Engility 10-K 9 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Mar. 06, 2017	Jul. 01, 2016
Document And Entity Information [Abstract]
Entity Registrant Name	Engility Holdings, Inc.
Entity Central Index Key	1,544,229
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	EGL
Amendment Flag	false
Entity Common Stock, Shares Outstanding		36,779,320
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 394,185,208

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 48,236	$ 30,022
Receivables, net	334,248	381,760
Prepaid income taxes	5,430	5,003
Assets held for sale, current	20,242
Other current assets	24,974	24,655
Total current assets	433,130	441,440
Property, plant and equipment, net	46,547	44,120
Goodwill	1,078,454	1,093,178
Identifiable intangible assets, net	393,891	436,627
Deferred tax assets	232,283	235,397
Assets held for sale	11,962
Other assets	2,292	3,211
Total assets	2,198,559	2,253,973
Current liabilities:
Current portion of long-term debt	26,947	8,447
Accounts payable, trade	43,943	54,345
Accrued employment costs	98,860	81,711
Accrued expenses	76,870	82,765
Advance payments and billings in excess of costs incurred	33,259	49,205
Deferred income taxes, current and income tax liabilities	209	695
Liabilities held for sale, current	4,341
Other current liabilities	36,410	36,293
Total current liabilities	320,839	313,461
Long-term debt	1,039,993	1,094,029
Income tax liabilities	64,852	68,000
Liabilities held for sale	1,084
Other liabilities	66,986	72,350
Total liabilities	1,493,754	1,547,840
Commitments and contingencies (Note 9)
Equity:
Preferred stock, par value $0.01 per share, 25,000 shares authorized, none issued or outstanding as of December 31, 2016 or 2015
Common stock, par value $0.01 per share, 175,000 shares authorized, 36,776 and 36,735 shares issued and outstanding as of December 31, 2016 and 2015, respectively	368	368
Additional paid-in capital	1,237,826	1,231,584
Accumulated deficit	(541,702)	(530,895)
Accumulated other comprehensive loss	(4,865)	(7,229)
Non-controlling interest	13,178	12,305
Total equity	704,805	706,133
Total liabilities and equity	$ 2,198,559	$ 2,253,973

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Preferred stock, par value (USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	25,000,000	25,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	175,000,000	175,000,000
Common stock, shares issued (shares)	36,776,000	36,735,000
Common stock, shares outstanding (shares)	36,776,000	36,735,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands	Nov. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue			$ 2,076,423,000	$ 2,085,623,000	$ 1,367,091,000
Costs and expenses
Cost of revenue			1,777,844,000	1,779,709,000	1,169,281,000
Selling, general and administrative expenses			166,238,000	203,262,000	114,890,000
Goodwill impairment	$ 0	$ 292,000,000	9,875,000	292,100,000
Total costs and expenses			1,953,957,000	2,275,071,000	1,284,171,000
Operating income (loss)			122,466,000	(189,448,000)	82,920,000
Interest expense, net			131,185,000	110,143,000	12,799,000
Other income (expenses), net			(80,000)	1,285,000	526,000
Income (loss) before income taxes			(8,799,000)	(298,306,000)	70,647,000
Provision (benefit) for income taxes			(2,730,000)	(68,067,000)	30,637,000
Net income (loss)			(6,069,000)	(230,239,000)	40,010,000
Less: Net income attributable to non-controlling interest			4,738,000	5,113,000	4,587,000
Net income (loss) attributable to Engility			$ (10,807,000)	$ (235,352,000)	$ 35,423,000
Earnings (loss) per share attributable to Engility
Basic			$ (0.29)	$ (7.02)	$ 2.07
Diluted			$ (0.29)	$ (7.02)	$ 1.97
Weighted average number of shares outstanding
Basic			36,730	33,536	17,100
Diluted			36,730	33,536	18,018

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (6,069)	$ (230,239)	$ 40,010
Other comprehensive income, net of tax:
Pension liability adjustment, net of tax expense (benefit) of $73, $531 and $(5,782) for the year ended December 31, 2016, 2015 and 2014, respectively	351	469	(9,018)
Less: reclassification adjustment for costs realized in net income, net of tax benefit of $114 and $123 for the year ended December 31, 2016 and 2015, respectively	(178)	(108)
Net pension liability adjustment	173	361	(9,018)
Unrealized gain on derivative instruments, net of tax expense of $2,880 and $2,250 for the year ended December 31, 2016 and 2015, respectively	4,514	3,526
Less: reclassification adjustment for costs realized in net income, net of tax benefit of $1,482 and $1,339 for the year ended December 31, 2016 and 2015, respectively	(2,323)	(2,098)
Net unrealized gain on derivative instruments	2,191	1,428
Other comprehensive income, net of tax	2,364	1,789	(9,018)
Comprehensive income (loss)	(3,705)	(228,450)	30,992
Less: Net income attributable to non-controlling interest	4,738	5,113	4,587
Comprehensive income (loss) attributable to Engility	$ (8,443)	$ (233,563)	$ 26,405

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Pension liability adjustment, tax expense (benefit)	$ 73	$ 531	$ (5,782)
Pension liability, reclassification adjustment, tax benefit	114	123
Unrealized gain on derivative instruments, tax expense	2,880	2,250
Unrealized gain on derivative instruments, reclassification adjustment, tax benefit	$ 1,482	$ 1,339

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]	Non-Controlling Interest [Member]
Beginning balance (in shares) at Dec. 31, 2013		17,238
Beginning Balance at Dec. 31, 2013	$ 443,154	$ 172	$ 761,119	$ (330,911)	$ 0	$ 12,774
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Engility	35,423			35,423
Other comprehensive income (loss), net	(9,018)				(9,018)
Share-based compensation (in shares)		272
Share-based compensation	8,833	$ 3	8,830
Proceeds from share-based payment arrangements (in shares)		82
Proceeds from share-based payment arrangements	1,480	$ 1	1,479
Payment of employee withholding taxes on restricted stock units	(2,371)		(2,371)
Excess tax deduction from share-based payment arrangements	1,707		1,707
Net income attributable to non-controlling member	4,587					4,587
Distribution to non-controlling interest member	(6,987)					(6,987)
Other	(55)		0	(55)		0
Ending balance (in shares) at Dec. 31, 2014		17,592
Ending Balance at Dec. 31, 2014	476,753	$ 176	770,764	(295,543)	(9,018)	10,374
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Engility	(235,352)			(235,352)
Other comprehensive income (loss), net	1,789				1,789
Shares issued for acquisition (in shares)		18,938
Shares issued for acquisition	663,125	$ 189	662,936
Option price adjustment	228		228
Transaction costs	(2,590)		(2,590)
Dividends paid or accrued, net of forfeitures	(206,839)		(206,839)
Share-based compensation (in shares)		186
Share-based compensation	9,300	$ 3	9,297
Proceeds from share-based payment arrangements (in shares)		19
Proceeds from share-based payment arrangements	279		279
Payment of employee withholding taxes on restricted stock units	(8,021)		(8,021)
Excess tax deduction from share-based payment arrangements	5,530		5,530
Net income attributable to non-controlling member	5,113					5,113
Distribution to non-controlling interest member	$ (3,182)					(3,182)
Ending balance (in shares) at Dec. 31, 2015	36,735	36,735
Ending Balance at Dec. 31, 2015	$ 706,133	$ 368	1,231,584	(530,895)	(7,229)	12,305
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Engility	(10,807)			(10,807)
Other comprehensive income (loss), net	2,364				2,364
Dividends forfeited	53		53
Share-based compensation (in shares)		17
Share-based compensation	8,255		8,255
Proceeds from share-based payment arrangements (in shares)		24
Proceeds from share-based payment arrangements	214		214
Payment of employee withholding taxes on restricted stock units	(1,779)		(1,779)
Excess tax deduction from share-based payment arrangements	(501)		(501)
Net income attributable to non-controlling member	4,738					4,738
Distribution to non-controlling interest member	$ (3,865)					(3,865)
Ending balance (in shares) at Dec. 31, 2016	36,776	36,776
Ending Balance at Dec. 31, 2016	$ 704,805	$ 368	$ 1,237,826	$ (541,702)	$ (4,865)	$ 13,178

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income (loss)	$ (6,069,000)	$ (230,239,000)	$ 40,010,000
Goodwill impairment charge	9,875,000	292,100,000
Share-based compensation	8,255,000	9,297,000	8,830,000
Depreciation and amortization	46,797,000	58,435,000	20,953,000
Loss on disposal of property, plant and equipment	1,078,000	3,413,000
Bad debt expense	744,000	7,346,000
Loss on extinguishment of debt	4,642,000
Amortization of bank debt fees	5,564,000	13,339,000	1,634,000
Deferred income taxes	1,256,000	(37,487,000)	(1,355,000)
Changes in operating assets and liabilities, excluding acquired amounts:
Receivables	31,882,000	46,338,000	43,115,000
Other assets	(986,000)	26,553,000	4,611,000
Accounts payable, trade	(9,673,000)	(33,570,000)	5,399,000
Accrued employment costs	17,149,000	(58,467,000)	(18,603,000)
Accrued expenses	1,805,000	(22,204,000)	3,004,000
Advance payments and billings in excess of costs incurred	(15,674,000)	8,901,000	2,904,000
Other liabilities	(2,240,000)	(35,337,000)	(8,143,000)
Net cash provided by operating activities	94,405,000	48,418,000	102,359,000
Investing activities:
Acquisitions, net of cash acquired		25,478,000	(207,250,000)
Capital expenditures	(21,446,000)	(19,610,000)	(5,436,000)
Net cash (used in) provided by investing activities	(21,446,000)	5,868,000	(212,686,000)
Financing activities:
Gross borrowings from issuance of long-term debt	1,180,000,000	585,000,000	75,000,000
Repayment of long-term debt	(1,215,754,000)	(403,674,000)	(13,750,000)
Gross borrowings from revolving credit facility	137,000,000	157,000,000	482,500,000
Repayments of revolving credit facility	(137,000,000)	(115,000,000)	(448,000,000)
Debt issuance costs	(9,988,000)	(42,425,000)	(1,131,000)
Equity issuance costs		(2,590,000)
Proceeds from share-based payment arrangements	214,000	279,000	1,479,000
Payment of employee withholding taxes on share-based compensation	(1,779,000)	(8,021,000)	(2,371,000)
Excess tax deduction on share-based compensation		5,530,000	1,707,000
Dividends paid	(1,709,000)	(204,304,000)
Distributions to non-controlling interest member	(3,865,000)	(3,182,000)	(6,987,000)
Net cash (used in) provided by financing activities	(52,881,000)	(31,387,000)	88,447,000
Change in cash from assets held from sale	(1,864,000)
Net change in cash and cash equivalents	18,214,000	22,899,000	(21,880,000)
Cash and cash equivalents, beginning of period	30,022,000	7,123,000	29,003,000
Cash and cash equivalents, end of period	48,236,000	30,022,000	7,123,000
Non-cash investing activity:
Fair value of equity consideration paid for acquisition		663,125,000
Supplemental cash flow disclosure:
Cash paid for taxes	1,071,000	4,866,000	20,256,000
Cash paid for interest	$ 106,205,000	$ 134,487,000	$ 11,470,000

