise Price Range (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	$ 21.77
Range of Exercise Prices, Upper range	$ 41.00
Number Outstanding \| shares	411,498
Weighted Average Remaining Contractual Term	5 years
Weighted Average Exercise Price	$ 30.71
Number Exercisable \| shares	411,498
Weighted Average Exercise Price	$ 30.71
Price Range 1
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	21.77
Range of Exercise Prices, Upper range	$ 25.00
Number Outstanding \| shares	62,917
Weighted Average Remaining Contractual Term	3 years 3 months 18 days
Weighted Average Exercise Price	$ 21.77
Number Exercisable \| shares	62,917
Weighted Average Exercise Price	$ 21.77
Price Range 2
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	25.01
Range of Exercise Prices, Upper range	$ 28.00
Number Outstanding \| shares	205,332
Weighted Average Remaining Contractual Term	4 years 9 months 18 days
Weighted Average Exercise Price	$ 26.50
Number Exercisable \| shares	205,332
Weighted Average Exercise Price	$ 26.50
Price Range 3
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	28.01
Range of Exercise Prices, Upper range	$ 40.68
Number Outstanding \| shares	143,249
Weighted Average Remaining Contractual Term	6 years 1 month 6 days
Weighted Average Exercise Price	$ 40.68
Number Exercisable \| shares	143,249
Weighted Average Exercise Price	$ 40.68

Accounting for Stock-based Compensation - Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Non-vested Beginning Balance	507,998	555,904	643,887
Number of Shares, Granted	194,227	240,868	250,159
Number of Shares, Vested	(179,974)	(221,659)	(233,899)
Number of Shares, Cancelled	(58,664)	(67,115)	(104,243)
Number of Shares, Non-vested Ending Balance	463,587	507,998	555,904
Number of Shares, expected to vest in the future	463,587
Weighted-Average Grant Date Fair Value, Non-vested Beginning Balance	$ 36.12	$ 35.40	$ 31.10
Weighted-Average Grant Date Fair Value, Granted	41.41	34.68	39.04
Weighted-Average Grant Date Fair Value, Vested	35.19	32.45	26.85
Weighted-Average Grant Date Fair Value, Cancelled	36.04	37.60	36.76
Weighted-Average Grant Date Fair Value, Non-vested Ending Balance	38.71	$ 36.12	$ 35.40
Weighted-Average Grant Date Fair Value, expected to vest in the future	$ 38.71
Aggregate Intrinsic Value, Non-vested	$ 24,338
Aggregate Intrinsic Value, expected to vest in the future	$ 24,338

Accounting for Stock-based Compensation - Cash-settled Restricted Stock Unit Activity (Details) - Cash Settled RSUs [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Non-vested Beginning Balance	463,022	446,663	537,119
Number of Shares, Granted	174,419	233,790	121,015
Number of Shares, Vested	(161,576)	(146,619)	(78,033)
Number of Shares, Cancelled	(83,949)	(70,812)	(133,438)
Number of Shares, Non-vested Ending Balance	391,916	463,022	446,663
Number of Shares, expected to vest in the future	391,916
Weighted-Average Grant Date Fair Value, Non-vested Beginning Balance	$ 35.96	$ 37.18	$ 36.36
Weighted-Average Grant Date Fair Value, Granted	42.06	34.29	39.35
Weighted-Average Grant Date Fair Value, Vested	40.78	34.70	33.29
Weighted-Average Grant Date Fair Value, Cancelled	36.43	37.55	38.14
Weighted-Average Grant Date Fair Value, Non-vested Ending Balance	38.80	$ 35.96	$ 37.18
Weighted-Average Grant Date Fair Value, expected to vest in the future	$ 38.80
Aggregate Intrinsic Value, Non-vested	$ 20,576,000
Aggregate Intrinsic Value, expected to vest in the future	$ 20,576,000

Accounting for Stock-based Compensation - Summary of Non-employee Director Awards Granted (Details) - Non-Employee Director Awards - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted	13,861	15,299	18,109
Weighted- Average Grant Date Fair Value	$ 48.41	$ 39.32	$ 35.62

Accounting for Stock-based Compensation - Summary of Performance Shares Activity (Details) - Performance Shares - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number ofShares
Number of Shares, Non-vested Beginning Balance	129,974	58,822
Number of Shares, Granted	60,929	74,574	58,822
Number of Shares, Cancelled	(3,881)	(3,422)
Number of Shares, Non-vested Ending Balance	187,022	129,974	58,822
Number of Shares, expected to vest in the future	126,846
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value, Non-vested Beginning Balance	$ 40.57	$ 44.21
Weighted-Average Grant Date Fair Value, Granted	38.81	37.75	$ 44.21
Weighted-Average Grant Date Fair Value, Cancelled	42.83	41.61
Weighted-Average Grant Date Fair Value, Non-vested Ending Balance	39.95	$ 40.57	$ 44.21
Weighted-Average Grant Date Fair Value, expected to vest in the future	$ 38.09
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Non-vested	$ 9,819
Aggregate Intrinsic Value, expected to vest in the future	$ 6,659

Earnings Per Share - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	142	163,564	167,849

Earnings Per Share - Schedule of Dilutive Effect of Stock Options RSUs and PSAs (Details) - shares

3 Months Ended

12 Months Ended

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

^[1]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Earnings Per Share [Abstract]

Basic weighted-average shares outstanding

18,646

18,666

18,775

18,972

18,988

18,965

19,008

18,994

18,766,000

18,989,000

19,335,000

Effect of potential exercise of stock options, RSUs, and performance shares

478,000

427,000

328,000

Diluted weighted-average shares outstanding

19,136

19,024

19,086

19,423

19,512

19,329

19,293

19,273

19,244,000

19,416,000

19,663,000

[1]	Includes adjustments for the adoption ASU 2016-09 in the second quarter of 2016.