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation Description of Business: Engility Holdings, Inc. (Engility) has provided mission critical services to the U.S. government for over six decades. Engility has a diversified portfolio that serves the U.S. Department of Defense (DoD), U.S. Department of Justice (DoJ), U.S. Department of State (DoS), Federal Aviation Administration (FAA), Department of Homeland Security (DHS), and space-related and intelligence community agencies, including the National Geospatial-Intelligence Agency (NGA), Defense Intelligence Agency (DIA), the National Reconnaissance Office (NRO), and National Aeronautical and Space Administration (NASA). As used herein, the terms “Engility,” the “Company,” “we,” “us” or “our” refers to (i) Engility and its subsidiaries, for all periods prior to the closing of the TASC, Inc. (TASC) acquisition, and (ii) New Engility and its subsidiaries, for all periods following the TASC acquisition. The TASC acquisition was effected through a new holding company named New East Holdings, Inc. (New Engility). As a result of the business combination, New Engility succeeded to and continues to operate, directly or indirectly, the existing business of Engility and, indirectly, acquired the existing business of TASC. As of December 31, 2016, we employed approximately 9,100 individuals globally and operated in 49 countries. We are led by a seasoned executive team, which is composed of industry, U.S. military and government veterans. We offer a broad range of services, including specialized technical consulting, program and business support, engineering and technology lifecycle support, information technology modernization and sustainment, supply chain services and logistics management and training and education to the U.S. government worldwide. Engility has no operations other than owning 100% of the capital stock of Engility Corporation (formerly TASC, Inc.), a Massachusetts corporation (Engility Corporation), and the consolidated financial statements of Engility and its consolidated subsidiaries are identical in all respects to the consolidated financial statements of Engility Corporation and its consolidated subsidiaries. On July 17, 2012, L-3 Communications Holdings, Inc. completed the spin-off of Engility Holdings, Inc. from L-3. We retained the systems engineering and technical assistance, training and operational support services businesses that were previously part of L-3’s Government Services segment. Unless the context indicates otherwise, (i) references to Engility, the Company, we, us or our refer to Engility Holdings, Inc. and its subsidiaries and (ii) references to L-3 refer to L-3 Communications Holdings and its subsidiaries. Summary of Significant Accounting Policies Principles of Consolidation and Combination and Basis of Presentation: The Consolidated Financial Statements are prepared in conformity with accounting principles generally accepted in the United States of America (U.S. GAAP) and reflect the financial position, results of operations and cash flows of Engility as a separate standalone entity. The Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. On January 31, 2014 and February 26, 2015, we completed the acquisitions of Dynamics Research Corporation (DRC) and TASC, respectively, which are more fully described in Note 3. These transactions were recorded using the purchase method of accounting; accordingly, DRC's and TASC's financial results are included in the Consolidated Financial Statements for the periods subsequent to the acquisition. Non-controlling Interest: Engility holds a 50.1% majority interest in Forfeiture Support Associates J.V. (FSA). The results of operations of FSA are included in Engility’s Consolidated Statements of Operations. The non-controlling interest reported on the Consolidated Balance Sheets represents the portion of FSA’s equity that is attributable to the non-controlling interest. Accounting Estimates: The preparation of financial statements in conformity with GAAP requires management to make estimates using assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. The most significant of these estimates include the recoverability, useful lives and valuation of identifiable intangible assets and goodwill, income taxes and contingencies. Actual results experienced by the Company may differ materially from management's estimates. Out-of-period adjustments: During 2016, the Company recorded out-of-period adjustments that decreased pre-tax income by $2 million to correct errors related to the year ended December 31, 2015. The adjustments were not material to 2016 or any previously issued financial statements. Revenue Recognition: Substantially all of the Company’s revenue is derived from services provided to the U.S. government and its agencies, primarily by the Company’s consulting staff and, to a lesser extent, subcontractors. The Company generates its revenue from the following types of contractual arrangements: cost-reimbursable-plus-fee contracts, time-and-materials contracts, and fixed-price contracts. Revenue on cost-reimbursable-plus-fee contracts is recognized as services are performed, generally based on allowable costs plus any recognizable earned fee. The Company considers fixed fees under cost-reimbursable-plus-fee contracts to be earned in proportion to the allowable costs incurred in performance of the contract. For cost-reimbursable-plus-fee contracts that include performance-based fee incentives, which are principally award fee arrangements, revenue and profit on award fees are recognized as work on the contracts is performed. We have significant history with the client for the majority of these contracts, and that history and management’s evaluation and monitoring of performance form the basis of estimated fees recorded. Estimates of the total fee to be earned are made based on contract provisions, prior experience with similar contracts or clients, and management’s evaluation of the performance on such contracts. Revenue for time-and-materials contracts is recognized as services are performed, generally on the basis of contract allowable labor hours worked multiplied by the contract-defined billing rates, plus allowable direct costs and indirect cost allocations associated with materials used and other direct expenses incurred in connection with the performance of the contract. Revenue on fixed-price contracts is recognized using a percentage-of-completion method based on actual costs incurred relative to total estimated costs for the contract. These estimated costs are updated during the term of the contract, and may result in revision by the Company of recognized revenue and estimated costs in the period in which they are identified by cumulative catch-up adjustments. Profits on fixed-price contracts result from the difference between incurred costs and revenue earned. Percentage-of-completion contract accounting requires significant judgment relative to assessing risks, estimating contract revenue and costs, and making assumptions for schedule and technical issues. Due to the size and nature of many of our contracts, developing total revenue and cost at completion estimates require the use of significant judgment. Contract costs include direct labor and billable expenses, an allocation of allowable indirect costs, and warranty obligations. Billable expenses are comprised of subcontracting costs and other direct costs that often include, but are not limited to, travel-related costs and telecommunications charges. We recognize revenue and billable expenses from these transactions on a gross basis. Assumptions regarding the length of time to complete the contract also include expected increases in wages and prices for materials. Estimates of total contract revenue and costs are monitored during the term of the contract and are subject to revision as the contract progresses. Anticipated losses on contracts are recognized in the period they are deemed probable and can be reasonably estimated. Anticipated contract losses recorded for the year ended December 31, 2016 and 2015 were $1 million and $2 million, respectively. Prior to January 1, 2015, the Company’s accounting policy was to record losses under contracts in accordance with ASC 605-10-S99 whereby losses were recorded over the contract life. For the year ended December 31, 2016, the recognized amounts related to changes in estimates at completion represented a net increase to revenue and operating income of $18 million, of which $4 million was directly related to favorable performance on contracts with award fees. Amounts related to changes in estimates at completion for the year ended December 31, 2015 represented a net increase to revenue and operating income of $10 million, of which $5 million was directly related to favorable performance on contracts with award fees. Prior to January 1, 2015, the Company’s accounting policy was to record revenue and operating income in accordance with ASC 605-10-S99 whereby award fees were recognized only when awarded by the customer. The Company’s contracts may include the delivery of a combination of one or more of the Company’s service offerings. In these situations, the Company determines whether such arrangements with multiple service offerings should be treated as separate units of accounting based on how the elements are bid or negotiated, whether the customer can accept separate elements of the arrangement, and the relationship between the pricing on the elements individually and combined. Included in unbilled receivables, a component of receivables, net, are certain restructuring costs related to the performance of our U.S. government contracts which are required to be recorded under GAAP but are not currently allocable to contracts. Such costs are expensed outside of our indirect rates and recognized as revenue for the portion we expect to be recoverable in our rates. At both December 31, 2016 and 2015 these receivables were approximately $11 million and are allocated to contracts when they are paid or otherwise agreed. We regularly assess the probability of recovery of these costs. This assessment requires us to make assumptions about the extent of cost recovery under our contracts and the amount of future contract activity. If the level of backlog in the future does not support the continued expensing of these costs, the profitability of our remaining contracts could be adversely affected. Revenue and profit in connection with contracts to provide services to the U.S. government that contain collection risk because the contracts are incrementally funded and subject to the availability of funds appropriated are deferred until a contract modification is obtained, indicating that adequate funds are available to the contract or task order. Cost of Revenue: Cost of revenue primarily consists of compensation expenses for program personnel, the fringe benefits associated with this compensation, other direct expenses incurred to complete programs, including cost of materials and subcontract efforts. Selling, General, and Administrative Expenses: Selling, general and administrative expenses are expensed as incurred. Share-Based Compensation: Certain key employees of Engility participate in share-based compensation plans. We follow the fair value based method of accounting for share-based employee compensation, which requires us to expense all share-based employee compensation. We issue performance shares, restricted stock units (RSUs) and non-qualified stock options under our existing plans to employees of the Company. Compensation expense is recognized for the entire award, net of estimated forfeitures, on a straight line basis over the requisite service period, which is generally three years, based on the grant date fair value. Income Taxes: We account for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are recorded for the future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a tax rate change on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. We record valuation allowances to reduce net deferred tax assets to the amount considered more likely than not to be realized. Changes in estimates of future taxable income can materially change the amount of such valuation allowances. We also recognize liabilities for uncertain tax positions when it is more likely than not that a tax position will not be sustained upon ultimate settlement with a taxing authority. If a tax position does not meet the “more-likely-than-not” recognition threshold, despite our belief that our filing position is supportable, the benefit of that tax position is not recognized. At December 31, 2016 and 2015, we had long-term net deferred tax assets of $232 million and $235 million, respectively. Deferred income taxes are determined separately for each of our tax-paying entities in each tax jurisdiction. In assessing the need for a valuation allowance, we considered all available positive and negative evidence, including the future reversal of existing temporary timing differences (deferred tax liabilities), taxable income in carryback years, the feasibility of tax planning strategies and estimated future taxable income. Positive evidence considered in connection with evaluating whether a valuation allowance is required includes the historic ability to utilize deferred tax assets before they expire and future forecasts. In order to realize the deferred tax assets, the Company needs to generate approximately $457 million of pre-tax income over the next 13 years. The Company believes this level of pre-tax income will be achievable. If management determines that a deferred tax asset is not “more likely than not” to be realized, a valuation allowance will be recorded through the income tax provision to reduce the deferred tax asset to an appropriate level in that period. On the basis of this evaluation, as of December 31, 2016, management has determined it is more likely than not a portion of state deferred tax assets, capital loss carryforwards, charitable donations, and foreign tax credits will not be realized and has recorded a $1 million valuation allowance against them. A change in the ability of our operations to continue to generate future taxable income could affect our ability to realize the future tax deductions underlying our deferred tax assets, and require us to provide a valuation allowance against our deferred tax assets. The recognition of a valuation allowance would result in a reduction to net income and, if significant, could have a material impact on our effective tax rate, results of operations and financial position in any given period. Cash and Cash Equivalents: Cash and cash equivalents represent cash that is directly attributable to the Company. Cash equivalents consist of highly liquid investments with an original maturity of three months or less at the time of purchase. Property, Plant and Equipment: Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is computed by applying the straight-line method to the estimated useful lives of the related assets. Useful lives for buildings are 30 years. Useful lives for leasehold improvements range from 5 to 23 years and useful lives for machinery, equipment, furniture and fixtures range from 3 to 10 years. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. When property or equipment is retired or otherwise disposed of, the net book value of the asset is removed from our balance sheet and the net gain or loss is included in the determination of operating income. Maintenance and repairs are charged to expense as incurred. Goodwill: We record goodwill in connection with the acquisition of businesses when the purchase price exceeds the fair values of the assets acquired and liabilities assumed. Generally, the largest intangible assets from the businesses that we acquire are the assembled workforces, which includes the human capital of the management, administrative, marketing and business development, engineering and technical employees of the acquired businesses. The success of our businesses, including our ability to retain existing business (revenue arrangements) and to compete successfully for and win new business (revenue arrangements), is primarily dependent on the management, marketing and business development, contracting, engineering and technical skills and knowledge of our employees, rather than on productive capital (plant and equipment, and technology and intellectual property). Additionally, for a significant portion of its businesses, our ability to attract and retain employees who have U.S. government security clearances, particularly those of top-secret and above, is critical to our success, and is often a prerequisite for retaining existing revenue arrangements and pursuing new ones. Therefore, because intangible assets for assembled workforces are part of goodwill in accordance with the accounting standards for business combinations, the substantial majority of the intangible assets for our business acquisitions are recognized as goodwill. Additionally, the value assigned to goodwill for our business acquisitions also includes the value that we expect to realize from cost reduction measures that we implement for our acquired businesses. The carrying value of goodwill is not amortized, but is tested for impairment annually as of November 30 as well as whenever events or changes in circumstances indicate that the carrying amount may not be recoverable using a two-step process for each reporting unit. A reporting unit is an operating segment, as defined by the segment reporting accounting standards, or a component of an operating segment. A component of an operating segment is a reporting unit if the component constitutes a business for which discrete financial information is available and is reviewed by operating segment management. Effective October 2016, we streamlined our structure from seven to five groups, each led by a senior vice president. We made this change to align more closely with our customers’ missions, increase customer intimacy, and eliminate overlap and redundancy. Upon our realignment, the Company combined the goodwill of the units that were consolidated. During 2015, goodwill was allocated to seven reporting units. Upon our acquisition of TASC in February 2015, the Company allocated the goodwill to each of our seven reporting units using relative fair value. Relative fair value was determined based on each reporting unit’s expected contribution to the Company’s projected earnings before interest and taxes (EBIT). The Company does not aggregate any reporting units when evaluating goodwill for impairment. The first step in the process is to identify any potential impairment by comparing the carrying value of a reporting unit including goodwill and its fair value. We determine the fair value of the reporting units using a hybrid method valuation approach which includes (1) the Income Approach (also referred to as a discounted cash flow or DCF), and (2) the Guideline Public Company Method. If a potential impairment is identified, the second step is to measure the impairment loss by comparing the implied fair value of goodwill with the carrying value of goodwill of the reporting units. Identifiable Intangible Assets: As part of the accounting for our business acquisitions, identifiable intangible assets are recognized as assets if they arise from contractual or other legal rights, or if they are capable of being separated or divided from the acquired business and sold, transferred, licensed, rented or exchanged. We do not recognize any intangible assets apart from goodwill for the assembled workforces of our business acquisitions. Identifiable intangible assets include customer contractual relationships, contractual backlog and technology. The initial measurement of these intangible assets is based on their fair values. The most significant identifiable intangible asset that is separately recognized for our business acquisitions is customer contractual relationships. All of our customer relationships are established through written customer contracts (revenue arrangements). The fair value for customer contractual relationships is determined, as of the date of acquisition, based on estimates and judgments regarding expectations for the estimated future after-tax earnings and cash flows (including cash flows for working capital) arising from the follow-on revenue on contract (revenue arrangement) renewals expected from the customer contractual relationships over their estimated lives, including the probability of expected future contract renewals and revenue, less a contributory assets charge, all of which is discounted to present value. Identifiable intangible assets are: (1) tested for impairment whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable and (2) amortized over their estimated useful lives as the economic benefits are consumed, ranging from 1 to 20 years. We evaluate the carrying amount and the remaining useful lives of identifiable intangible assets on a quarterly basis at the asset group level. To the extent events or changes in circumstances indicate the carrying amount of these assets may not be recoverable, we test recoverability based on our projection of the undiscounted future operating cash flows of the related asset group. To the extent such projections indicate that future undiscounted cash flows are not sufficient to recover the carrying amount, we recognize a non-cash impairment charge to reduce the carrying amount to fair value. No impairment charges related to identifiable intangible assets were recorded in the three years ending December 31, 2016. To evaluate the reasonableness of the useful lives of the identifiable intangible assets on a quarterly basis, the Company considers whether there have been any significant changes to the nature of the customer contractual relationships, including customers served by Engility, contract types and nature of work performed, subsequent to the date the intangibles were acquired. Assets and Liabilities Held for Sale: The Company entered into two separate agreements during the second half of 2016 to sell certain assets and liabilities owned by the Company both of which were completed in the first quarter of 2017. Depreciation for these assets ceased on the date they were designated as held for sale. The held for sale assets and liabilities were recorded at the lower of carrying value or estimated fair value, less an estimate of costs to sell. The estimate of fair value included unobservable inputs (Level 3 fair value). These assets and liabilities were designated as assets held for sale and liabilities held for sale in the accompanying consolidated balance sheets as of December 31, 2016. During the fourth quarter of 2016, the Company agreed to sell certain assets and liabilities of its wholly-owned subsidiary, International Resources Group Ltd. (IRG). The Company completed its sale of IRG on January 6, 2017 which is more fully described in Note 15. In connection with the sale of IRG, and based on the final selling price of the business being less than carrying value of the assets as of December 31, 2016, the Company recorded a non-cash goodwill impairment charge of $10 million in 2016. During the third quarter of 2016, the Company agreed to sell certain long-term assets and designated $2 million as assets held for sale, current, from property, plant and equipment, net, on the Company's consolidated balance sheet at . The carrying amounts of assets and liabilities that were classified as held for sale at December 31, 2016 were as follows: Assets held for sale, current: Cash and cash equivalents $ 1,864 Receivables, net 14,886 Other current assets 3,492 Assets held for sale, current $ 20,242 Assets held for sale: Property, plant and equipment, net $ 868 Goodwill 4,849 Identifiable intangible assets, net 6,245 Assets held for sale $ 11,962 Liabilities held for sale, current: Accounts payable, trade $ 727 Accrued expenses 3,268 Advance payments and billings in excess of costs incurred 271 Other current liabilities 75 Liabilities held for sale, current $ 4,341 Liabilities held for sale: Other liabilities $ 1,084 Liabilities held for sale $ 1,084 Accounts Payable: Accounts payable for the periods as of December 31, 2016 and 2015 includes $3 million and $26 million, respectively, for which payment has been remitted to the vendor, but the checks remain outstanding. Pension and Defined Benefit Plans: The Company measures plan assets and benefit obligations as of the date of its fiscal year end. Accounting and reporting for the Company's pension and defined benefit plans requires the use of assumptions, including but not limited to, a discount rate and an expected return on assets. These assumptions are reviewed at least annually based on reviews of current plan information and consultation with the Company's independent actuary and the plans’ investment advisor. If these assumptions differ materially from actual results, the Company's obligations under the pension and defined benefit plans could also differ materially, potentially requiring the Company to record an additional liability. The Company's pension and defined benefit plan liabilities are developed from actuarial valuations, which are performed each year. Derivative Instruments: The Company recognizes derivative instruments as either an asset or liability measured at its fair value. For derivative instruments that have been formally designated as a cash flow hedge, the effective portion of changes in the fair value of the derivative instruments are recorded in accumulated other comprehensive income (loss). Amounts in accumulated other comprehensive income (loss) are reclassified into earnings when interest expense on the underlying borrowings is recognized. The Company had entered into multiple interest rate swap contracts which reduced the exposure to variability in cash flows relating to interest payments on a portion of its outstanding debt payments. These interest rate contracts were designated as cash flow hedges. The effective portion of the derivative’s gain or loss was initially reported in accumulated other comprehensive income (loss) and would be subsequently reclassified into earnings in the same period or periods during which the hedged forecasted transaction affects earnings. The ineffective portion of the gain or loss of a cash flow hedge would be reported in earnings. Fair Value Measurements: The Company utilizes fair value measurement guidance prescribed by GAAP to value its financial instruments. The guidance includes a definition of fair value, prescribes methods for measuring fair value, establishes a fair value hierarchy based on the inputs used to measure fair value and expands disclosures about the use of fair value measurements. Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, which are typically based on an entity’s own assumptions, as there is little, if any, related market activity. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. The carrying values of cash and cash equivalents, contract receivables and accounts payable approximate fair value because of the short-term nature of these instruments. The carrying value of the Term Loans, excluding original issue discount, and Notes approximated their fair value at December 31, 2016. The fair value of the Term Loans and Notes are based on quotes from a nationally recognized fixed income trading platform and is considered to be a Level 2 input, measured under GAAP hierarchy. Earnings per Share: Basic EPS is computed by dividing net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted EPS reflects the weighted-average effect of all potentially dilutive securities outstanding during the periods. Diluted EPS includes the incremental effect of the employee stock purchase plan, restricted stock units, and stock options calculated using the treasury stock method. For the years ended December 31, 2016, 2015 and 2014, 766,935 shares, 570,181 shares and 0 shares, respectively, of common stock were not included in diluted EPS due to their anti-dilutive effects. The following table sets forth the reconciliation of the weighted average shares outstanding and calculation of EPS: Year Ended December 31, 2016 2015 2014 Net income (loss) attributable to Engility $ (10,807 ) $ (235,352 ) $ 35,423 Weighted average number of shares outstanding – Basic 36,730 33,536 17,100 Dilutive effect of share-based compensation outstanding after application of the treasury stock method — — 918 Weighted average number of shares outstanding – Diluted 36,730 33,536 18,018 Earnings (loss) per share attributable to Engility Basic $ (0.29 ) $ (7.02 ) $ 2.07 Diluted $ (0.29 ) $ (7.02 ) $ 1.97

New Accounting Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
New Accounting Pronouncements	2. New Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test of Goodwill Impairment, In November 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-18, Restricted Cash—a consensus of the FASB Emerging Issues Task Force In August 2016, the FASB issued Accounting Standards Update ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) In April 2016, the FASB issued ASU No. 2016-10 , Identifying Performance Obligations and Licensing In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting. In February 2016, the FASB issued ASU No. 2016-02, Leases In April 2015, the FASB issued ASU No. 2015-03, Interest—Imputation of Interest Interest—Imputation of Interest: Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements - Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In June 2014, the FASB issued ASU No. 2014-12, Compensation - Stock Compensation (Topic 718)—Accounting for Share-based Payments when Terms of an award Provide That a Performance Target Could be Achieved after the Requisite Service Period In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) Principal versus Agent Considerations (Reporting Revenue Gross Versus Net) , Identifying Performance Obligations and Licensing Revenue from Contracts with Customers – Narrow Scope Improvements and Practical Expedients Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers

Business Acquisitions

Business Acquisitions	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Business Acquisitions	3. Business Acquisitions TASC Acquisition On February 26, 2015, we completed the acquisition of TASC, a leading professional services provider to the national security and public safety markets, in an all-stock transaction. We acquired TASC to further diversify our portfolio to add leading positions with U.S. national security and public safety agency customers, including, the NGA, DIA and other intelligence community agencies. We also added space-related agency customers such as the NRO, NASA and U.S. Air Force. The acquisition of TASC also enhanced our market position with DHS, DTRA, FAA, and MDA. TASC had approximately 4,000 employees located throughout the United States as of February 26, 2015. The business combination was effected through New Engility. As a result of the business combination, New Engility succeeded to and continues to operate, directly or indirectly, the existing business of Engility and, indirectly, acquired the existing business of TASC. Accordingly, the combined companies now operate under New East Holdings, Inc. which was renamed “Engility Holdings, Inc.” upon the closing of the acquisition. The New Engility common stock, similar to the predecessor Engility common stock, trades on the New York Stock Exchange (NYSE) under the symbol “EGL.” As a result of the acquisition of TASC, former TASC stockholders now hold approximately 51% of our shares of common stock outstanding as of March 6, 2017. As a condition to the merger, we entered into a Stockholders Agreement, dated February 26, 2015, with Birch Partners, LP (Birch), and for the limited purposes set forth therein, certain investment funds affiliated with Kohlberg Kravis Roberts & Co. L.P. (KKR) and certain investment funds affiliated with General Atlantic LLC (GA) (the Stockholders Agreement). The Stockholders Agreement establishes certain rights, restrictions and obligations of Birch, KKR and GA, and sets forth certain governance and other arrangements relating to Engility, including the right of Birch to designate (i) four directors for nomination to our board of directors for so long as each of KKR and GA (including their respective affiliates) beneficially own at least 50% of the shares of our common stock it owned as of the date of the Stockholders Agreement or (ii) two directors for nomination to our board of directors for so long as each of KKR and GA (including their respective affiliates) beneficially own at least 25% (but less than 50%) of the shares of our common stock it owned as of the date of the Stockholders Agreement. In connection with the acquisition, we issued 18,937,765 shares of Engility common stock on February 26, 2015 valued at approximately $663 million, and we assumed debt with an estimated fair value of $623 million. Engility declared a special cash dividend payable to stockholders of record as of immediately prior to the closing of the TASC transaction (the Cash Dividend), including holders of all outstanding RSUs and performance shares upon vesting, in the amount of $207 million, or $11.434 per share. For holders of unvested RSUs and performance shares, the Cash Dividend accrued on such grants and will be delivered to the holders upon the vesting of such grants. In connection with the acquisition, Engility has paid $204 million pursuant to the Cash Dividend to stockholders and holders of vested RSUs and options. The remaining Cash Dividend balance will be paid to holders upon the vesting of their outstanding RSUs and performance shares. We accounted for the acquisition of TASC as a business combination under ASC 805 with Engility as the accounting acquirer. We determined Engility was the accounting acquirer in accordance with ASC 805-10-25-5 as Engility gained control of TASC upon completion of the merger. To make this determination we considered factors as indicated in ASC 805-10-55, including which entity issued equity interests to effect the combination, board of director composition, stockholder ownership, voting control, restrictions on stockholder voting rights, anticipated management positions and the relative size of the two companies. Engility issued its equity to effect the combination, which is usually done by the acquirer. The board of directors immediately following the acquisition was comprised of eleven individuals, seven of whom were the Engility directors and the remaining four of whom were designated by Birch the holder of approximately 99% of the outstanding common stock of TASC Parent Corporation prior to the acquisition. While the stockholders of TASC Parent Corporation own approximately 52% of the combined company common stock following the closing of the transaction, Birch executed, at the closing of the transaction, a stockholders agreement agreeing to vote (i) until it no longer has any director nomination rights, with respect to the election of directors, all of its shares in the same manner as, and in the same proportion to, all shares as voted by Engility stockholders (excluding the votes of Birch), other than with respect to its four director nominees; and (ii) with respect to all other proposals, all of its shares in excess of 30% of the total voting power of all issued and outstanding shares of the combined company (between 21% and 21.5% initially) in the same manner as, and in the same proportion to, all shares as voted by Engility stockholders (excluding the votes of Birch). Thus, with respect to proposals other than the election of directors, Birch only controls and is able to independently vote an aggregate of 30% of the outstanding shares of the combined company. Birch is not be able to transfer ownership for years one through three following the closing of the transaction and is limited in years four through six. Following the acquisition, the combined Engility company was led by Engility’s legacy President and Chief Executive Officer, Anthony Smeraglinolo, and John Hynes, TASC’s former President and Chief Executive Officer, became the Chief Operating Officer of the combined company, reporting to Mr. Smeraglinolo. Another consideration was the relative size of the two companies. Engility had greater revenue, total assets, earnings before interest, taxes, depreciation, and amortization (EBITDA), pre-tax income and employees. All of the above mentioned factors have led us to conclude that Engility was the accounting acquirer. The final allocation of purchase price is as follows: Number of Engility shares issued 18,937,765 Share price on February 26, 2015 $ 46.45 Dividend payable to Engility stockholders 11.434 Value of Engility shares issued to TASC stockholders $ 35.016 Equity consideration $ 663,125 Cash $ 25,478 Receivables 149,041 Prepaid and deferred income taxes, current 26,015 Other current assets 26,286 Property, plant and equipment 15,835 Deferred tax assets 175,180 Other assets 5,096 Current portion of long-term debt (4,097 ) Accounts payable, trade (34,503 ) Accrued employment costs (92,396 ) Accrued expenses (33,387 ) Advance payments and billings in excess of costs incurred (18,004 ) Deferred income taxes, current and income taxes payable (248 ) Other current liabilities (32,522 ) Long-term debt (619,227 ) Other long-term liabilities (24,446 ) Identifiable intangible assets 358,300 Goodwill 740,724 $ 663,125 The goodwill arising from the TASC acquisition consists largely of the specialized nature of the workforce as well as the synergies and economies of scale expected from combining the operations of Engility and TASC and their respective subsidiaries. The goodwill arising from the TASC acquisition is not tax deductible. The valuation of the identified intangible assets acquired is summarized below: Useful Life (years) Customer contractual relationships 15 $ 333,600 Contractual backlog 1 17,700 Technology 15 7,000 Total intangible assets $ 358,300 From the date of acquisition, February 26, 2015, through December 31, 2015, TASC generated $907 million of revenue and operating income of $55 million. Acquisition and restructuring expenses related to our acquisition of TASC and DRC for the year ended December 31, 2016, 2015 and 2014 were $12 million, $45 million and $18 million, respectively. Amortization expense related to the acquisitions of TASC and DRC for the year ended December 31, 2016, 2015 and 2014 were $28 million, $36 million and $6 million, respectively. DRC Acquisition On January 31, 2014, we completed the acquisition of DRC pursuant to a definitive agreement dated December 20, 2013. We paid $11.50 per share for DRC, for an aggregate purchase price of approximately $207 million in cash (including the retirement of approximately $86 million of debt of DRC). As a result of the acquisition, DRC is now a wholly-owned subsidiary of Engility. DRC was a leading provider of innovative management consulting, engineering, technical, information technology services and solutions to Federal and state governments. Founded in 1955 and headquartered in Andover, Massachusetts, DRC had approximately 1,100 employees located throughout the United States as of December 31, 2013. We acquired DRC to create a stronger, more efficient organization to support our customers with a wider range of specialized technology and mission expertise. This acquisition is consistent with our strategy to expand our addressable market, customer base and capabilities. In addition, it increased our access to additional key contract vehicles, added scale to our business and further diversified our revenue base. The goodwill arising from the DRC acquisition of $167 million consists largely of the specialized nature of the workforce as well as the synergies and economies of scale expected from combining the operations of Engility and DRC and its subsidiaries. The goodwill arising from the DRC acquisition is not tax deductible. From the date of acquisition through December 31, 2014, DRC generated $218 million of revenue and pre-tax net income of $9 million. DRC's pre-tax net income includes the impact of $6 million of amortization of customer contracts and customer relationships, as well as $8 million in expenses associated with severance and integration-related costs. Pro forma Results The following pro forma results of operations have been prepared as though the acquisition of TASC had occurred on January 1, 2014. These pro forma results include adjustments for (i) amortization expense for the estimated identifiable intangible assets in the preliminary allocation of purchase price, (ii) the removal of historical TASC amortization expense, (iii) adjustments to conform TASC policies to Engility's policies related to the timing and recognition of certain contract revenue and costs, (iv) the alignment of TASC’s financial calendar to that of Engility’s and (v) the removal of acquisition-related expenses incurred and recorded in each of TASC and Engility’s results of operations in the year ended December 31, 2015, and a related adjustment to record such costs in the year ended December 31, 2014. The pro forma results of operations also include adjustments to reflect the acquisition of DRC as though the acquisition occurred on January 1, 2013. These pro forma results include adjustments for (i) amortization expense for the identifiable intangible assets in the final purchase price allocation, (ii) the removal of historical DRC amortization expense, and (iii) the removal of acquisition-related expenses incurred and recorded on each of DRC and Engility’s results of operations in the year ended December 31, 2014. The following pro forma results do not purport to be indicative of the results of operations that would have been attained had the TASC and DRC acquisitions been made as of January 1, 2015 and 2014, respectively, or of results of operations that may occur in the future. Years Ended December 31, 2015 2014 Revenue $ 2,239,577 $ 2,497,428 Operating (loss) income $ (143,496 ) $ 76,495

Receivables

Receivables	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Receivables	4. Receivables Substantially all of our receivables relate to contracts with the U.S. government and prime contractors or subcontractors of the U.S. government. Revenue from the U.S. government under prime contracts and subcontracts, as compared to total revenue, was approximately 99%, 99% and 98%, for the years ended December 31, 2016, 2015 and 2014, respectively. The components of contract receivables are presented in the table below. December 31, 2016 2015 Billed receivables $ 97,661 $ 229,358 Unbilled receivables 248,253 163,882 Allowance for doubtful accounts (11,666 ) (11,480 ) Total receivables, net $ 334,248 $ 381,760 The billed receivables at December 31, 2015 reflect a one week acceleration of our billing cycle to invoice contractually billable work in anticipation of the consolidation of our financial systems in early January 2016. This resulted in an increase in our billed receivables, with a corresponding decrease in our unbilled receivables, of approximately $110 million. The balances as of December 31, 2016 reflect a return to our normal billing cycles. Unbilled receivables principally consist of amounts to be billed within the next month, generally from cost-plus type contracts and time-and-material type contracts due to the timing of preparation of invoices to customers. Revenue recorded in excess of milestone billings on fixed-price type contracts consist of amounts not expected to be billed within the next month. Such amounts are converted to billed receivables when invoiced to customers according to contractual billing terms, which generally occur when performance milestones are completed. We believe that significantly all of the unbilled contract receivables at December 31, 2016 will be billed and collected within one year. We do not believe that we have significant exposure to credit risk as accounts receivable and the related unbilled amounts are due primarily from the U.S. government. The Company has credit risk with respect to foreign government customers which comprise approximately 1% of total receivables and has reserved for these balances accordingly. The allowance for doubtful accounts primarily represents our estimate for exposure to compliance, contractual issues and bad debts related to prime contractors and commercial customers. The following table details the allowance for doubtful accounts: Year Ended December 31, 2016 2015 2014 Balance at beginning of year $ 11,480 $ 1,482 $ 1,410 Charged to expense 744 10,286 441 Deductions (558 ) (288 ) (369 ) Balance at end of year $ 11,666 $ 11,480 $ 1,482 The increase in the allowance for doubtful accounts from fiscal year 2014 to 2015 was primarily driven by a reserve booked related to a dispute with a foreign government customer.

Goodwill and Identifiable Intan

Goodwill and Identifiable Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Identifiable Intangible Assets	5. Goodwill and Identifiable Intangible Assets The changes in the carrying amounts of goodwill were as follows: Balance as of January 1, 2015 Goodwill $ 1,319,590 Accumulated impairment losses (675,036 ) 644,554 TASC acquisition 740,724 Impairment charge (292,100 ) Balance as of December 31, 2015 Goodwill 2,060,314 Accumulated impairment losses (967,136 ) 1,093,178 Impairment charge (9,875 ) Goodwill allocated to assets held for sale (4,849 ) Balance as of December 31, 2016 Goodwill 2,055,465 Accumulated impairment losses (977,011 ) $ 1,078,454 Goodwill Impairment Review We review goodwill for impairment annually as of November 30 and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable using a two-step process for each reporting unit. The first step in the process is to identify any potential impairment by comparing the carrying value of a reporting unit including goodwill and its fair value. We use a hybrid method valuation approach to determine the fair value of the reporting units which includes (1) the Income Approach (also referred to as a discounted cash flow or DCF), which is dependent upon estimates for future revenue, operating income, depreciation and amortization, income tax payments, working capital changes, and capital expenditures, as well as, expected long-term growth rates for cash flows; and (2) the Guideline Public Company Method, which uses valuation metrics from similar publicly traded companies (i.e., small-to-mid-cap providers of services to the U.S. Federal and local governments). Both of these approaches are affected by economic conditions related to the U.S. defense industry as well as conditions in the U.S. capital markets. We evaluate the reasonableness of the fair value calculations of our reporting units by comparing the total of the fair values of all of our reporting units to our total market capitalization, taking into consideration an appropriate control premium. If a potential impairment is identified, the second step is to measure the impairment loss by comparing the implied fair value of goodwill with the carrying value of goodwill of the reporting unit. The fair value measurement was calculated using unobservable inputs to the discounted cash flow method, which are classified as Level 3 within the fair value hierarchy under GAAP. The key assumptions we used to estimate the fair values of the reporting units are: • Discount rates; • Compounded annual revenue growth rates; • Average operating margins; and • Terminal value capitalization rate (capitalization rate). • Guideline Company valuations Of the key assumptions, the discount rates and the capitalization rate are market-driven. These rates are derived from the use of market data and employment of the capital asset pricing model. The company-dependent key assumptions are the compounded annual revenue growth rates and the average operating margins and are subject to much greater influence from our actions. We used discount rates that are commensurate with the risk and uncertainty inherent in the respective reporting units and in our internally-developed forecasts. Actual results may differ from those assumed in our forecasts and changes in assumptions or estimates could materially affect the determination of the fair value of a reporting unit, and therefore could affect the amount of potential impairment. We evaluate the reasonableness of the fair value calculations of our reporting units by reconciling the total of the fair values of all of our reporting units to our total market capitalization as of our impairment test date, taking into account an appropriate control premium. The determination of a control premium requires the use of judgment and is based upon control premiums observed in comparable market transactions. Inherent in our development of the present value of future cash flow projections are assumptions and estimates derived from a review of our expected revenue growth rates, profit margins, business plans, cost of capital, and tax rates. We also make assumptions about future market conditions, market prices, interest rates, and changes in business strategies. Changes in our assumptions or estimates could materially affect the determination of the fair value of a reporting unit and, therefore, could eliminate the excess of fair value over the carrying value of a reporting unit entirely and, in some cases, could result in impairment. Such changes in assumptions could be caused by a loss of one or more significant contracts, reductions in government and/or private industry spending, or a decline in the demand of our services due to changing economic conditions. Given the contractual nature of our business, if we are unable to win or renew contracts; are unable to estimate and control our contract costs; fail to perform adequately to our clients’ expectations; fail to procure third-party subcontractors, or fail to secure adequate funding for our projects, our profits, revenue and growth over the long-term would decline and such a decline could significantly affect the fair value assessment of the reporting units and cause our goodwill to become impaired. To determine fair value as of November 30, 2016 and 2015, we used the Income Approach and Guideline Public Company Method weighted 50% and 50%, respectively. The two methods returned value indications that were supportive of one another and corroborative of the value conclusion. Our chief operating decision maker receives and evaluates consolidated financial information in order to allocate resources and assess performance. As a result, we determined that we have a single operating and reportable segment and consequently do not aggregate any operating segments. Goodwill Impairment Measurement Based on results of the November 30, 2016 goodwill impairment test, the fair value for all five reporting units exceeded their carrying value; therefore, no impairment charge was required. However, in connection with the sale of IRG, and based on the final selling price of the business being less than carrying value of the assets as of December 31, 2016, the Company recorded a non-cash goodwill impairment charge of $10 million in 2016. During the fourth quarter of 2015, we recorded a goodwill impairment charge of $292 million due to the decline in the estimated fair value in four of the reporting units. The decline in the estimated fair value was primarily due to the continued impact from legacy contracts that are ending, reduced in-theater work, new business that did not materialize in the fourth quarter of 2015 and a corresponding reduction in estimated future cash flows. The more significant assumptions used in our DCF valuation to determine the fair value of the seven reporting units in connection with the goodwill valuation assessment at November 30, 2016 and 2015 were: (1) detailed three-year cash flow projections for the reporting units, which are based primarily on our estimates of future revenue, operating income and cash flows, (2) an expected long-term growth rate for the reporting units which reflects the expected long-term growth rate for the U.S. economy and respective areas of the U.S. defense industry in which the reporting units operate and (3) risk adjusted discount rates, which represents the estimated weighted-average cost of capital (WACC) for the reporting units and includes the estimated risk-free rate of return that is used to discount future cash flow projections to their present values. The reporting units WACC was comprised of were: (1) an estimated required rate of return on equity based on publicly traded companies with business and economic risk characteristics comparable to the reporting units (Market Participants) and (2) an after-tax rate of return on Market Participants’ debt, each weighted by the relative percentages of Market Participants’ equity and debt. The WACC is based on a number of market inputs that are outside of our control and are updated annually to reflect changes to such market inputs as of the date of our annual goodwill impairment assessments, including changes to: (1) the estimated required rate of return on equity based on historical returns on common stock securities of Market Participants and the Standard & Poor’s 500 Index (referred to as beta), (2) the risk free rate of return based on the prevailing market yield on the 20-year U.S. Treasury bond, (3) the Moody’s 20 year Baa rate, and (4) the relative percentages of Market Participants’ equity and debt. We consistently consider several factors to determine expected future annual cash flows for the reporting units, including historical multi-year average cash flow trends and the expected future cash flow growth rates primarily based on our estimates of future revenue, operating income, and working capital changes. Furthermore, the majority of the revenue for these reporting units is primarily dependent upon the DoD budget and spending. We closely monitor changes in these factors and their impact on the expected cash flow of the reporting units. Our DCF valuation is dependent upon several assumptions and is subject to uncertainties due to uncontrollable events, including future DoD budgets, U.S. government spending priorities for services and general economic conditions. A change in any one or a combination of the assumptions used in our DCF valuation could negatively impact the fair value, resulting in additional goodwill impairments. For the November 30, 2016 and 2015 goodwill impairment tests the weighted average long-term growth rate developed by management for purposes of our goodwill impairment analysis was 3% for both periods, and the WACC used was 9% in 2016 and 10% in 2015. The long term growth rate was evaluated considering the discrete projection period and long-term industry and economic factors. For the November 30, 2016 goodwill impairment test, the fair value for the five reporting units exceeded their carrying value by $573 million or 36%. The fair value of each of our reporting units exceeded its carrying value by at least 15% as of November 30, 2016. For November 30, 2015, the fair value of the three reporting units that did not have a goodwill impairment exceeded its carrying value by at least 20%. The amount of goodwill for each of our reporting units at December 31, 2016 is shown in the following table: Space Systems $ 288,594 Intelligence Solutions 260,129 DoD 242,243 Federal Civilian 187,582 Products 99,906 $ 1,078,454 Goodwill for the Federal civilian reporting unit decreased $15 million in 2016 which consisted of the goodwill impairment charge of $10 million as previously discussed above and $5 million that was allocated to the carrying value of assets held for sale associated with the agreement to sell IRG, as described in Note 1 under the caption titled assets held for sale. Identifiable Intangible Assets Information on our identifiable intangible assets that are subject to amortization is presented in the table below. December 31, 2016 December 31, 2015 Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in years) Customer contractual relationships 17 $ 545,229 $ 157,482 $ 387,747 $ 554,330 $ 127,264 $ 427,066 Contractual Backlog 1 21,800 21,800 — 21,800 18,850 2,950 Technology 15 7,000 856 6,144 7,000 389 6,611 Total $ 574,029 $ 180,138 $ 393,891 $ 583,130 $ 146,503 $ 436,627 In connection with the agreement to sell IRG, $9 million of the gross carrying amount of total identifiable intangible assets was allocated to the carrying value of assets held for sale in 2016 as well as the related accumulated amortization of $3 million. Our recorded amortization expense for our identifiable intangible assets is presented in the table below. Year Ended December 31, 2016 2015 2014 Amortization expense $ 36,491 $ 45,222 $ 14,856 Based on gross carrying amounts at December 31, 2016, our estimate of amortization expense for identifiable intangible assets are presented in the table below. Year Ended December 31, 2017 2018 2019 2020 2021 Amortization expense $ 32,482 $ 32,482 $ 32,482 $ 32,482 $ 32,482

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Property, Plant and Equipment	6. Property, Plant and Equipment The components of property, plant and equipment are presented in the table below. December 31, 2016 2015 Land $ 900 $ 2,200 Buildings and improvements 850 5,536 Machinery, equipment, furniture and fixtures 28,622 29,101 Leasehold improvements 43,598 22,589 Assets under construction 1,861 16,337 Gross property, plant and equipment 75,831 75,763 Accumulated depreciation and amortization (29,284 ) (31,643 ) Property, plant and equipment, net $ 46,547 $ 44,120 Our recorded depreciation expense for property, plant and equipment assets is presented in the table below. Year Ended December 31, 2016 2015 2014 Depreciation expense $ 10,306 $ 13,213 $ 6,097