Share Repurchase Program - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) shares	Nov. 04, 2017 USD ($)
Equity [Abstract]
Stock repurchase program, authorized amount	$ 75,000,000	$ 100,000,000
Line of credit facility, conditions for the elimination of limits on shares repurchases, leverage ratio	3.25
Stock Repurchased During Period, Shares \| shares	684,335
Stock Repurchased During Period, Value	$ 30,700,000
Stock repurchase program, remaining authorized repurchase amount	$ 100,000,000

Fair Value - Additional Information (Details) - Level 3 - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, measured at fair value on recurring basis	$ 0	$ 0
Liabilities, measured at fair value on recurring basis	$ 0	$ 0

Commitments and Contingencies - Additional Information (Details) $ in Thousands			94 Months Ended
	Aug. 31, 2017	Jun. 10, 2017 USD ($)	Dec. 31, 2017 USD ($) a	Mar. 08, 2010 ft²
Loss Contingencies [Line Items]
Community development related to claim			$ 220,200
Operating Leases, Future Minimum Payments Due			193,770
Minimum future sublease rentals			$ 1,400
Corporate Office Lease
Loss Contingencies [Line Items]
Operating Lease, Area of Leased Space \| ft²				258,000
Operating Lease, Additional Area of Leased Space \| a			72,000
Monthly Rent			$ 900
Percentage of Annual Escalations of Lease Rent			2.50%
Operating Leases, Future Minimum Payments Due			$ 150,600
Term of Lease	12 years
OCD vs ICF Emergency
Loss Contingencies [Line Items]
Loss contingency damages sought value		$ 200,800
Road Home Contract
Loss Contingencies [Line Items]
Contract term, period		3 years
Contract award, value		$ 912,000

Commitments and Contingencies - Future Minimum Rental Payments (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2018	$ 36,238
2019	34,223
2020	31,459
2021	31,091
2022	29,761
Thereafter	30,998
Total	$ 193,770

Commitments and Contingencies - Operating Lease Rent Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases Rent Expense [Abstract]
Rent	$ 36,269	$ 39,537	$ 40,009
Sublease income	(142)	(147)	(32)
Total rent expense	$ 36,127	$ 39,390	$ 39,977

Employee Benefit Plans - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Maximum defer of compensation subject to statutory limitations, percentage	70.00%
Percentage of employer matching contributions condition, one	100.00%
Percentage of employee entitled to employer matching contribution condition, one	3.00%
Percentage of employer matching contributions condition, two	50.00%
Percentage of employee entitled to employer matching contribution condition, two	2.00%
Defined contribution plan, employer discretionary contribution amount	$ 15,100,000	$ 14,900,000	$ 13,100,000
Deferred compensation arrangement with individual, cash awards granted, percentage	80.00%
Deferred compensation on performance bonuses that eligible employee, percentage	100.00%
Defined contribution plan, employers matching contribution, annual vesting percentage	100.00%
Employee stock purchase plan shares authorized	1,000,000
Employee stock purchase plan annual maximum payroll deduction	$ 25,000
Share-based compensation arrangement by share-based payment award, discount from market price, purchase date	5.00%
Stock issued during period, shares, employee stock purchase plans	27,285
Stock issued during period, value, employee stock purchase plans, per share	$ 47.34
Employee stock purchase plan, number of shares available for grant	724,826

Subsequent Events - Additional Information (Details) - Subsequent Event	Feb. 27, 2018 $ / shares
Subsequent Event [Line Items]
Dividend declaration date	Feb. 27, 2018
Cash dividend per share	$ 0.14
Dividend payment date	Apr. 16, 2018
Dividend close of record date	Mar. 30, 2018

Supplemental Information - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance For Doubtful Accounts Receivable Rollforward
Balance at beginning of period	$ 2,591	$ 2,138	$ 1,887
Bad debt expense	1,480	1,089	268
Write-offs, net of recoveries	(219)	(635)	(8)
Effect of foreign currency translation	1	(1)	(9)
Balance at end of period	$ 3,853	$ 2,591	$ 2,138

Supplemental Information - Schedule of Income Tax Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance [Abstract]
Balance at beginning of period	$ 1,131	$ 933	$ 542
Provision for income taxes - valuation allowance	505	198	391
Balance at end of period	$ 1,636	$ 1,131	$ 933

Selected Quarterly Financial Data (Unaudited)- Quarterly Financial Data (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

^[1]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

$ 321,174

$ 305,301

$ 306,392

$ 296,295

$ 289,559

$ 306,520

$ 305,419

$ 283,599

$ 1,229,162

$ 1,185,097

$ 1,132,232

Operating income

20,181

23,396

22,208

16,633

21,965

23,776

19,358

17,694

82,418

82,793

75,231

$ 27,070

$ 13,692

$ 11,937

$ 10,177

$ 12,673

$ 13,437

$ 10,583

$ 9,891

$ 62,876

$ 46,584

$ 39,369

Earnings per share:

$ 1.45

$ 0.73

$ 0.64

$ 0.54

$ 0.67

$ 0.71

$ 0.56

$ 0.52

$ 3.35

$ 2.45

$ 2.04

Weighted-average common shares outstanding (in thousands)

$ 1.41

$ 0.72

$ 0.63

$ 0.52

$ 0.65

$ 0.70

$ 0.55

$ 0.51

$ 3.27

$ 2.40

$ 2.00

18,646

18,666

18,775

18,972

18,988

18,965

19,008

18,994

18,766,000

18,989,000

19,335,000