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes Income (loss) before income taxes is summarized in the table below. Year Ended December 31, 2016 2015 2014 Domestic $ (9,285 ) $ (298,644 ) $ 70,267 Foreign 486 338 380 Income before income taxes $ (8,799 ) $ (298,306 ) $ 70,647 The components of our current and deferred portions of the provision for income taxes are presented in the table below. Year Ended December 31, 2016 2015 2014 Current income tax provision (benefit): Federal $ (4,030 ) $ (29,632 ) $ 22,111 State and local 107 (1,569 ) 4,462 Foreign (14 ) 727 (592 ) Subtotal (3,937 ) (30,474 ) 25,981 Deferred income tax provision (benefit): Federal 2,252 (31,830 ) 3,785 State and local (1,089 ) (5,718 ) 871 Foreign 44 (45 ) — Subtotal 1,207 (37,593 ) 4,656 Total provision (benefit) for income taxes $ (2,730 ) $ (68,067 ) $ 30,637 A reconciliation of the statutory Federal income tax rate to our effective income tax rate is presented in the table below. Year Ended December 31, 2016 2015 2014 Statutory Federal income tax rate 35.0 % 35.0 % 35.0 % State and local income taxes, net of Federal income tax benefit 6.6 1.7 4.9 Goodwill impairment (33.2 ) (18.0 ) — Non-controlling interest 18.8 0.6 (2.3 ) Non-deductible acquisition costs — (0.3 ) 3.7 Federal tax credits 2.5 0.1 — Tax audit settlements and return adjustments (3.3 ) — — Uncertain tax positions 1.3 3.9 2.6 Valuation allowance 3.9 — — Other, net (0.6 ) (0.2 ) (0.5 ) Effective income tax rate 31.0 % 22.8 % 43.4 % The significant components of our deferred tax assets and liabilities are presented in the table below. December 31, 2016 2015 Deferred tax assets: Compensation and benefits $ 26,371 $ 27,648 Unrecognized tax benefits 32,808 35,840 Fixed assets 6,627 6,504 Deferred revenue 12,917 10,469 Reserves 14,396 17,235 Pension 17,958 18,316 Net operating losses 171,969 132,511 Other 21,089 24,538 Gross deferred tax assets 304,135 273,061 Deferred tax liabilities: Goodwill and other intangible assets 49,976 15,562 Income recognition on contracts in process 7,119 15,717 Other 13,769 5,058 Gross deferred tax liabilities 70,864 36,337 Valuation allowance (988 ) (1,327 ) Net deferred tax assets $ 232,283 $ 235,397 The valuation allowance on deferred tax assets of $1 million as of December 31, 2016 and 2015 relates largely to capital loss carryforwards, charitable donations, U.S. foreign tax credits and certain state tax loss carryforwards. In addition to the above table, we have approximately $1 million of foreign income tax credits that will expire beginning in 2025. In addition to the net operating losses in the above table, we have unrecorded equity tax deductions of approximately $3 million at December 31, 2016. This amount will be credited to additional paid-in capital when the tax deduction is realized on the income tax returns. We and our subsidiaries filed income tax returns in various state and foreign jurisdictions. The Company has available at December 31, 2016, unused Federal and state operating loss carry forwards of $445 million and $412 million, respectively, that may be applied against taxable income and that expire in the years as indicated in the table below. Year of Expiration Federal State 2017-2028 $ — $ 4,974 2029-2031 109,493 85,546 2032-2034 187,519 161,356 2035-2036 147,891 160,386 $ 444,903 $ 412,262 The following table presents a reconciliation of the beginning and ending amounts of unrecognized tax benefits, excluding potential interest and penalties: Year Ended December 31, 2016 2015 2014 Balance at January 1 $ 58,360 $ 67,927 $ 67,559 Additions/reductions for tax positions related to the current year 151 4,139 890 Additions/reductions for tax positions related to prior years — (11,542 ) 51 Lapse of statute of limitations (3,237 ) (2,164 ) (573 ) Balance at December 31 $ 55,274 $ 58,360 $ 67,927 The balance of unrecognized tax benefits, exclusive of interest and penalties, was $55 million, $58 million and $68 million at December 31, 2016, 2015 and 2014, respectively. At December 31, 2016, 2015 and 2014, we had $10 million, $10 million and $12 million of interest accrued related to unrecognized tax benefits. It is expected that $10 million of unrecognized tax benefits at December 31, 2016 would affect earnings if recognized. The statutes of limitations for our U.S. Federal income tax returns remain open for the years 2012 and onward. The statute of limitations for the L-3’s U.S. Federal income tax return for the year ended December 31, 2012 remains open as of December 31, 2016. Foreign and U.S. state jurisdictions have statutes of limitations generally ranging from three to five years. As of December 31, 2016, we anticipate that uncertain tax positions will decrease by approximately $3 million over the next 12 months due to potential resolutions of uncertain tax positions involving several jurisdictions and the closing of tax statutes. The actual amount could vary significantly depending on the ultimate timing and nature of any settlements. At both December 31, 2016 and 2015, non-current income taxes payable included accrued potential interest of $10 million. With respect to the interest related items, our income tax provision included an expense (benefit) of $(1) million, $(2) million and $2 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	8. Share-Based Compensation Share-based compensation expense is summarized in the table below. Year Ended December 31, 2016 2015 2014 Share-based compensation $ 8,255 $ 9,297 $ 8,470 Income taxes (3,219 ) (3,622 ) (3,453 ) Total after income taxes $ 5,036 $ 5,675 $ 5,017 As of December 31, 2016, there was $11 million of total unrecognized compensation cost of unvested stock compensation arrangements. This cost is expected to be fully amortized over the next three years, with $6 million, $4 million, and $1 million, amortized during 2017, 2018 and 2019, respectively. These future costs include an estimated forfeiture rate. Our stock compensation costs may differ based on actual experience. The cost of stock compensation is included in the Consolidated Statements of Operations before, or in conjunction with, the vesting of options. Long Term Performance Plan Certain of our employees and directors participate in our Second Amended and Restated 2012 Long Term Performance Plan (the Amended 2012 LTPP), which includes awards originally granted under our 2012 Long Term Performance Plan and 2012 Directors Stock Incentive Plan. Stock Options: The exercise price of Engility stock options granted under the Amended 2012 LTPP may not be less than the fair market value of Engility’s common stock on the date of grant. Options expire after 10 years from the date of grant and vest ratably over a three years period on the annual anniversary of the date of grant. All unvested options are subject to forfeiture upon termination of employment (subject to customary exceptions for death or disability). All of the stock option awards issued under the Amended 2012 LTPP are non-qualified stock options for U.S. income tax regulations. The table below presents a summary of our stock option activity changes for the year ended December 31, 2016. Number of Options Weighted- Average Exercise Price Per Share Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2015 24 $ 16.83 6.2 $ 769 Granted — — Forfeited — — Exercised (24 ) 16.83 $ 152 Outstanding and exercisable at December 31, 2016 — $ — — $ — Restricted Stock Units: During the year ended December 31, 2016, we granted 506,493 RSUs to certain of our employees with a grant date fair value of $18.70 per unit, of which 56,524 RSUs cliff vest on the second anniversary of the grant date, 175,852 RSUs cliff vest on the third anniversary of the grant date and 274,117 RSUs vest over a term of three years from the grant date, 25% on the first anniversary of the grant date, 25% on the second anniversary of the grant date and 50% on the third anniversary of the grant date. Included in the total, 104,619 RSUs were granted to Ms. Dugle with a grant date fair value of $17.97 per unit, of which 50,083 RSUs cliff vest on the second anniversary of the grant date and 54,536 RSUs vest over a term of three years from the grant date. During the year ended December 31, 2016, we granted 25,704 RSUs to the independent directors with a grant date fair value of $23.34 per unit. These RSUs vest after one year from the grant date. The employee and director RSUs may be settled in cash or stock upon vesting at the sole discretion of the Compensation Committee. The table below presents a summary of our nonvested RSU awards for the year ended December 31, 2016. Number of Units Weighted- Average Grant Date Fair Value (in thousands) Nonvested balance at December 31, 2015 175 $ 34.90 Granted 532 18.92 Forfeited (59 ) 27.00 Vested (77 ) 30.97 Nonvested balance at December 31, 2016 571 $ 20.57 Director RSUs vested but not issued at December 31, 2016 37 $ 31.24 During the year ended December 31, 2016, 2015 and 2014, we granted restricted stock units with a weighted-average grant date fair value of $18.92, $32.12 and $43.21, respectively. Performance Units: During the year ended December 31, 2016, we granted 411,178 performance units at target level of 100% (with the potential for the delivery of up to 822,356 shares of our common stock at the maximum performance level) to certain of our employees with a grant date fair value of $19.33 per unit. Included in the total, 81,803 performance units were granted at target level of 100% (with the potential for the delivery of up to 163,606 shares of our common stock at the maximum performance level) to Ms. Dugle with a grant date fair value of $17.97 per unit. Performance units cliff vest after three years based on our performance at the end of a three-year period beginning January 1, 2016. The number of shares of our common stock that are ultimately vested and delivered in respect of these performance units will range from 0% to 200% of the target grant amount depending on Engility's performance, as approved by the Compensation Committee of our Board of Directors (the Compensation Committee), based on two metrics: revenue and operating cash flow. The performance units may be settled in cash or stock at the sole discretion of the Compensation Committee. The table below presents a summary of our nonvested performance share awards as of December 31, 2016. Number of Shares Weighted- Average Grant Date Fair Value (in thousands) Nonvested balance at December 31, 2015 326 $ 26.69 Granted 411 19.33 Forfeited (90 ) 29.03 Vested (130 ) 18.84 Nonvested balance at December 31, 2016 517 $ 22.86 During the year ended December 31, 2016, 2015 and 2014, we granted performance units with a weighted-average grant date fair value of $19.33, $32.29 and $56.14, respectively. Performance Retention Awards: Performance retention awards were granted to certain of our executives with a grant date fair value of $32.82 in 2015. The performance retention awards cliff vest after three years based on our performance at the end of a three-year period beginning January 1, 2015. The number of shares of our common stock that are ultimately vested and delivered in respect of these performance retention awards will range from 50% to 200% of the target grant amount depending on the Company’s performance against a metric of net debt to adjusted EBITDA, measured as of December 31, 2017. The performance retention awards may be settled in cash or stock at the sole discretion of the Compensation Committee. The table below presents a summary of our nonvested performance retention awards as of December 31, 2016. Number of Shares Weighted- Average Grant Date Fair Value (in thousands) Nonvested balance at December 31, 2015 213 $ 32.82 Granted — — Forfeited (57 ) 32.82 Vested (57 ) 32.82 Nonvested balance at December 31, 2016 99 $ 32.82 Effect of TASC Acquisition on Engility Equity Awards The TASC acquisition constituted a change of control under the grant agreements for Engility's outstanding RSUs, stock options, and performance shares. The impact on these equity grants was as follows: RSUs: Pursuant to the terms of the RSU grant agreements, 364,983 RSUs held by our employees vested. Certain executive officers waived vesting with respect to 229,166 RSUs and our independent directors waived vesting with respect to 11,790 RSUs. The TASC acquisition also triggered the issuance of shares for 43,950 vested RSUs held by the independent directors, pursuant to the terms of the grant agreements for these RSUs. Stock Options: Pursuant to the terms of the stock option grant agreements entered into with holders of outstanding stock options, the exercise price adjusted to reflect the Cash Dividend, provided, that to the extent that adjusting the exercise price by the full amount of the Cash Dividend resulted in the exercise price of the stock options falling below 25% of the fair market value of the shares underlying such stock options, such excess portion of the Cash Dividend was paid to holders of the affected stock options in cash. Performance Shares: Pursuant to the terms of the performance share agreements entered into with holders of outstanding performance shares, we fixed the number of underlying shares that are eligible to be vested and issued with respect to our outstanding grants of performance shares. For the performance shares granted in 2013, the number of eligible underlying shares was fixed at 127% of their target value based on Engility's performance against the financial metrics set forth in the grant agreements, measured as of a shortened performance period prior to the closing date of the TASC acquisition in accordance with the terms of the award agreements. For the performance shares granted in 2014, as less than half of the performance period was complete at the time of the closing of the TASC acquisition, the number of underlying shares was fixed at their target value of 100% in accordance with the terms of the award agreements. The performance shares cliff vest according to their grant agreement dates, three years from grant date. Employee Stock Purchase Plan On July 1, 2016, the shareholder-approved Employee Stock Purchase Plan (2016 ESPP) became effective. Under the 2016 ESPP, eligible employees are offered options to purchase shares of our common stock at the end of each six-month offering period at 90% of fair market value based on the closing market price for our stock on the purchase date. Eligible employees generally included all employees of Engility. The initial offering period commenced on July 1, 2016 and ended on December 31, 2016, and subsequent offering periods will begin on the first trading day in January and July of each calendar year and end on the last trading day in June and December of each calendar year. Share purchases were funded through payroll deductions of up to 10% of an employee’s eligible compensation for each payroll period, or $25 each calendar year. For the initial offering period and the year ended December 31, 2016, 32,848 shares were purchased by employees at an average price of $30.50 per share under the 2016 ESPP.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Non-Cancellable Operating Leases We lease certain facilities and equipment under agreements expiring at various dates through 2026. Certain leases contain renewal options or escalation clauses providing for increased rental payments based upon maintenance, utility and tax increases. No lease agreement imposes a restriction on our ability to pay dividends, engage in debt or equity financing transactions, or enter into further lease agreements. The following table presents future minimum base rent payments under non-cancellable operating leases with initial terms in excess of one year at December 31, 2016. Real Estate Equipment Total 2017 $ 27,559 $ 288 $ 27,847 2018 18,006 242 18,248 2019 16,329 225 16,554 2020 15,355 44 15,399 2021 14,283 — 14,283 Thereafter 36,740 — 36,740 Total minimum payments required 128,272 799 129,071 Less: Sublease rentals under non-cancellable leases (2,566 ) — (2,566 ) Net minimum payments required $ 125,706 $ 799 $ 126,505 The following table presents rent expense under non-cancellable operating leases. Year Ended December 31, 2016 2015 2014 Rent expense $ 38,945 $ 53,912 $ 23,812 Letters of Credit We enter into standby letters of credit with financial institutions covering performance and financial guarantees pursuant to contractual arrangements with certain vendors and customers. We had total outstanding letters of credit aggregating $2 million at December 31, 2016. These letters of credit may be drawn upon in the event of our nonperformance. The letters of credit reduce the borrowing capacity of our revolving line of credit dollar-for-dollar. Procurement Regulations A substantial majority of our revenue is generated from providing services and products under legally binding agreements or contracts with U.S. government and foreign government customers. U.S. government contracts are subject to extensive legal and regulatory requirements, and from time to time, agencies of the U.S. government investigate whether such contracts were and are being conducted in accordance with these requirements. Currently we are cooperating with the U.S. government on several investigations from which civil or administrative proceedings have or could result and give rise to fines, penalties, compensatory and treble damages, restitution and/or forfeitures. Currently, we do not anticipate that any of these investigations will have a material adverse effect, individually or in the aggregate, on our consolidated financial position, results of operations or cash flows. However, under U.S. government regulations, our indictment by a Federal grand jury, or an administrative finding against us as to our present responsibility to be a U.S. government contractor or subcontractor, could result in our being suspended for a period of time from eligibility for awards of new government contracts or task orders or in a loss of export privileges. A conviction, or an administrative finding against us that satisfies the requisite level of seriousness, could result in debarment from contracting with the U.S. government for a specified term. In addition, all of our U.S. government contracts: (1) are subject to audit and various pricing and cost controls, (2) include standard provisions for termination for the convenience of the U.S. government or for default, and (3) are subject to cancellation if funds for contracts become unavailable. Foreign government contracts generally include comparable provisions relating to terminations for convenience and default, as well as other procurement clauses relevant to the foreign government. Litigation Matters We are also subject to litigation, proceedings, claims or assessments and various contingent liabilities incidental to our businesses. Furthermore, in connection with certain business acquisitions, we have assumed some or all claims against, and liabilities of, such acquired businesses, including both asserted and unasserted claims and liabilities. In accordance with the accounting standard for contingencies, we record a liability when management believes that it is both probable that a liability has been incurred and we can reasonably estimate the amount of the loss. Generally, the loss is recorded at the amount we expect to resolve the liability. The estimated amounts of liabilities recorded for pending and threatened litigation are recorded in other current liabilities in the Consolidated Balance Sheets. Amounts recoverable from insurance contracts or third parties are recorded as assets when deemed probable. At December 31, 2016 and 2015, we did not record any amounts for recoveries from insurance contracts or third parties in connection with the amount of liabilities recorded for pending and threatened litigation. Legal defense costs are expensed as incurred. We believe that we have recorded adequate provisions for our litigation matters. We review these provisions quarterly and adjusts these provisions to reflect the impact of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular matter. Although we believe that we have valid defenses with respect to legal matters and investigations pending against us, the results of litigation can be difficult to predict, particularly those involving jury trials. Accordingly, our current judgment as to the likelihood of our loss (or our current estimate as to the potential range of loss, if applicable) with respect to any particular litigation matter may turn out to be wrong. Therefore, it is possible that our financial position, results of operations or cash flows could be materially adversely affected in any particular period by the unfavorable resolution of one or more of these or other contingencies.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2016
Postemployment Benefits [Abstract]
Employee Benefits	10. Employee Benefits Engility Employee Savings Plan. Under the Engility Master Savings Plan (the Engility Savings Plan), participating employees are eligible to receive Company matching or other contributions, in the form of cash effective January 1, 2015 or in the form of Engility common stock or cash in prior years, up to designated levels. For the year ended December 31, 2016, the plan provided a Company matching contribution for 100% of the first 3% of the employee contribution and 50% of the next 3% of the employee contribution. For the year ended December 31, 2015, the plan provided a Company matching contribution for 100% of the first 1.5% of the employee contribution. The Company contributions under the Engility Savings Plan were $26 million, $4 million and $0 million for the years ended December 31, 2016, 2015 and 2014, respectively. TASC Defined Contribution Plan. Effective January 1, 2016, the TASC defined contribution plan (the TASC Savings Plan) was merged into the Engility Savings Plan. Upon the closing of the TASC acquisition, we assumed TASC's defined contribution plan in which substantially all TASC employees were eligible to participate. The TASC Savings Plan provided for a Company matching contribution for 100% of the first 3% of the employee contribution and an additional 50% of the next 2% of the employee contribution. Certain employees received matching contributions at a lower percentage based on their specific matching formula. Employee and employer contributions to the plan were made each pay period and are immediately vested. The Company’s total TASC Savings Plan contributions were $14 million for the period February 26, 2015, the date of the TASC acquisition, to December 31, 2015. DRC Deferred Savings Plan. Effective January 1, 2015, the DRC deferred savings plan (the DRC Savings Plan) was merged into the Engility Savings Plan. All DRC employees were eligible to elect to defer a portion of their salary and contribute the deferred portion to the DRC Savings Plan. The DRC Savings Plan provided for a Company matching contribution for 100% of the first 2% of the employee contribution and an additional 50% of the next 4% of the employee contribution. The Company’s contributions were subject to forfeitures of any non-vested portion if termination occurred. The Company’s total DRC Savings Plan contributions were $3 million for the period January 31, 2014, the date of the DRC acquisition, to December 31, 2014. TASC Defined Benefit Plan. Upon the closing of the TASC acquisition, we assumed TASC's defined benefit plan (the TASC benefit plan) in which certain employees are eligible to participate based upon service with TASC's prior parent. This plan offers two retirement programs, a Retiree Health Reimbursement Account Plan (RHRA) and a Cash Bonus Plan, which provide a restoration of certain pension benefits that would have been forfeited as a result of years of service and final average pay being frozen by TASC's prior parent. In December of 2015, payments of $3 million were made to participants in the Cash Bonus Plan and the plan was then terminated. DRC Defined Benefit Pension Plan. DRC's Defined Benefit Pension Plan (the DRC Pension Plan) is non-contributory, covering substantially all employees of DRC who had completed a year of service prior to July 1, 2002. Membership in the DRC Pension Plan was frozen effective July 1, 2002 and participants’ calculated pension benefit was frozen effective December 31, 2006. In the fourth quarter of 2015, the Company offered certain former employees who had vested benefits in the DRC Pension Plan the option of receiving a one-time lump sum payment equal to the present value of the participant’s pension benefit (payable in cash or rolled over into a qualified retirement plan or IRA). In December 2015, payments of $17 million were made from the plan to participants accepting the lump-sum offer. The Company recorded a pre-tax non-cash settlement charge of $3 million in 2015 as a result of these transactions. Our funding policy is to contribute at least the minimum amount required by the Employee Retirement Income Security Act of 1974. Additional amounts are contributed to assure that plan assets will be adequate to provide retirement benefits. We expect to make contributions of $3 million to fund the DRC Pension Plan during 2017. Net Periodic Pension Cost DRC Pension Plan TASC Benefit Plan Year Ended December 31, 2016 Year Ended December 31, 2015 For the period from January 31, 2014 to December 31, 2014 Year Ended December 31, 2016 For the period from February 26, 2015 to December 31, 2015 Service cost $ 805 $ — $ — $ — $ — Interest cost on projected benefit obligations 2,543 3,997 3,589 468 470 Expected return on plan assets (3,813 ) (5,833 ) (5,339 ) — — Net loss amortization 292 231 — — — Settlement loss — 3,141 — — — Immediate recognition of benefit cost due to plan termination — — — — 285 Net periodic benefit income (expense) $ (173 ) $ 1,536 $ (1,750 ) $ 468 $ 755 Obligations and Funded Status DRC Pension Plan TASC Benefit Plan December 31, December 31, 2016 2015 2016 2015 Change in benefit obligation: Benefit obligation at beginning of year $ 78,665 $ 103,028 $ 18,146 $ — Service cost 805 — — — Acquired benefit obligation — — — 20,925 Interest cost 2,543 3,997 468 470 Benefits paid (4,915 ) (4,826 ) (286 ) (3,330 ) Actuarial loss (gain) 1,506 (5,459 ) (1,873 ) 81 Administrative expenses paid (872 ) (719 ) — — Settlement — (17,356 ) — — Benefit obligation at end of year 77,732 78,665 16,455 18,146 Change in plan assets: Fair value of plan assets at beginning of year 50,130 75,047 — — Actual return on plan assets 3,286 (2,433 ) — — Employer contributions 860 417 286 3,330 Benefits paid (4,915 ) (4,826 ) (286 ) (3,330 ) Administrative expenses paid (872 ) (719 ) — — Settlement — (17,356 ) — — Fair value of plan assets at end of year 48,489 50,130 — — Unfunded status $ (29,243 ) $ (28,535 ) $ (16,455 ) $ (18,146 ) Amounts recognized in the consolidated balance sheets consist of: DRC Pension Plan TASC Benefit Plan December 31, December 31, 2016 2015 2016 2015 Other current liabilities $ — $ — $ 714 $ 905 Other long-term liabilities 29,243 28,535 15,741 17,241 Net amount recognized $ 29,243 $ 28,535 $ 16,455 $ 18,146 The combined projected benefit obligation for the DRC Pension Plan and TASC Benefit Plan was $94 million and $97 million at December 31, 2016 and 2015, respectively. The reconciliation of the accumulated other comprehensive loss was as follows: DRC Pension Plan Beginning Balance Net Loss Amortization Experience Loss (Gain) Ending Balance 2016 $ 14,235 $ (292 ) $ 2,033 $ 15,976 2015 $ 14,800 $ (291 ) $ (274 ) $ 14,235 2014 $ — $ — $ 14,800 $ 14,800 TASC Benefit Plan Beginning Balance Net Loss Amortization Experience Loss (Gain) Ending Balance 2016 $ (204 ) $ — $ (1,873 ) $ (2,077 ) 2015 $ — $ — $ (204 ) $ (204 ) The amounts recognized in other comprehensive loss are reflected, net of related tax effects, as a component of accumulated other comprehensive loss as part of stockholders’ equity in the accompanying consolidated Balance Sheets. The Company expects the amortization expense related to the net actuarial loss to be immaterial in 2017. Assumptions Beginning in 2016, we refined the method used to measure interest costs for pension and postretirement benefits. Previously, the cost was determined using a single weighted-average discount rate derived from the yield curve. Under the refined method, known as the spot rate approach, we use individual spot rates along the yield curve that correspond with the timing of each benefit payment. We believe this change provides a more precise measurement of interest costs by improving the correlation between projected cash outflows and corresponding spot rates on the yield curve. Compared to the previous method, the spot rate approach decreased the interest components of our benefit costs slightly in 2016. There is no impact on the total benefit obligation. We accounted for this change prospectively as a change in accounting estimate. DRC Pension Plan The discount rate represents the estimated rate at which we could effectively settle our pension benefit obligations. In order to estimate this rate for 2016, the timing of each benefit payment was matched against the individual spot rates along the Towers Watson RATE:Link yield curve to produce a single discount rate. During 2015, future expected cash flows of the plan were matched against the Towers Watson RATE:Link yield curve to produce a single discount rate. The assumed long-term rate of return on plan assets, which is the average return expected on the funds invested or to be invested to provide future benefits to pension plan participants, is determined by an annual review of historical plan assets returns and consultation with outside investment advisors. In selecting the expected long-term rate of return on assets, the Company considered its investment return goals stated in the Pension Plan’s investment policy. The Company, with input from the Pension Plan’s professional investment managers, also considered the average rate of earnings expected on the funds invested or to be invested to provide Pension Plan benefits. This process included determining expected returns for the various asset classes that comprise the Pension Plan’s target asset allocation. TASC Benefit Plan The discount rate represents the estimated rate at which we could effectively settle our pension benefit obligations. In order to estimate this rate for 2016, the timing of each benefit payment was matched against the individual spot rates along the Towers Watson RATE:Link yield curve to produce a single discount rate. During 2015, future expected cash flows of the plan were matched against the Towers Watson RATE:Link yield curve to produce a single discount rate. The following assumptions were used to determine the benefit obligations and net periodic benefit costs: DRC Pension Plan TASC Benefit Plan December 31, December 31, 2016 2015 2016 2015 Used to determine benefit obligations: Discount rate 3.95 % 4.17 % 3.54 % 3.44 % Rate of compensation increase N/A N/A N/A N/A DRC Pension Plan TASC Benefit Plan Year Ended December 31, Year Ended December 31, 2016 2015 2014 2016 2015 Used to determine net periodic benefit costs: Discount rate 3.39 % 3.94 % (1) 4.49 % 2.85 % 3.05 % (2) Expected rate of return on assets 8.00 % 8.00 % 8.15 % N/A N/A Rate of compensation increase N/A N/A N/A N/A N/A (1) The discount rate used for the determination of the settlement in 2015 was 4.17%. (2) Represents the discounts rate for the RHRA Plan. The discount rate for the Cash Bonus Plan in 2015 was 0.95%. DRC Pension Plan Assets During 2016, the Company’s overall investment strategy for plan assets was to achieve a long-term rate of return of 8.00%, with a wide diversification of asset types, fund strategies and fund managers. The target allocation ranges for the plan assets are 45% to 65% in equity securities; 30% to 50% in fixed income securities; 0% to 20% in other types of investments and 2% to 10% in cash and cash equivalents. The risk management practices include regular evaluations of fund managers to ensure the risk assumed is commensurate with the given investment style and objectives. Prohibited investments include, but are not limited to, margin transactions. According to the plan’s investment policy, the aggregate holdings of Company common stock may not exceed 3% of the total fund. Company securities represented an immaterial percentage of trust assets as of December 31, 2016 and 2015, respectively. The Company’s investment policy includes a periodic review of the DRC Pension Plan’s investment in the various asset classes. The fair value measurement of plan assets by asset category is as follows: Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) December 31, 2016: Cash $ 301 $ 301 $ — $ — Money market funds 1,653 — 1,653 — Equity securities: Common equity securities 7,340 7,340 — — Equity mutual funds 86 86 — — Real estate investment trusts 43 43 — — Exchanged traded funds equity 17,542 17,542 — — Corporate and foreign bonds 15,101 — 15,101 — Hedge funds 6,423 — — 6,423 Total $ 48,489 $ 25,312 $ 16,754 $ 6,423 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) December 31, 2015: Cash $ 223 $ 223 $ — $ — Money market funds 3,288 3,288 — — Equity securities: Common equity securities 6,482 6,482 — — Preferred equity securities 160 160 — — Equity mutual funds 17,237 17,237 — — Real estate investment trusts 613 613 — — Corporate and foreign bonds 15,689 — 15,689 — Hedge funds 6,438 — — 6,438 Total $ 50,130 $ 28,003 $ 15,689 $ 6,438 A reconciliation of the beginning and ending balances of Level 3 assets is as follows: Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Managed Futures Hedge Funds Total Balance at January 1, 2015 $ 1,884 $ 6,442 $ 8,326 Actual returns on plan assets related to assets still held at the reporting date (3 ) (340 ) (343 ) Purchases — 336 336 Sales (1,881 ) — (1,881 ) Balance at December 31, 2015 $ — $ 6,438 $ 6,438 Actual returns on plan assets related to assets still held at the reporting date — 325 325 Purchases — 104 104 Sales — (444 ) (444 ) Balance at December 31, 2016 $ — $ 6,423 $ 6,423 The managed futures consisted of units of limited partnership interests through the allocation of assets of multiple commodity trading advisors. These commodity trading advisors engaged in speculative trading in U.S. and international markets for currencies, interest rates, stock indices, agricultural and energy products, and precious base metals. The fair value of managed futures was estimated based on the investments net asset value at the reporting period as the fair value is not readily determinable and the investment fund meets the criteria of an investment company. Redemptions could only be made monthly and require ten days prior notice to the general partner of the fund. The Company’s plan assets consist of interests in two hedge funds. One of the hedge funds is a fund of funds that combines diversified multi-strategy methods to achieve investment objectives during a three to five year investment cycle. Strategy methods may consist of conventional long-term equity and fixed income investments or derivative investments, including, total return swaps, options and forwards. The second hedge fund is a multi-strategy equity hedge fund with a focus on investment strategies that exploit market inefficiencies to produce absolute returns with low correlation to global capital markets. For both, the fair value of the hedge funds are estimated based on the investments net asset value at the reporting period as the fair value is not readily determinable and the investment fund meets the criteria of an investment company. Redemptions of the interests in both funds can be made quarterly based on the discretion of the investment company’s Board of Directors. Estimated Future Benefit Payments The following table sets forth the expected timing of benefit payments by fiscal year: DRC Pension Plan TASC Benefit Plan Total 2017 $ 4,893 $ 714 $ 5,607 2018 $ 4,938 $ 947 $ 5,885 2019 $ 4,993 $ 1,092 $ 6,085 2020 $ 5,074 $ 1,304 $ 6,378 2021 $ 5,063 $ 1,520 $ 6,583 Five subsequent fiscal years $ 25,245 $ 8,208 $ 33,453 Supplemental Executive Retirement Plan Upon the acquisition of DRC, we assumed DRC's Supplemental Executive Retirement Plan (SERP) for certain former key employees providing for annual benefits commencing on the sixth anniversary of the executive's retirement. The cost of these benefits is being charged to expense and accrued using a projected unit credit method. Expenses related to this plan were immaterial for the year ended December 31, 2016 and 2015 and for the period from the date of acquisition, January 31, 2014, to December 31, 2014. The liability related to the SERP, which is unfunded, was immaterial as of December 31, 2016 and 2015.

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	11. Debt 2016 Credit Facility On August 12, 2016, the Company and Engility Corporation entered into a credit agreement (the 2016 Credit Facility) with the lenders and issuing banks from time to time party thereto and Morgan Stanley Senior Funding, Inc., as administrative agent (Morgan Stanley). The 2016 Credit Facility provides for aggregate commitments of $1,045 million, consisting of (a) a $200 million senior secured term B1 loan facility (Term B1 Loan), (b) a $680 million senior secured term B2 loan facility (Term B2 Loan; the Term B1 Loan and the Term B2 Loan collectively are referred to as the Term Loans), and (c) a $165 million senior secured revolving credit facility (Revolver). The Revolver includes subfacilities for the issuance of letters of credit in an aggregate face amount of up to $35.0 million and a swingline commitment for swingline borrowings of up to $35.0 million at any time outstanding. The Term B1 Loan and the Term B2 Loan were fully drawn on August 12, 2016. The 2016 Credit Facility provides that Engility Corporation has the right to seek commitments to provide additional term loan facilities or additional revolving credit commitments in an aggregate principal amount up to the sum of (x) $150.0 million plus (y) an additional amount so long as, after giving pro forma effect to the incurrence of such additional borrowings, Engility Corporation’s first lien secured leverage ratio would be equal to or less than 4.00:1.00, subject to certain conditions and receipt of commitments by existing or additional lenders. The lenders under the 2016 Credit Facility are not under any obligation to provide any such additional term loan facilities or revolving credit commitments. The proceeds of the Term Loans, together with proceeds from the offering of the Notes (as defined below), were used by Engility Corporation to (i) prepay all existing indebtedness outstanding under the first lien credit agreement dated May 23, 2014, as amended, and the second lien credit agreement dated May 23, 2014, as amended, each among Engility Corporation, the lenders and issuing banks from time to time party thereto, and Barclays Bank PLC as administrative agent and collateral agent (the 2015 Credit Facilities), (ii) to pay transaction costs associated with the foregoing and (iii) for general corporate purposes. The proceeds of future borrowings under the Revolver may be used for general corporate purposes. Borrowings under the 2016 Credit Facility bear interest at a rate per annum equal to, at Engility Corporation’s option, either (a) a base rate determined by reference to the higher of (1) the interest rate announced from time to time by Morgan Stanley as its prime rate, (2) the Federal funds effective rate plus 0.5% and (3) LIBOR determined by reference to the costs of funds for U.S. dollar deposits for a one-month interest period plus 1%, subject to statutory reserves and (x) in the case of the Term B2 Loan, a floor of 1% and (y) in the case of the Term B1 Loan and Revolver, a floor of 0%, or (b) LIBOR determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing, subject to statutory reserves and (x) in the case of the Term B2 Loan, a floor of 1% and (y) in the case of the Term B1 Loan and Revolver, a floor of 0%, and in the case of either (a) or (b), plus an applicable margin. In addition to paying interest on outstanding principal under the Revolver, Engility Corporation is required to pay a commitment fee of 0.50% in respect of the unutilized commitments thereunder, payable quarterly in arrears. Engility Corporation can voluntarily reduce the unutilized portion of the commitment amount and repay outstanding loans under the 2016 Credit Facility at any time without premium or penalty, other than customary “breakage” costs with respect to LIBOR loans and a 1.00% premium if certain repricing transactions are consummated within the first six months after the borrowings of the Term Loans. The Term B1 Loan will mature on August 12, 2020 and will require scheduled quarterly payments in an amount equal to 2.50% of the original principal amount thereof, commencing December 31, 2016, with the balance paid at maturity. The Term B2 Loan will mature on August 12, 2023 and will require scheduled quarterly payments in amounts equal to 0.25% of the original principal amount thereof, commencing December 31, 2016, with the balance paid at maturity. The Revolver will mature on August 12, 2021. No amortization will be required with respect to the Revolver. In addition, the 2016 Credit Facility requires Engility Corporation to prepay outstanding Term Loans, subject to certain exceptions, with: • 50% (which percentage will be reduced to 25% if the Company’s net first lien secured leverage ratio is not greater than 3.50:1.00 and to 0% if the Company’s net first lien secured leverage ratio is not greater than 3.00:1.00) of Engility Corporation’s annual excess cash flow (as defined by the 2016 Credit Facility); • 100% of the net cash proceeds of all non-ordinary course asset sales or other non-ordinary course dispositions of property or certain casualty events, in each case subject to certain exceptions and provided that Engility Corporation may (a) reinvest within 450 days or (b) commit to reinvest those proceeds within 450 days and so reinvest such proceeds within 630 days in assets to be used in its business, or certain other permitted investments; and • 100% of the net cash proceeds of any issuance or incurrence of debt, other than proceeds from debt permitted under the 2016 Credit Facility. All obligations under the 2016 Credit Facility are unconditionally guaranteed by the Company and each of the Company’s existing and future direct and indirect material, wholly owned domestic restricted subsidiaries, subject to certain exceptions, pursuant to that certain Guarantee and Collateral Agreement, dated as of August 12, 2016, made by the Company, Engility Corporation and each of the subsidiary guarantors party thereto in favor of Morgan Stanley as collateral agent for the banks and other financial institutions or entities from time to time party to the 2016 Credit Facility (the Guarantee and Collateral Agreement). The obligations are secured by first-priority security interests in substantially all tangible and intangible assets of the Company, Engility Corporation and each subsidiary guarantor, in each case whether owned on the date of the initial borrowings or thereafter acquired. The 2016 Credit Facility requires Engility Corporation to maintain compliance with a maximum ratio of consolidated first lien secured debt to consolidated EBITDA (the consolidated first lien net leverage ratio) of 6.125 to 1.00, with incremental step downs over time, and places certain restrictions on the ability of the Company, Engility Corporation and their restricted subsidiaries to, among other things, incur debt and liens; merge, consolidate or liquidate; dispose of assets; enter into hedging arrangements; pay dividends and make other restricted payments; undertake transactions with affiliates; enter into restrictive agreements on dividends and other distributions; make negative pledges; enter into sale-leaseback transactions; make certain investments; prepay or modify the terms of certain indebtedness; and modify the terms of certain organizational agreements. We believe our most restrictive covenant is the consolidated first lien net leverage ratio requirement in the 2016 Credit Facility, which as of December 31, 2016 was 3.73:1.00. The consolidated first lien net leverage ratio is the ratio of (a) (i) funded debt secured by liens as of such date minus (ii) the unrestricted cash as of such date to (b) consolidated bank EBITDA for the period of the four fiscal quarters most recently ended. As of December 31, 2016, we were in compliance with all covenants under the 2016 Credit Facility. The 2016 Credit Facility contains customary events of default, including payment defaults, breaches of representations and warranties, covenant defaults, cross-defaults to other material indebtedness, certain events of bankruptcy and insolvency, material judgments, certain ERISA events, invalidity of loan documents and certain changes in control. Indenture and Senior Notes On August 12, 2016, the Company, Engility Corporation and certain of the Company’s wholly owned domestic subsidiaries named as guarantors (each such subsidiary and the Company individually, a Guarantor and collectively, the Guarantors) entered into an indenture with Deutsche Bank Trust Company Americas, as trustee, (the Indenture), pursuant to which Engility Corporation issued $300 million aggregate principal amount of 8.875% Senior Notes due 2024 (the Notes) and the Guarantors provided guarantees of the Notes (each individually, a Guarantee and collectively, the Guarantees). The Notes are general senior unsecured obligations of Engility Corporation, ranking equal in right of payment with Engility Corporation’s existing and future senior indebtedness and senior in right of payment of any of Engility Corporation’s future subordinated indebtedness. The Notes are effectively junior to any future or existing secured indebtedness of the Company and Engility Corporation, including indebtedness under the 2016 Credit Facility, to the extent of the value of the assets securing such indebtedness. The Notes are structurally subordinated to all existing and future indebtedness and other obligations of Engility Corporation’s subsidiaries that do not guarantee the Notes. The Guarantee of the Notes by each Guarantor is: (i) a general senior obligation of such Guarantor; (ii) equal in right of payment to all existing and future indebtedness of such Guarantor that is not subordinated in right of payment to its Guarantee of the Notes (including its guarantee of the 2016 Credit Facility); (iii) effectively subordinated to any existing and future indebtedness of such Guarantor that is secured with property or assets of such Guarantor to the extent of the value of such property and assets securing such indebtedness (including the 2016 Credit Facility); and (iv) senior in right of payment to any future indebtedness of such Guarantor that is expressly subordinated in right of payment of the Notes. Interest on the Notes is payable on March 1 and September 1 of each year, beginning on March 1, 2017, with the Notes maturing on September 1, 2024. Engility Corporation may redeem the Notes before September 1, 2019, in whole or in part, at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any, to, but not including, the redemption date plus an applicable make-whole premium. The Notes are redeemable, in whole or part, at any time on or after September 1, 2019 at the redemption prices (expressed as percentages of the principal amount thereof) set forth below, plus accrued and unpaid interest thereon, if any, to, but not including, the applicable redemption date, if redeemed during the 12-month period beginning on September 1 of each of the years indicated below: Year Percentage 2019 104.438 2020 102.219 2021 and thereafter 100.000 In addition, until September 1, 2019, Engility Corporation the Company may redeem up to 35% of the Notes with cash proceeds of certain equity offerings at a redemption price equal to 108.875% of the principal amount of the Notes plus accrued and unpaid interest, if any, to, but not including, the applicable redemption date. However, Engility Corporation may only make such redemptions if at least 60% of the aggregate principal amount of the Notes issued under the Indenture remains outstanding immediately after the occurrence of such redemption and that such redemption occurs within 120 days of the closing date of such equity offering. In the event of a change of control (as defined in the Indenture) of Engility Corporation, Engility Corporation will be required to offer to purchase the Notes at 101% of their face amount, plus accrued and unpaid interest up to, but not including, the repurchase date. The terms of the Indenture restrict the ability of Engility Corporation and certain of its subsidiaries to borrow money, create liens on assets, make distributions and pay dividends on or redeem or repurchase stock, make certain types of investments, sell stock in certain subsidiaries, enter into agreements that restrict dividends or other payments from subsidiaries, enter into transactions with affiliates, issue guarantees of debt, and sell assets or merge with other companies. These limitations are subject to a number of important exceptions and qualifications set forth in the Indenture. The Indenture provides for customary events of default which include (subject in certain cases to grace and cure periods), among others: nonpayment of principal or interest or premium, breach of covenants or other agreements in the Indenture, default for failure to pay certain other indebtedness, the failure to pay certain final judgments, and certain events of bankruptcy, insolvency or reorganization. Generally, if an event of default occurs and is continuing under the Indenture, either the trustee or the holders of at least 30% in aggregate principal amount of the Notes then outstanding may declare the principal amount plus accrued and unpaid interest on the Notes to be immediately due and payable. Registration Rights Agreement In connection with the issuance of the Notes and the Guarantees, the Company entered into a registration rights agreement dated August 12, 2016 (the Registration Rights Agreement) with Engility Corporation, the Guarantors and Morgan Stanley & Co. LLC, as the representative (the Representative) of Barclays Capital Inc., Deutsche Bank Securities Inc., J.P. Morgan Securities LLC, Regions Securities LLC, SunTrust Robison Humphrey, Inc. and Jeffries LLC (collectively, with the Representative, the Initial Purchasers). The terms of the Registration Rights Agreement require Engility Corporation and the Guarantors to use commercially reasonable efforts to (i) file a registration statement with the Securities and Exchange Commission with respect to the registered offer to exchange the Notes for new notes registered under the Securities Act of 1933, as amended, with terms substantially identical in all material respects to those of the Notes (except that the new notes will not contain terms with respect to transfer restrictions or provide for payment of additional interest) and consummate such exchange on or before the 365th day after August 12, 2016 and (ii) in certain circumstances, file a shelf registration statement with respect to resales of the Notes. The Registration Rights Agreement provides that if a “Registration Default” (as defined in the Registration Rights Agreement) occurs and is continuing, then additional interest shall accrue on the principal amount of the Notes that are “Transfer Restricted Securities” (as defined in the Registration Rights Agreement) at a rate of 0.25% per annum (which rate will be increased by an additional 0.25% per annum for each subsequent 90-day period that such additional interest continues to accrue, provided that the rate at which such additional interest accrues may in no event exceed 1.0%). 2015 Credit Facilities On August 12, 2016, in connection with the effectiveness of the 2016 Credit Facility, as described above, the Company terminated its 2015 Credit Facilities. The 2015 Credit Facilities consisted of: (i) an $830 million senior secured first lien term loan facility, (ii) a $115 million senior secured revolving credit facility and (iii) a $400 million senior secured second lien term loan facility. In connection with the acquisition of TASC, which included the payment of the Cash Dividend and the repayment of outstanding debt under the 2013 Credit Facility (as defined below), we borrowed $585 million under a promissory note issued by our wholly-owned subsidiary Engility LLC (f/k/a Engility Corporation) and guaranteed by Predecessor Engility (as defined below) and certain other Predecessor Engility subsidiaries (the Engility Bridge Loan). In addition, we guaranteed the debt of TASC comprised of the First Lien Credit Agreement and the Second Lien Credit Agreement, consisting of (a)(i) a $395 million senior secured first lien term loan facility (the Original First Lien Term Facility), (ii) a $50 million senior secured revolving credit facility and (iii) a $250 million senior secured second lien term loan facility (the Original Second Lien Term Facility) (the existing facilities in clauses (a)(i) through (a)(iii), collectively, the TASC Existing Credit Facilities) and (b)(i) a new $435 million senior secured first lien term loan facility (the Incremental First Lien Term Facility), (ii) additional senior secured first lien revolving credit capacity in an aggregate principal amount of $65 million and (iii) a new $150 million senior secured second lien term loan facility (the Incremental Second Lien Term Facility) (the incremental facilities in clauses (b)(i) through (iii), collectively, the TASC Incremental Facilities and along with the TASC Existing Credit Facilities, the 2015 Credit Facility), in each case with Barclays Bank PLC as administrative agent. All borrowings under the 2015 Credit Facility pursuant to the First Lien Credit Agreement bore interest at a variable rate per annum equal to an applicable margin, plus, at our option (other than for swing line loans), either (1) a base rate determined by reference to the highest of (a) the prime rate of Barclays Bank PLC, (b) the Federal funds effective rate plus 0.50% and (c) a LIBOR rate determined by reference to the cost of funds for U.S. dollar deposits for the interest period of one month, plus 1.00% or (2) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing, provided that for the Original First Lien Term Facility and Incremental First Lien Term Facility, the LIBOR rate shall not be less than 1.00%. All swing line loans bore interest at a variable rate per annum equal to an applicable margin, plus a base rate determined as described in the immediately preceding sentence. The applicable LIBOR margin and the applicable base rate margin for borrowings under the First Lien Credit Agreement were 6.00% and 5.00%, respectively. All borrowings under the 2015 Credit Facility pursuant to the Second Lien Credit Agreement bore interest at a rate per annum equal to 12.00%. 2013 Credit Facility On August 9, 2013, we, through our wholly owned subsidiary, Engility Corporation, entered into a credit facility among the Company, Engility Corporation, Bank of America, N.A. (as administrative agent, swing line lender and letter of credit issuer) and each of the several lenders from time to time party thereto (the 2013 Credit Facility). The 2013 Credit Facility, which was replaced by the 2015 Credit Facility, provided for (1) a $200 million term loan facility maturing on August 9, 2018, and (2) a $250 million revolving credit facility, with a $50 million letter of credit sublimit and a $25 million swing line loan sublimit. The 2013 Credit Facility also contained an accordion feature that permitted us to arrange with the lenders for the provision of up to $150 million in additional commitments. On January 31, 2014, we acquired DRC for total consideration of approximately $207 million (including the retirement of approximately $86 million of debt of DRC) as described in Note 3. We financed the DRC acquisition in part by drawing down on the $150 million accordion under the 2013 Credit Facility, utilizing an incremental term loan of $75 million and an incremental revolving facility of $75 million. We amended the 2013 Credit Facility on this same date to (i) provide for the incremental term loan and incremental revolving credit facility and (ii) replenish the $150 million availability under the accordion. Pursuant to the amendment, the incremental term loan facility was set to mature on August 9, 2018 and the incremental revolving credit facility was set to terminate on August 9, 2018. The amendment did not change the interest rate under the 2013 Credit Facility. All borrowings under the 2013 Credit Facility bore interest at a variable rate per annum equal to an applicable margin, plus, at our option (other than for swing line loans), either (1) a base rate determined by reference to the highest of (a) the prime rate of Bank of America, N.A., (b) the Federal funds effective rate plus 0.50% and (c) a LIBOR rate determined by reference to the cost of funds for U.S. dollar deposits for the interest period of one month plus 1.00% or (2) a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing. All swing line loans bore interest at a variable rate per annum equal to an applicable margin, plus a base rate determined as described in the immediately preceding sentence. The applicable margins for the borrowings under the 2013 Credit Facility depended on the consolidated leverage ratio of Engility Holdings, Inc., Engility Corporation and its subsidiaries. The applicable LIBOR margin varied between 2.25% and 3.25%, and the applicable base rate margin varied between 1.25% and 2.25%. Debt Summary The composition of our debt at December 31, 2016 and 2015 was as follows: December 31, 2016 2015 Term Loans $ 823,300 $ 1,159,725 Notes 300,000 — Other 461 590 Total debt 1,123,761 1,160,315 Less: current portion of long-term debt (26,947 ) (8,447 ) Less: unamortized original issue discount costs and financing fees (56,821 ) (57,839 ) Long-term debt $ 1,039,993 $ 1,094,029 Our availability under the Revolver of the 2016 Credit Facility was $163 million as of December 31, 2016, with $2 million outstanding under letters of credit. During the year ended December 31, 2016, we repaid a total of $91 million of debt under the 2016 and 2015 Credit Facilities. In addition to regular mandatory payments of $11 million made in 2016, under the 2015 Credit Facility $10 million of second lien term loan debt was purchased in the first quarter of 2016 and $20 million of term loan debt was prepaid during the second quarter of 2016. Under the 2016 Credit Facility, we prepaid $50 million of Term B2 Loan debt in the second half of 2016. During the year ended December 31, 2016, in connection with the termination of the 2015 Credit Facilities, the Company incurred a $10 million early termination penalty under the Second Lien Credit Agreement. The Company also expensed $5 million of deferred debt issuance costs associated with the 2015 Credit Facilities in 2016. In addition, the Company expensed approximately $11 million of debt issuances costs related to the 2016 Credit Facility and Notes that did not qualify for deferral. During the year ended December 31, 2015, in connection with the TASC Incremental Facilities, the Company expensed $5 million of deferred debt issuance costs associated with the 2013 Credit Facility. Furthermore, the Company expensed debt issuance costs of approximately $1 million that did not qualify for deferral. These amounts are reflected in interest expense, net in the Consolidated Statements of Operations. During the year ended December 31, 2016, we had a weighted average outstanding loan balance of $1,147 million, which accrued interest at a weighted average borrowing rate of approximately 8.07%. Our weighted average outstanding loan balance for the year ended December 31, 2015 was $1,077 million, which accrued interest at a weighted average borrowing rate of approximately 8.22%. Our weighted average outstanding loan balance for the year ended December 31, 2014 was $342 million, which accrued interest at a weighted average borrowing rate of approximately 2.92%. The following table presents our minimum debt payments under the 2016 Credit Facility and the Indenture. 2017 $ 26,800 2018 26,800 2019 26,800 2020 141,800 2021 6,800 Thereafter 894,300 Total minimum payments required $ 1,123,300

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	12. Fair Value Measurements Derivative Instruments In connection with the refinancing of the 2015 Credit Facility, the Company terminated its interest rate swap agreements related to the 2015 Credit Facility which resulted in a $2 million termination charge and a loss of approximately $1 million in 2016. The Company’s interest rate swap liabilities were measured at fair value on a recurring basis and were aggregated by the level in the fair value hierarchy within which those measurements fall. All instruments were classified as Level 2 and there were no transfers of financial instruments between the three levels of fair value hierarchy during the periods the interest rate swap agreements were in effect. At December 31, 2015, the interest rate swap liability was included in other current liabilities in the accompanying consolidated balance sheets. The derivative instruments were comprised of a combined notional amount of $200 million effective December 31, 2015 which would have expired December 31, 2016. The notional amount represents the gross contract notional amount of the derivatives outstanding. The other terms of these instruments were as follows: Contract received: Floating interest rate LIBOR (subject to minimum of 1.25%) Contract paid: Fixed interest rates 3.09% - 3.18% Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents our assets and liabilities that are measured at fair value on a recurring basis: Fair December 31, 2016 December 31, 2015 Interest rate swap liability Level 2 $ — $ 3,590

Restructuring and Integration C

Restructuring and Integration Costs	12 Months Ended
	Dec. 31, 2016
Restructuring And Related Activities [Abstract]
Restructuring and Integration Costs	13. Restructuring and Integration Costs 2016 Costs During the year ended December 31, 2016, we incurred $12 million in restructuring costs, including severance which will be paid out by the first quarter of 2017 and other costs to include lease termination fees which were paid out by the end of 2016. 2015 Costs During the year ended December 31, 2015 in conjunction with the integration of TASC, we incurred $21 million in restructuring costs, including costs related to workforce reduction which were paid out during 2016, and other costs to include contract and lease termination fees which will be paid out through fiscal year 2017. 2014 Costs During the year ended December 31, 2014 in conjunction with the integration of DRC, and our move to a customer focused model, we incurred $1 million in restructuring costs, including costs related to workforce reduction. Summary The activity and balance of the liability accounts for the years ended December 31, 2016, 2015 and 2014 are as follows: Severance and Related Costs Other Restructuring Costs Total Balance as of January 1, 2014 $ 337 $ 7,533 $ 7,870 Additions 1,134 — 1,134 Cash payments (1,103 ) (1,497 ) (2,600 ) Balance as of December 31, 2014 $ 368 $ 6,036 $ 6,404 Additions 14,614 6,476 21,090 Cash payments (10,976 ) (3,041 ) (14,017 ) Balance as of December 31, 2015 $ 4,006 $ 9,471 $ 13,477 Additions 9,357 2,186 11,543 Cash payments (12,059 ) (6,704 ) (18,763 ) Other adjustments — (2,429 ) (2,429 ) Balance as of December 31, 2016 $ 1,304 $ 2,524 $ 3,828 Restructuring and integration costs are contained within the selling, general and administrative expense line in the accompanying consolidated statement of operations. Amounts recognized in the consolidated balance sheets as of December 31, 2016 and 2015 consist of: Severance and Related Costs Other Restructuring Costs Total December 31, 2015 Other current liabilities $ 4,006 $ 5,392 $ 9,398 Other liabilities — 4,079 4,079 Amount recognized $ 4,006 $ 9,471 $ 13,477 December 31, 2016 Current liabilities $ 1,304 $ 2,524 $ 3,828 Amount recognized $ 1,304 $ 2,524 $ 3,828

Separate Financial Information

Separate Financial Information of Subsidiary Guarantor of Indebtedness	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Separate Financial Information of Subsidiary Guarantor of Indebtedness	14. Separate Financial Information of Subsidiary Guarantor of Indebtedness The following tables present supplemental condensed consolidating financial statements of (a) Engility Holdings, Inc., as parent company guarantor, (b) Engility Corporation, as subsidiary issuer of the Notes; (c) on a combined basis, the subsidiary guarantors of the Notes; and (d) on a combined basis, the subsidiaries that are not guarantors of the Notes. Separate financial statements of the subsidiary guarantors are not presented because the parent company owns 100% of the outstanding voting stock of each of the subsidiary guarantors and the guarantee by each subsidiary guarantor is joint and several and full and unconditional, except for certain customary limitations. These customary limitations, which are described in detail in the Indenture, include (i) the sale, exchange or transfer of a guarantor, (ii) the guarantor ceasing to guarantee the 2016 Credit Facility, (iii) the designation of a guarantor as a unrestricted subsidiary (iv) exercising the legal defeasance, covenant defeasance or discharge of the Indenture, and (v) the merger or consolidation of a guarantor with the issuer or another guarantor of the Indenture. As a result and in accordance with Rule 3-10(d) of Regulation S-X under the Securities Exchange Act of 1934, as amended, the Company includes the following tables in these notes to the condensed consolidated financial statements: SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF DECEMBER 31, 2016 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 31,124 $ 385 $ 16,727 $ — $ 48,236 Receivables, net — 280,709 34,655 18,884 — 334,248 Intercompany receivables — 83,739 — 758 (84,497 ) — Prepaid income taxes — 5,211 — 219 — 5,430 Assets held for sale, current — 2,332 17,910 — — 20,242 Other current assets — 22,226 506 2,242 — 24,974 Total current assets — 425,341 53,456 38,830 (84,497 ) 433,130 Property, plant and equipment, net — 40,071 6,345 131 — 46,547 Goodwill — 1,020,027 58,427 — — 1,078,454 Identifiable intangible assets, net — 359,465 34,426 — — 393,891 Deferred tax assets — 213,296 18,987 — — 232,283 Assets held for sale — — 11,962 — — 11,962 Investment in subsidiaries 704,805 89,543 29,248 — (823,596 ) — Other assets — 2,292 — — — 2,292 Total assets $ 704,805 $ 2,150,035 $ 212,851 $ 38,961 $ (908,093 ) $ 2,198,559 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 26,947 $ — $ — $ — $ 26,947 Accounts payable, trade — 43,848 37 58 — 43,943 Intercompany payable — 758 83,739 — (84,497 ) — Accrued employment costs — 87,199 4,530 7,131 — 98,860 Accrued expenses — 76,520 — 350 — 76,870 Advance payments and billings in excess of costs incurred — 33,259 — — — 33,259 Deferred income taxes, current and income tax liabilities — — — 230 (21 ) 209 Liabilities held for sale, current — — 4,341 — — 4,341 Other current liabilities — 34,398 47 1,944 21 36,410 Total current liabilities — 302,929 92,694 9,713 (84,497 ) 320,839 Long-term debt — 1,039,993 — — — 1,039,993 Income tax liabilities — 64,852 — — — 64,852 Liabilities held for sale — — 1,084 — — 1,084 Other liabilities — 37,456 29,530 — — 66,986 Total liabilities $ — $ 1,445,230 $ 123,308 $ 9,713 $ (84,497 ) $ 1,493,754 Shareholders' equity 704,805 704,805 89,543 29,248 (823,596 ) 704,805 Total liabilities and equity $ 704,805 $ 2,150,035 $ 212,851 $ 38,961 $ (908,093 ) $ 2,198,559 SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF DECEMBER 31, 2015 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 18,313 $ 29 $ 11,680 $ — $ 30,022 Receivables, net — 314,917 44,665 22,178 — 381,760 Intercompany receivables — 4,983 — — (4,983 ) — Prepaid income taxes — 4,811 — 192 — 5,003 Other current assets — 22,731 3 1,921 — 24,655 Total current assets — 365,755 44,697 35,971 (4,983 ) 441,440 Property, plant and equipment, net — 37,415 6,344 361 — 44,120 Goodwill — 1,034,751 58,427 — — 1,093,178 Identifiable intangible assets, net — 399,570 37,057 — — 436,627 Deferred tax assets — 210,727 24,670 — — 235,397 Investment in subsidiaries 706,133 141,630 23,401 — (871,164 ) — Other assets — 2,229 982 — — 3,211 Total assets $ 706,133 $ 2,192,077 $ 195,578 $ 36,332 $ (876,147 ) $ 2,253,973 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 8,447 $ — $ — $ — $ 8,447 Accounts payable, trade — 50,468 3,628 249 — 54,345 Intercompany payable — — 2,030 2,953 (4,983 ) — Accrued employment costs — 64,463 9,789 7,459 — 81,711 Accrued expenses — 76,606 5,809 350 — 82,765 Advance payments and billings in excess of costs incurred — 48,876 329 — — 49,205 Deferred income taxes, current and income tax liabilities — 447 — 248 — 695 Other current liabilities — 34,590 31 1,672 — 36,293 Total current liabilities — 283,897 21,616 12,931 (4,983 ) 313,461 Long-term debt — 1,094,029 — — — 1,094,029 Income tax liabilities — 68,000 — — — 68,000 Other liabilities — 40,018 32,332 — — 72,350 Total liabilities $ — $ 1,485,944 $ 53,948 $ 12,931 $ (4,983 ) $ 1,547,840 Shareholders' equity 706,133 706,133 141,630 23,401 (871,164 ) 706,133 Total liabilities and equity $ 706,133 $ 2,192,077 $ 195,578 $ 36,332 $ (876,147 ) $ 2,253,973 SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE YEAR ENDED DECEMBER 31, 2016 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,730,876 $ 191,381 $ 154,166 $ — $ 2,076,423 Costs and expenses Cost of revenue — 1,423,013 213,650 141,181 — 1,777,844 Selling, general and administrative expenses — 132,476 30,703 3,059 — 166,238 Goodwill impairment — 9,875 — — — 9,875 Total costs and expenses — 1,565,364 244,353 144,240 — 1,953,957 Operating income (loss) — 165,512 (52,972 ) 9,926 — 122,466 Interest expense, net — 131,185 — — — 131,185 Other income (expenses), net — 135 (1 ) (214 ) — (80 ) Income in equity investments in subsidiaries (10,807 ) (52,259 ) 4,974 — 58,092 — Income (loss) before income taxes (10,807 ) (17,797 ) (47,999 ) 9,712 58,092 (8,799 ) Benefit for income taxes — (6,990 ) 4,260 — — (2,730 ) Net income (loss) (10,807 ) (10,807 ) (52,259 ) 9,712 58,092 (6,069 ) Less: Net income attributable to non-controlling interest — — — 4,738 — 4,738 Net income (loss) attributable to Engility $ (10,807 ) $ (10,807 ) $ (52,259 ) $ 4,974 $ 58,092 $ (10,807 ) Net income (loss) $ (10,807 ) $ (10,807 ) $ (52,259 ) $ 9,712 $ 58,092 $ (6,069 ) Other comprehensive income — 2,191 173 — — 2,364 Comprehensive income (loss) (10,807 ) (8,616 ) (52,086 ) 9,712 58,092 (3,705 ) Less: Net income attributable to non-controlling interest — — — 4,738 — 4,738 Comprehensive income (loss) attributable to Engility $ (10,807 ) $ (8,616 ) $ (52,086 ) $ 4,974 $ 58,092 $ (8,443 ) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE LOSS FOR THE YEAR ENDED DECEMBER 31, 2015 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,622,029 $ 325,926 $ 156,704 $ (19,036 ) $ 2,085,623 Costs and expenses Cost of revenue — 1,384,997 270,790 142,958 (19,036 ) 1,779,709 Selling, general and administrative expenses — 163,019 36,540 3,703 — 203,262 Goodwill impairment — 183,577 108,523 — — 292,100 Total costs and expenses — 1,731,593 415,853 146,661 (19,036 ) 2,275,071 Operating income (loss) — (109,564 ) (89,927 ) 10,043 — (189,448 ) Interest expense, net — 110,148 — (5 ) — 110,143 Other income (expenses), net — 1,289 (4 ) — — 1,285 Income in equity investments in subsidiaries (235,352 ) (60,844 ) 4,935 — 291,261 — Income (loss) before income taxes (235,352 ) (279,267 ) (84,996 ) 10,048 291,261 (298,306 ) Benefit for income taxes — (43,915 ) (24,152 ) — — (68,067 ) Net income (loss) (235,352 ) (235,352 ) (60,844 ) 10,048 291,261 (230,239 ) Less: Net income attributable to non-controlling interest — — — 5,113 — 5,113 Net income (loss) attributable to Engility $ (235,352 ) $ (235,352 ) $ (60,844 ) $ 4,935 $ 291,261 $ (235,352 ) Net income (loss) $ (235,352 ) $ (235,352 ) $ (60,844 ) $ 10,048 $ 291,261 $ (230,239 ) Other comprehensive income — 1,428 361 — — 1,789 Comprehensive income (loss) (235,352 ) (233,924 ) (60,483 ) 10,048 291,261 (228,450 ) Less: Net income attributable to non-controlling interest — — — 5,113 — 5,113 Comprehensive income (loss) attributable to Engility $ (235,352 ) $ (233,924 ) $ (60,483 ) $ 4,935 $ 291,261 $ (233,563 ) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME FOR THE YEAR ENDED DECEMBER 31, 2014 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ — $ 1,228,538 $ 148,243 $ (9,690 ) $ 1,367,091 Costs and expenses Cost of revenue — — 1,040,552 138,419 (9,690 ) 1,169,281 Selling, general and administrative expenses — — 113,216 1,674 — 114,890 Total costs and expenses — — 1,153,768 140,093 (9,690 ) 1,284,171 Operating income — — 74,770 8,150 — 82,920 Interest expense, net — — 12,803 (4 ) — 12,799 Other income, net — — 526 — — 526 Income in equity investments in subsidiaries 35,423 — 3,567 — (38,990 ) — Income before income taxes 35,423 — 66,060 8,154 (38,990 ) 70,647 Provision for income taxes — — 30,637 — — 30,637 Net income 35,423 — 35,423 8,154 (38,990 ) 40,010 Less: Net income attributable to non-controlling interest — — — 4,587 — 4,587 Net income attributable to Engility $ 35,423 $ — $ 35,423 $ 3,567 $ (38,990 ) $ 35,423 Net income $ 35,423 $ — $ 35,423 $ 8,154 $ (38,990 ) $ 40,010 Other comprehensive loss — — (9,018 ) — — (9,018 ) Comprehensive income 35,423 — 26,405 8,154 (38,990 ) 30,992 Less: Net income attributable to non-controlling interest — — — 4,587 — 4,587 Comprehensive income attributable to Engility $ 35,423 $ — $ 26,405 $ 3,567 $ (38,990 ) $ 26,405 SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE YEAR ENDED DECEMBER 31, 2016 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ 163,136 $ (81,354 ) $ 12,623 $ — $ 94,405 Investing activities: Acquisitions, net of cash acquired — — — — — — Capital expenditures — (21,446 ) — — — (21,446 ) Net cash used in investing activities — (21,446 ) — — — (21,446 ) Financing activities: Gross borrowings from issuance of long-term debt — 1,180,000 — — — 1,180,000 Repayment of long-term debt — (1,215,754 ) — — — (1,215,754 ) Gross borrowings from revolving credit facility — 137,000 — — — 137,000 Repayments of revolving credit facility — (137,000 ) — — — (137,000 ) Debt issuance costs — (9,988 ) — — — (9,988 ) Equity issuance costs — — — — — — Proceeds from share-based payment arrangements 214 — — — — 214 Payment of employee withholding taxes on share- based compensation (1,779 ) — — — — (1,779 ) Excess tax deduction on share-based compensation — — — — — — Dividends paid (1,709 ) — — — — (1,709 ) Distributions to non-controlling interest member — — — (3,865 ) — (3,865 ) Due (to) from subsidiaries 3,274 (81,273 ) 81,710 (3,711 ) — — Net cash used in financing activities — (127,015 ) 81,710 (7,576 ) — (52,881 ) Change in cash from assets held for sale — (1,864 ) — — — (1,864 ) Net change in cash and cash equivalents — 12,811 356 5,047 — 18,214 Cash and cash equivalents, beginning of period — 18,313 29 11,680 — 30,022 Cash and cash equivalents, end of period $ — $ 31,124 $ 385 $ 16,727 $ — $ 48,236 SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE YEAR ENDED DECEMBER 31, 2015 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ 45,633 $ (10,754 ) $ 13,539 $ — $ 48,418 Investing activities: Acquisitions, net of cash acquired — 25,478 — — — 25,478 Capital expenditures — (19,610 ) — — — (19,610 ) Net cash provided by investing activities — 5,868 — — — 5,868 Financing activities: Gross borrowings from issuance of long-term debt — 585,000 — — — 585,000 Repayment of long-term debt — (403,674 ) — — — (403,674 ) Gross borrowings from revolving credit facility — 157,000 — — — 157,000 Repayments of revolving credit facility — (115,000 ) — — — (115,000 ) Debt issuance costs — (42,425 ) — — — (42,425 ) Equity issuance costs (2,590 ) — — — — (2,590 ) Proceeds from share-based payment arrangements 279 — — — — 279 Payment of employee withholding taxes on share- based compensation (8,021 ) — — — — (8,021 ) Excess tax deduction on share-based compensation 5,530 — — — — 5,530 Dividends paid (204,304 ) — — — — (204,304 ) Distributions to non-controlling interest member — — — (3,182 ) — (3,182 ) Due (to) from subsidiaries 209,106 (214,089 ) 7,656 (2,673 ) — Net cash used in financing activities — (33,188 ) 7,656 (5,855 ) — (31,387 ) Net change in cash and cash equivalents — 18,313 (3,098 ) 7,684 — 22,899 Cash and cash equivalents, beginning of period — — 3,127 3,996 — 7,123 Cash and cash equivalents, end of period $ — $ 18,313 $ 29 $ 11,680 $ — $ 30,022 SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE YEAR ENDED DECEMBER 31, 2014 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ — $ 104,849 $ (2,490 ) $ — $ 102,359 Investing activities: Acquisitions, net of cash acquired — — (207,250 ) — — (207,250 ) Capital expenditures — — (5,436 ) — — (5,436 ) Net cash used in investing activities — — (212,686 ) — — (212,686 ) Financing activities: Gross borrowings from issuance of long-term debt — — 75,000 — — 75,000 Repayment of long-term debt — — (13,750 ) — — (13,750 ) Gross borrowings from revolving credit facility — — 482,500 — — 482,500 Repayments of revolving credit facility — — (448,000 ) — — (448,000 ) Debt issuance costs — — (1,131 ) — — (1,131 ) Equity issuance costs — — — — — — Proceeds from share-based payment arrangements 1,479 — — — — 1,479 Payment of employee withholding taxes on share- based compensation (2,371 ) — — — — (2,371 ) Excess tax deduction on share-based compensation 1,707 — — — — 1,707 Dividends paid — — — — — — Distributions to non-controlling interest member — — — (6,987 ) — (6,987 ) Due (to) from subsidiaries (815 ) — (950 ) 1,765 — — Net cash provided by financing activities — — 93,669 (5,222 ) — 88,447 Net change in cash and cash equivalents — — (14,168 ) (7,712 ) — (21,880 ) Cash and cash equivalents, beginning of period — — 17,295 11,708 — 29,003 Cash and cash equivalents, end of period $ — $ — $ 3,127 $ 3,996 $ — $ 7,123

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Events On January 6, 2017, the Company completed the sale of its international development services business, IRG, a wholly-owned subsidiary of the Company for a purchase price of $24 million in cash. The sale was the result of the Company’s strategic review of its business and determination that the USAID portion of the Company’s international business no longer closely aligned with the Company’s future strategic direction. The Company received the proceeds from this sale, less an indemnity escrow of approximately $2 million, in the first quarter of 2017, which was used to pay down existing debt. The Company is expected to receive the indemnity escrow on or about the second anniversary of the sale assuming no claims are made against the escrow funds. On February 13, 2017 the Company, and Engility Corporation entered into Amendment No. 1 (the “Amendment”) to the Credit Agreement, dated as of August 12, 2016, among the Borrower, the Company, the several lenders from time to time parties thereto and Morgan Stanley, as administrative agent and collateral agent. The parties entered into the Amendment in order to reduce the interest rate spread applicable to (i) the Borrower’s senior secured term B1 loan facility in the original principal amount of $200 million (“Existing Term B1 Loans”) from 3.25% to 2.25%, in the case of alternate base rate loans, and from 4.25% to 3.25%, in the case of Eurocurrency loans, and (ii) the Borrower’s senior secured term B2 loan facility in the original principal amount of $680 million (“Existing Term B2 Loans”) from 3.75% to 2.75%, in the case of alternate base rate loans, and from 4.75% to 3.75%, in the case of Eurocurrency loans. The Amendment was accomplished by (i) the Borrower obtaining new term B1 loan commitments (“New Term B1 Loans”) to reprice the Existing Term B1 Loans and Morgan Stanley making additional New Term B1 Loans to the Borrower in a principal amount equal to $195.0 million minus the principal amount of any Existing Term B1 Loans outstanding on the Amendment Effective Date that were converted into New Term B1 Loans on the Amendment Effective Date, and (ii) the Borrower obtaining new term B2 loan commitments (“New Term B2 Loans”) to reprice the Existing Term B2 Loans and Morgan Stanley making additional New Term B2 Loans to the Borrower in a principal amount equal to $608.0 million minus the principal amount of any Existing Term B2 Loans outstanding on the Amendment Effective Date that were converted into New Term B2 Loans on the Amendment Effective Date. The proceeds of the New Term B1 Loans and New Term B2 Loans, respectively, will be applied to repay in full the Existing Term B1 Loans and Existing Term B2 Loans, respectively, outstanding as of the Amendment Effective Date. The transaction is expected to lower the Company’s fiscal year 2017 interest expense by approximately $5 million after fees and expenses.

Basis of Presentation (Policies

Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	Description of Business: Engility Holdings, Inc. (Engility) has provided mission critical services to the U.S. government for over six decades. Engility has a diversified portfolio that serves the U.S. Department of Defense (DoD), U.S. Department of Justice (DoJ), U.S. Department of State (DoS), Federal Aviation Administration (FAA), Department of Homeland Security (DHS), and space-related and intelligence community agencies, including the National Geospatial-Intelligence Agency (NGA), Defense Intelligence Agency (DIA), the National Reconnaissance Office (NRO), and National Aeronautical and Space Administration (NASA). As used herein, the terms “Engility,” the “Company,” “we,” “us” or “our” refers to (i) Engility and its subsidiaries, for all periods prior to the closing of the TASC, Inc. (TASC) acquisition, and (ii) New Engility and its subsidiaries, for all periods following the TASC acquisition. The TASC acquisition was effected through a new holding company named New East Holdings, Inc. (New Engility). As a result of the business combination, New Engility succeeded to and continues to operate, directly or indirectly, the existing business of Engility and, indirectly, acquired the existing business of TASC. As of December 31, 2016, we employed approximately 9,100 individuals globally and operated in 49 countries. We are led by a seasoned executive team, which is composed of industry, U.S. military and government veterans. We offer a broad range of services, including specialized technical consulting, program and business support, engineering and technology lifecycle support, information technology modernization and sustainment, supply chain services and logistics management and training and education to the U.S. government worldwide. Engility has no operations other than owning 100% of the capital stock of Engility Corporation (formerly TASC, Inc.), a Massachusetts corporation (Engility Corporation), and the consolidated financial statements of Engility and its consolidated subsidiaries are identical in all respects to the consolidated financial statements of Engility Corporation and its consolidated subsidiaries. On July 17, 2012, L-3 Communications Holdings, Inc. completed the spin-off of Engility Holdings, Inc. from L-3. We retained the systems engineering and technical assistance, training and operational support services businesses that were previously part of L-3’s Government Services segment. Unless the context indicates otherwise, (i) references to Engility, the Company, we, us or our refer to Engility Holdings, Inc. and its subsidiaries and (ii) references to L-3 refer to L-3 Communications Holdings and its subsidiaries.
Principles of Consolidation and Combination and Basis of Presentation	Principles of Consolidation and Combination and Basis of Presentation: The Consolidated Financial Statements are prepared in conformity with accounting principles generally accepted in the United States of America (U.S. GAAP) and reflect the financial position, results of operations and cash flows of Engility as a separate standalone entity. The Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. On January 31, 2014 and February 26, 2015, we completed the acquisitions of Dynamics Research Corporation (DRC) and TASC, respectively, which are more fully described in Note 3. These transactions were recorded using the purchase method of accounting; accordingly, DRC's and TASC's financial results are included in the Consolidated Financial Statements for the periods subsequent to the acquisition.
Non-controlling Interest	Non-controlling Interest: Engility holds a 50.1% majority interest in Forfeiture Support Associates J.V. (FSA). The results of operations of FSA are included in Engility’s Consolidated Statements of Operations. The non-controlling interest reported on the Consolidated Balance Sheets represents the portion of FSA’s equity that is attributable to the non-controlling interest.
Accounting Estimates	Accounting Estimates: The preparation of financial statements in conformity with GAAP requires management to make estimates using assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. The most significant of these estimates include the recoverability, useful lives and valuation of identifiable intangible assets and goodwill, income taxes and contingencies. Actual results experienced by the Company may differ materially from management's estimates.
Out-of-period adjustments	Out-of-period adjustments: During 2016, the Company recorded out-of-period adjustments that decreased pre-tax income by $ 2 million to correct errors related to the year ended December 31, 2015. The adjustments were not material to 2016 or any previously issued financial statements.
Revenue Recognition	Revenue Recognition: Substantially all of the Company’s revenue is derived from services provided to the U.S. government and its agencies, primarily by the Company’s consulting staff and, to a lesser extent, subcontractors. The Company generates its revenue from the following types of contractual arrangements: cost-reimbursable-plus-fee contracts, time-and-materials contracts, and fixed-price contracts. Revenue on cost-reimbursable-plus-fee contracts is recognized as services are performed, generally based on allowable costs plus any recognizable earned fee. The Company considers fixed fees under cost-reimbursable-plus-fee contracts to be earned in proportion to the allowable costs incurred in performance of the contract. For cost-reimbursable-plus-fee contracts that include performance-based fee incentives, which are principally award fee arrangements, revenue and profit on award fees are recognized as work on the contracts is performed. We have significant history with the client for the majority of these contracts, and that history and management’s evaluation and monitoring of performance form the basis of estimated fees recorded. Estimates of the total fee to be earned are made based on contract provisions, prior experience with similar contracts or clients, and management’s evaluation of the performance on such contracts. Revenue for time-and-materials contracts is recognized as services are performed, generally on the basis of contract allowable labor hours worked multiplied by the contract-defined billing rates, plus allowable direct costs and indirect cost allocations associated with materials used and other direct expenses incurred in connection with the performance of the contract. Revenue on fixed-price contracts is recognized using a percentage-of-completion method based on actual costs incurred relative to total estimated costs for the contract. These estimated costs are updated during the term of the contract, and may result in revision by the Company of recognized revenue and estimated costs in the period in which they are identified by cumulative catch-up adjustments. Profits on fixed-price contracts result from the difference between incurred costs and revenue earned. Percentage-of-completion contract accounting requires significant judgment relative to assessing risks, estimating contract revenue and costs, and making assumptions for schedule and technical issues. Due to the size and nature of many of our contracts, developing total revenue and cost at completion estimates require the use of significant judgment. Contract costs include direct labor and billable expenses, an allocation of allowable indirect costs, and warranty obligations. Billable expenses are comprised of subcontracting costs and other direct costs that often include, but are not limited to, travel-related costs and telecommunications charges. We recognize revenue and billable expenses from these transactions on a gross basis. Assumptions regarding the length of time to complete the contract also include expected increases in wages and prices for materials. Estimates of total contract revenue and costs are monitored during the term of the contract and are subject to revision as the contract progresses. Anticipated losses on contracts are recognized in the period they are deemed probable and can be reasonably estimated. Anticipated contract losses recorded for the year ended December 31, 2016 and 2015 were $1 million and $2 million, respectively. Prior to January 1, 2015, the Company’s accounting policy was to record losses under contracts in accordance with ASC 605-10-S99 whereby losses were recorded over the contract life. For the year ended December 31, 2016, the recognized amounts related to changes in estimates at completion represented a net increase to revenue and operating income of $18 million, of which $4 million was directly related to favorable performance on contracts with award fees. Amounts related to changes in estimates at completion for the year ended December 31, 2015 represented a net increase to revenue and operating income of $10 million, of which $5 million was directly related to favorable performance on contracts with award fees. Prior to January 1, 2015, the Company’s accounting policy was to record revenue and operating income in accordance with ASC 605-10-S99 whereby award fees were recognized only when awarded by the customer. The Company’s contracts may include the delivery of a combination of one or more of the Company’s service offerings. In these situations, the Company determines whether such arrangements with multiple service offerings should be treated as separate units of accounting based on how the elements are bid or negotiated, whether the customer can accept separate elements of the arrangement, and the relationship between the pricing on the elements individually and combined. Included in unbilled receivables, a component of receivables, net, are certain restructuring costs related to the performance of our U.S. government contracts which are required to be recorded under GAAP but are not currently allocable to contracts. Such costs are expensed outside of our indirect rates and recognized as revenue for the portion we expect to be recoverable in our rates. At both December 31, 2016 and 2015 these receivables were approximately $11 million and are allocated to contracts when they are paid or otherwise agreed. We regularly assess the probability of recovery of these costs. This assessment requires us to make assumptions about the extent of cost recovery under our contracts and the amount of future contract activity. If the level of backlog in the future does not support the continued expensing of these costs, the profitability of our remaining contracts could be adversely affected. Revenue and profit in connection with contracts to provide services to the U.S. government that contain collection risk because the contracts are incrementally funded and subject to the availability of funds appropriated are deferred until a contract modification is obtained, indicating that adequate funds are available to the contract or task order.
Cost of Revenue	Cost of Revenue: Cost of revenue primarily consists of compensation expenses for program personnel, the fringe benefits associated with this compensation, other direct expenses incurred to complete programs, including cost of materials and subcontract efforts.
Selling, General, and Administrative Expenses	Selling, General, and Administrative Expenses: Selling, general and administrative expenses are expensed as incurred.
Share-Based Compensation	Share-Based Compensation: Certain key employees of Engility participate in share-based compensation plans. We follow the fair value based method of accounting for share-based employee compensation, which requires us to expense all share-based employee compensation. We issue performance shares, restricted stock units (RSUs) and non-qualified stock options under our existing plans to employees of the Company. Compensation expense is recognized for the entire award, net of estimated forfeitures, on a straight line basis over the requisite service period, which is generally three years, based on the grant date fair value.
Income Taxes	Income Taxes: We account for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are recorded for the future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a tax rate change on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. We record valuation allowances to reduce net deferred tax assets to the amount considered more likely than not to be realized. Changes in estimates of future taxable income can materially change the amount of such valuation allowances. We also recognize liabilities for uncertain tax positions when it is more likely than not that a tax position will not be sustained upon ultimate settlement with a taxing authority. If a tax position does not meet the “more-likely-than-not” recognition threshold, despite our belief that our filing position is supportable, the benefit of that tax position is not recognized. At December 31, 2016 and 2015, we had long-term net deferred tax assets of $232 million and $235 million, respectively. Deferred income taxes are determined separately for each of our tax-paying entities in each tax jurisdiction. In assessing the need for a valuation allowance, we considered all available positive and negative evidence, including the future reversal of existing temporary timing differences (deferred tax liabilities), taxable income in carryback years, the feasibility of tax planning strategies and estimated future taxable income. Positive evidence considered in connection with evaluating whether a valuation allowance is required includes the historic ability to utilize deferred tax assets before they expire and future forecasts. In order to realize the deferred tax assets, the Company needs to generate approximately $457 million of pre-tax income over the next 13 years. The Company believes this level of pre-tax income will be achievable. If management determines that a deferred tax asset is not “more likely than not” to be realized, a valuation allowance will be recorded through the income tax provision to reduce the deferred tax asset to an appropriate level in that period. On the basis of this evaluation, as of December 31, 2016, management has determined it is more likely than not a portion of state deferred tax assets, capital loss carryforwards, charitable donations, and foreign tax credits will not be realized and has recorded a $1 million valuation allowance against them. A change in the ability of our operations to continue to generate future taxable income could affect our ability to realize the future tax deductions underlying our deferred tax assets, and require us to provide a valuation allowance against our deferred tax assets. The recognition of a valuation allowance would result in a reduction to net income and, if significant, could have a material impact on our effective tax rate, results of operations and financial position in any given period.
Cash and Cash Equivalents	Cash and Cash Equivalents: Cash and cash equivalents represent cash that is directly attributable to the Company. Cash equivalents consist of highly liquid investments with an original maturity of three months or less at the time of purchase.
Property, Plant and Equipment	Property, Plant and Equipment: Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is computed by applying the straight-line method to the estimated useful lives of the related assets. Useful lives for buildings are 30 years. Useful lives for leasehold improvements range from 5 to 23 years and useful lives for machinery, equipment, furniture and fixtures range from 3 to 10 years. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the improvements. When property or equipment is retired or otherwise disposed of, the net book value of the asset is removed from our balance sheet and the net gain or loss is included in the determination of operating income. Maintenance and repairs are charged to expense as incurred.
Goodwill	Goodwill: We record goodwill in connection with the acquisition of businesses when the purchase price exceeds the fair values of the assets acquired and liabilities assumed. Generally, the largest intangible assets from the businesses that we acquire are the assembled workforces, which includes the human capital of the management, administrative, marketing and business development, engineering and technical employees of the acquired businesses. The success of our businesses, including our ability to retain existing business (revenue arrangements) and to compete successfully for and win new business (revenue arrangements), is primarily dependent on the management, marketing and business development, contracting, engineering and technical skills and knowledge of our employees, rather than on productive capital (plant and equipment, and technology and intellectual property). Additionally, for a significant portion of its businesses, our ability to attract and retain employees who have U.S. government security clearances, particularly those of top-secret and above, is critical to our success, and is often a prerequisite for retaining existing revenue arrangements and pursuing new ones. Therefore, because intangible assets for assembled workforces are part of goodwill in accordance with the accounting standards for business combinations, the substantial majority of the intangible assets for our business acquisitions are recognized as goodwill. Additionally, the value assigned to goodwill for our business acquisitions also includes the value that we expect to realize from cost reduction measures that we implement for our acquired businesses. The carrying value of goodwill is not amortized, but is tested for impairment annually as of November 30 as well as whenever events or changes in circumstances indicate that the carrying amount may not be recoverable using a two-step process for each reporting unit. A reporting unit is an operating segment, as defined by the segment reporting accounting standards, or a component of an operating segment. A component of an operating segment is a reporting unit if the component constitutes a business for which discrete financial information is available and is reviewed by operating segment management. Effective October 2016, we streamlined our structure from seven to five groups, each led by a senior vice president. We made this change to align more closely with our customers’ missions, increase customer intimacy, and eliminate overlap and redundancy. Upon our realignment, the Company combined the goodwill of the units that were consolidated. During 2015, goodwill was allocated to seven reporting units. Upon our acquisition of TASC in February 2015, the Company allocated the goodwill to each of our seven reporting units using relative fair value. Relative fair value was determined based on each reporting unit’s expected contribution to the Company’s projected earnings before interest and taxes (EBIT). The Company does not aggregate any reporting units when evaluating goodwill for impairment. The first step in the process is to identify any potential impairment by comparing the carrying value of a reporting unit including goodwill and its fair value. We determine the fair value of the reporting units using a hybrid method valuation approach which includes (1) the Income Approach (also referred to as a discounted cash flow or DCF), and (2) the Guideline Public Company Method. If a potential impairment is identified, the second step is to measure the impairment loss by comparing the implied fair value of goodwill with the carrying value of goodwill of the reporting units.
Identifiable Intangible Assets	Identifiable Intangible Assets: As part of the accounting for our business acquisitions, identifiable intangible assets are recognized as assets if they arise from contractual or other legal rights, or if they are capable of being separated or divided from the acquired business and sold, transferred, licensed, rented or exchanged. We do not recognize any intangible assets apart from goodwill for the assembled workforces of our business acquisitions. Identifiable intangible assets include customer contractual relationships, contractual backlog and technology. The initial measurement of these intangible assets is based on their fair values. The most significant identifiable intangible asset that is separately recognized for our business acquisitions is customer contractual relationships. All of our customer relationships are established through written customer contracts (revenue arrangements). The fair value for customer contractual relationships is determined, as of the date of acquisition, based on estimates and judgments regarding expectations for the estimated future after-tax earnings and cash flows (including cash flows for working capital) arising from the follow-on revenue on contract (revenue arrangement) renewals expected from the customer contractual relationships over their estimated lives, including the probability of expected future contract renewals and revenue, less a contributory assets charge, all of which is discounted to present value. Identifiable intangible assets are: (1) tested for impairment whenever events or changes in circumstances indicate that the carrying amount of these assets may not be recoverable and (2) amortized over their estimated useful lives as the economic benefits are consumed, ranging from 1 to 20 years. We evaluate the carrying amount and the remaining useful lives of identifiable intangible assets on a quarterly basis at the asset group level. To the extent events or changes in circumstances indicate the carrying amount of these assets may not be recoverable, we test recoverability based on our projection of the undiscounted future operating cash flows of the related asset group. To the extent such projections indicate that future undiscounted cash flows are not sufficient to recover the carrying amount, we recognize a non-cash impairment charge to reduce the carrying amount to fair value. No impairment charges related to identifiable intangible assets were recorded in the three years ending December 31, 2016. To evaluate the reasonableness of the useful lives of the identifiable intangible assets on a quarterly basis, the Company considers whether there have been any significant changes to the nature of the customer contractual relationships, including customers served by Engility, contract types and nature of work performed, subsequent to the date the intangibles were acquired.
Assets and Liabilities Held for Sale	Assets and Liabilities Held for Sale: The Company entered into two separate agreements during the second half of 2016 to sell certain assets and liabilities owned by the Company both of which were completed in the first quarter of 2017. Depreciation for these assets ceased on the date they were designated as held for sale. The held for sale assets and liabilities were recorded at the lower of carrying value or estimated fair value, less an estimate of costs to sell. The estimate of fair value included unobservable inputs (Level 3 fair value). These assets and liabilities were designated as assets held for sale and liabilities held for sale in the accompanying consolidated balance sheets as of December 31, 2016. During the fourth quarter of 2016, the Company agreed to sell certain assets and liabilities of its wholly-owned subsidiary, International Resources Group Ltd. (IRG). The Company completed its sale of IRG on January 6, 2017 which is more fully described in Note 15. In connection with the sale of IRG, and based on the final selling price of the business being less than carrying value of the assets as of December 31, 2016, the Company recorded a non-cash goodwill impairment charge of $10 million in 2016. During the third quarter of 2016, the Company agreed to sell certain long-term assets and designated $2 million as assets held for sale, current, from property, plant and equipment, net, on the Company's consolidated balance sheet at . The carrying amounts of assets and liabilities that were classified as held for sale at December 31, 2016 were as follows: Assets held for sale, current: Cash and cash equivalents $ 1,864 Receivables, net 14,886 Other current assets 3,492 Assets held for sale, current $ 20,242 Assets held for sale: Property, plant and equipment, net $ 868 Goodwill 4,849 Identifiable intangible assets, net 6,245 Assets held for sale $ 11,962 Liabilities held for sale, current: Accounts payable, trade $ 727 Accrued expenses 3,268 Advance payments and billings in excess of costs incurred 271 Other current liabilities 75 Liabilities held for sale, current $ 4,341 Liabilities held for sale: Other liabilities $ 1,084 Liabilities held for sale $ 1,084
Accounts Payable	Accounts Payable: Accounts payable for the periods as of December 31, 2016 and 2015 includes $3 million and $26 million, respectively, for which payment has been remitted to the vendor, but the checks remain outstanding.
Pension and Defined Benefit Plans	Pension and Defined Benefit Plans: The Company measures plan assets and benefit obligations as of the date of its fiscal year end. Accounting and reporting for the Company's pension and defined benefit plans requires the use of assumptions, including but not limited to, a discount rate and an expected return on assets. These assumptions are reviewed at least annually based on reviews of current plan information and consultation with the Company's independent actuary and the plans’ investment advisor. If these assumptions differ materially from actual results, the Company's obligations under the pension and defined benefit plans could also differ materially, potentially requiring the Company to record an additional liability. The Company's pension and defined benefit plan liabilities are developed from actuarial valuations, which are performed each year.
Derivative Instruments	Derivative Instruments: The Company recognizes derivative instruments as either an asset or liability measured at its fair value. For derivative instruments that have been formally designated as a cash flow hedge, the effective portion of changes in the fair value of the derivative instruments are recorded in accumulated other comprehensive income (loss). Amounts in accumulated other comprehensive income (loss) are reclassified into earnings when interest expense on the underlying borrowings is recognized. The Company had entered into multiple interest rate swap contracts which reduced the exposure to variability in cash flows relating to interest payments on a portion of its outstanding debt payments. These interest rate contracts were designated as cash flow hedges. The effective portion of the derivative’s gain or loss was initially reported in accumulated other comprehensive income (loss) and would be subsequently reclassified into earnings in the same period or periods during which the hedged forecasted transaction affects earnings. The ineffective portion of the gain or loss of a cash flow hedge would be reported in earnings.
Fair Value Measurements	Fair Value Measurements: The Company utilizes fair value measurement guidance prescribed by GAAP to value its financial instruments. The guidance includes a definition of fair value, prescribes methods for measuring fair value, establishes a fair value hierarchy based on the inputs used to measure fair value and expands disclosures about the use of fair value measurements. Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, which are typically based on an entity’s own assumptions, as there is little, if any, related market activity. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. The carrying values of cash and cash equivalents, contract receivables and accounts payable approximate fair value because of the short-term nature of these instruments. The carrying value of the Term Loans, excluding original issue discount, and Notes approximated their fair value at December 31, 2016. The fair value of the Term Loans and Notes are based on quotes from a nationally recognized fixed income trading platform and is considered to be a Level 2 input, measured under GAAP hierarchy.
Earnings Per Share	Earnings per Share: Basic EPS is computed by dividing net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted EPS reflects the weighted-average effect of all potentially dilutive securities outstanding during the periods. Diluted EPS includes the incremental effect of the employee stock purchase plan, restricted stock units, and stock options calculated using the treasury stock method. For the years ended December 31, 2016, 2015 and 2014, 766,935 shares, 570,181 shares and 0 shares, respectively, of common stock were not included in diluted EPS due to their anti-dilutive effects. The following table sets forth the reconciliation of the weighted average shares outstanding and calculation of EPS: Year Ended December 31, 2016 2015 2014 Net income (loss) attributable to Engility $ (10,807 ) $ (235,352 ) $ 35,423 Weighted average number of shares outstanding – Basic 36,730 33,536 17,100 Dilutive effect of share-based compensation outstanding after application of the treasury stock method — — 918 Weighted average number of shares outstanding – Diluted 36,730 33,536 18,018 Earnings (loss) per share attributable to Engility Basic $ (0.29 ) $ (7.02 ) $ 2.07 Diluted $ (0.29 ) $ (7.02 ) $ 1.97
New Accounting Pronouncements	New Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test of Goodwill Impairment, In November 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-18, Restricted Cash—a consensus of the FASB Emerging Issues Task Force In August 2016, the FASB issued Accounting Standards Update ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) In April 2016, the FASB issued ASU No. 2016-10 , Identifying Performance Obligations and Licensing In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting. In February 2016, the FASB issued ASU No. 2016-02, Leases In April 2015, the FASB issued ASU No. 2015-03, Interest—Imputation of Interest Interest—Imputation of Interest: Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements - Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In June 2014, the FASB issued ASU No. 2014-12, Compensation - Stock Compensation (Topic 718)—Accounting for Share-based Payments when Terms of an award Provide That a Performance Target Could be Achieved after the Requisite Service Period In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) Principal versus Agent Considerations (Reporting Revenue Gross Versus Net) , Identifying Performance Obligations and Licensing Revenue from Contracts with Customers – Narrow Scope Improvements and Practical Expedients Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers

Basis of Presentation (Tables)

Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Carrying Amounts of Assets and Liabilities Classified as Held for Sale	The carrying amounts of assets and liabilities that were classified as held for sale at December 31, 2016 were as follows: Assets held for sale, current: Cash and cash equivalents $ 1,864 Receivables, net 14,886 Other current assets 3,492 Assets held for sale, current $ 20,242 Assets held for sale: Property, plant and equipment, net $ 868 Goodwill 4,849 Identifiable intangible assets, net 6,245 Assets held for sale $ 11,962 Liabilities held for sale, current: Accounts payable, trade $ 727 Accrued expenses 3,268 Advance payments and billings in excess of costs incurred 271 Other current liabilities 75 Liabilities held for sale, current $ 4,341 Liabilities held for sale: Other liabilities $ 1,084 Liabilities held for sale $ 1,084
Earnings Per Share	Year Ended December 31, 2016 2015 2014 Net income (loss) attributable to Engility $ (10,807 ) $ (235,352 ) $ 35,423 Weighted average number of shares outstanding – Basic 36,730 33,536 17,100 Dilutive effect of share-based compensation outstanding after application of the treasury stock method — — 918 Weighted average number of shares outstanding – Diluted 36,730 33,536 18,018 Earnings (loss) per share attributable to Engility Basic $ (0.29 ) $ (7.02 ) $ 2.07 Diluted $ (0.29 ) $ (7.02 ) $ 1.97

Business Acquisitions (Tables)

Business Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Summary of Allocation of Purchase Price	The final allocation of purchase price is as follows: Number of Engility shares issued 18,937,765 Share price on February 26, 2015 $ 46.45 Dividend payable to Engility stockholders 11.434 Value of Engility shares issued to TASC stockholders $ 35.016 Equity consideration $ 663,125 Cash $ 25,478 Receivables 149,041 Prepaid and deferred income taxes, current 26,015 Other current assets 26,286 Property, plant and equipment 15,835 Deferred tax assets 175,180 Other assets 5,096 Current portion of long-term debt (4,097 ) Accounts payable, trade (34,503 ) Accrued employment costs (92,396 ) Accrued expenses (33,387 ) Advance payments and billings in excess of costs incurred (18,004 ) Deferred income taxes, current and income taxes payable (248 ) Other current liabilities (32,522 ) Long-term debt (619,227 ) Other long-term liabilities (24,446 ) Identifiable intangible assets 358,300 Goodwill 740,724 $ 663,125
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	The valuation of the identified intangible assets acquired is summarized below: Useful Life (years) Customer contractual relationships 15 $ 333,600 Contractual backlog 1 17,700 Technology 15 7,000 Total intangible assets $ 358,300
Business Acquisition Pro Forma Information	Years Ended December 31, 2015 2014 Revenue $ 2,239,577 $ 2,497,428 Operating (loss) income $ (143,496 ) $ 76,495

Receivables (Tables)

Receivables (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Components of Contract Receivables	The components of contract receivables are presented in the table below. December 31, 2016 2015 Billed receivables $ 97,661 $ 229,358 Unbilled receivables 248,253 163,882 Allowance for doubtful accounts (11,666 ) (11,480 ) Total receivables, net $ 334,248 $ 381,760
Allowance for Doubtful Accounts	The following table details the allowance for doubtful accounts: Year Ended December 31, 2016 2015 2014 Balance at beginning of year $ 11,480 $ 1,482 $ 1,410 Charged to expense 744 10,286 441 Deductions (558 ) (288 ) (369 ) Balance at end of year $ 11,666 $ 11,480 $ 1,482

Goodwill and Identifiable Int28

Goodwill and Identifiable Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amounts of goodwill were as follows: Balance as of January 1, 2015 Goodwill $ 1,319,590 Accumulated impairment losses (675,036 ) 644,554 TASC acquisition 740,724 Impairment charge (292,100 ) Balance as of December 31, 2015 Goodwill 2,060,314 Accumulated impairment losses (967,136 ) 1,093,178 Impairment charge (9,875 ) Goodwill allocated to assets held for sale (4,849 ) Balance as of December 31, 2016 Goodwill 2,055,465 Accumulated impairment losses (977,011 ) $ 1,078,454 The amount of goodwill for each of our reporting units at December 31, 2016 is shown in the following table: Space Systems $ 288,594 Intelligence Solutions 260,129 DoD 242,243 Federal Civilian 187,582 Products 99,906 $ 1,078,454
Information on Identifiable Intangible Assets	Information on our identifiable intangible assets that are subject to amortization is presented in the table below. December 31, 2016 December 31, 2015 Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount (in years) Customer contractual relationships 17 $ 545,229 $ 157,482 $ 387,747 $ 554,330 $ 127,264 $ 427,066 Contractual Backlog 1 21,800 21,800 — 21,800 18,850 2,950 Technology 15 7,000 856 6,144 7,000 389 6,611 Total $ 574,029 $ 180,138 $ 393,891 $ 583,130 $ 146,503 $ 436,627
Amortization Expense Recorded for Identifiable Intangible Assets	Our recorded amortization expense for our identifiable intangible assets is presented in the table below. Year Ended December 31, 2016 2015 2014 Amortization expense $ 36,491 $ 45,222 $ 14,856
Estimated Amortization Expense for Identifiable Intangible Assets	Based on gross carrying amounts at December 31, 2016, our estimate of amortization expense for identifiable intangible assets are presented in the table below. Year Ended December 31, 2017 2018 2019 2020 2021 Amortization expense $ 32,482 $ 32,482 $ 32,482 $ 32,482 $ 32,482

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Schedule of Property, Plant and Equipment	The components of property, plant and equipment are presented in the table below. December 31, 2016 2015 Land $ 900 $ 2,200 Buildings and improvements 850 5,536 Machinery, equipment, furniture and fixtures 28,622 29,101 Leasehold improvements 43,598 22,589 Assets under construction 1,861 16,337 Gross property, plant and equipment 75,831 75,763 Accumulated depreciation and amortization (29,284 ) (31,643 ) Property, plant and equipment, net $ 46,547 $ 44,120
Schedule of Depreciation Expense	Our recorded depreciation expense for property, plant and equipment assets is presented in the table below. Year Ended December 31, 2016 2015 2014 Depreciation expense $ 10,306 $ 13,213 $ 6,097

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Income from Continuing Operations before Income Taxes	Income (loss) before income taxes is summarized in the table below. Year Ended December 31, 2016 2015 2014 Domestic $ (9,285 ) $ (298,644 ) $ 70,267 Foreign 486 338 380 Income before income taxes $ (8,799 ) $ (298,306 ) $ 70,647
Components of Current and Deferred Portions of Provision for Income Taxes from Continuing Operations	The components of our current and deferred portions of the provision for income taxes are presented in the table below. Year Ended December 31, 2016 2015 2014 Current income tax provision (benefit): Federal $ (4,030 ) $ (29,632 ) $ 22,111 State and local 107 (1,569 ) 4,462 Foreign (14 ) 727 (592 ) Subtotal (3,937 ) (30,474 ) 25,981 Deferred income tax provision (benefit): Federal 2,252 (31,830 ) 3,785 State and local (1,089 ) (5,718 ) 871 Foreign 44 (45 ) — Subtotal 1,207 (37,593 ) 4,656 Total provision (benefit) for income taxes $ (2,730 ) $ (68,067 ) $ 30,637
Schedule of Effective Income Tax Rate Reconciliation from Continuing Operations	A reconciliation of the statutory Federal income tax rate to our effective income tax rate is presented in the table below. Year Ended December 31, 2016 2015 2014 Statutory Federal income tax rate 35.0 % 35.0 % 35.0 % State and local income taxes, net of Federal income tax benefit 6.6 1.7 4.9 Goodwill impairment (33.2 ) (18.0 ) — Non-controlling interest 18.8 0.6 (2.3 ) Non-deductible acquisition costs — (0.3 ) 3.7 Federal tax credits 2.5 0.1 — Tax audit settlements and return adjustments (3.3 ) — — Uncertain tax positions 1.3 3.9 2.6 Valuation allowance 3.9 — — Other, net (0.6 ) (0.2 ) (0.5 ) Effective income tax rate 31.0 % 22.8 % 43.4 %
Significant Components of Deferred Tax Assets and Liabilities	The significant components of our deferred tax assets and liabilities are presented in the table below. December 31, 2016 2015 Deferred tax assets: Compensation and benefits $ 26,371 $ 27,648 Unrecognized tax benefits 32,808 35,840 Fixed assets 6,627 6,504 Deferred revenue 12,917 10,469 Reserves 14,396 17,235 Pension 17,958 18,316 Net operating losses 171,969 132,511 Other 21,089 24,538 Gross deferred tax assets 304,135 273,061 Deferred tax liabilities: Goodwill and other intangible assets 49,976 15,562 Income recognition on contracts in process 7,119 15,717 Other 13,769 5,058 Gross deferred tax liabilities 70,864 36,337 Valuation allowance (988 ) (1,327 ) Net deferred tax assets $ 232,283 $ 235,397
Summary of Operating Loss Carryforwards	We and our subsidiaries filed income tax returns in various state and foreign jurisdictions. The Company has available at December 31, 2016, unused Federal and state operating loss carry forwards of $445 million and $412 million, respectively, that may be applied against taxable income and that expire in the years as indicated in the table below. Year of Expiration Federal State 2017-2028 $ — $ 4,974 2029-2031 109,493 85,546 2032-2034 187,519 161,356 2035-2036 147,891 160,386 $ 444,903 $ 412,262
Reconciliation of Change in Unrecognized Income Tax Benefits, Excluding Potential Interest and Penalties	The following table presents a reconciliation of the beginning and ending amounts of unrecognized tax benefits, excluding potential interest and penalties: Year Ended December 31, 2016 2015 2014 Balance at January 1 $ 58,360 $ 67,927 $ 67,559 Additions/reductions for tax positions related to the current year 151 4,139 890 Additions/reductions for tax positions related to prior years — (11,542 ) 51 Lapse of statute of limitations (3,237 ) (2,164 ) (573 ) Balance at December 31 $ 55,274 $ 58,360 $ 67,927

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Based Compensation Expense	Share-based compensation expense is summarized in the table below. Year Ended December 31, 2016 2015 2014 Share-based compensation $ 8,255 $ 9,297 $ 8,470 Income taxes (3,219 ) (3,622 ) (3,453 ) Total after income taxes $ 5,036 $ 5,675 $ 5,017
Summary of Stock Option Activity Changes	The table below presents a summary of our stock option activity changes for the year ended December 31, 2016. Number of Options Weighted- Average Exercise Price Per Share Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2015 24 $ 16.83 6.2 $ 769 Granted — — Forfeited — — Exercised (24 ) 16.83 $ 152 Outstanding and exercisable at December 31, 2016 — $ — — $ —
Summary of Nonvested Restricted Stock Units	The table below presents a summary of our nonvested RSU awards for the year ended December 31, 2016. Number of Units Weighted- Average Grant Date Fair Value (in thousands) Nonvested balance at December 31, 2015 175 $ 34.90 Granted 532 18.92 Forfeited (59 ) 27.00 Vested (77 ) 30.97 Nonvested balance at December 31, 2016 571 $ 20.57 Director RSUs vested but not issued at December 31, 2016 37 $ 31.24
Summary of Nonvested Performance Based Units	The table below presents a summary of our nonvested performance share awards as of December 31, 2016. Number of Shares Weighted- Average Grant Date Fair Value (in thousands) Nonvested balance at December 31, 2015 326 $ 26.69 Granted 411 19.33 Forfeited (90 ) 29.03 Vested (130 ) 18.84 Nonvested balance at December 31, 2016 517 $ 22.86
Summary of Nonvested Performance Retention Based Units	The table below presents a summary of our nonvested performance retention awards as of December 31, 2016. Number of Shares Weighted- Average Grant Date Fair Value (in thousands) Nonvested balance at December 31, 2015 213 $ 32.82 Granted — — Forfeited (57 ) 32.82 Vested (57 ) 32.82 Nonvested balance at December 31, 2016 99 $ 32.82

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Payments under Non-cancelable Operating Leases	The following table presents future minimum base rent payments under non-cancellable operating leases with initial terms in excess of one year at December 31, 2016. Real Estate Equipment Total 2017 $ 27,559 $ 288 $ 27,847 2018 18,006 242 18,248 2019 16,329 225 16,554 2020 15,355 44 15,399 2021 14,283 — 14,283 Thereafter 36,740 — 36,740 Total minimum payments required 128,272 799 129,071 Less: Sublease rentals under non-cancellable leases (2,566 ) — (2,566 ) Net minimum payments required $ 125,706 $ 799 $ 126,505
Schedule of Rent Expense under Non-cancelable Operating Leases	The following table presents rent expense under non-cancellable operating leases. Year Ended December 31, 2016 2015 2014 Rent expense $ 38,945 $ 53,912 $ 23,812

Employee Benefits (Tables)

Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2016
Postemployment Benefits [Abstract]
Net Periodic Pension Cost	Net Periodic Pension Cost DRC Pension Plan TASC Benefit Plan Year Ended December 31, 2016 Year Ended December 31, 2015 For the period from January 31, 2014 to December 31, 2014 Year Ended December 31, 2016 For the period from February 26, 2015 to December 31, 2015 Service cost $ 805 $ — $ — $ — $ — Interest cost on projected benefit obligations 2,543 3,997 3,589 468 470 Expected return on plan assets (3,813 ) (5,833 ) (5,339 ) — — Net loss amortization 292 231 — — — Settlement loss — 3,141 — — — Immediate recognition of benefit cost due to plan termination — — — — 285 Net periodic benefit income (expense) $ (173 ) $ 1,536 $ (1,750 ) $ 468 $ 755
Obligations and Funded Status	Obligations and Funded Status DRC Pension Plan TASC Benefit Plan December 31, December 31, 2016 2015 2016 2015 Change in benefit obligation: Benefit obligation at beginning of year $ 78,665 $ 103,028 $ 18,146 $ — Service cost 805 — — — Acquired benefit obligation — — — 20,925 Interest cost 2,543 3,997 468 470 Benefits paid (4,915 ) (4,826 ) (286 ) (3,330 ) Actuarial loss (gain) 1,506 (5,459 ) (1,873 ) 81 Administrative expenses paid (872 ) (719 ) — — Settlement — (17,356 ) — — Benefit obligation at end of year 77,732 78,665 16,455 18,146 Change in plan assets: Fair value of plan assets at beginning of year 50,130 75,047 — — Actual return on plan assets 3,286 (2,433 ) — — Employer contributions 860 417 286 3,330 Benefits paid (4,915 ) (4,826 ) (286 ) (3,330 ) Administrative expenses paid (872 ) (719 ) — — Settlement — (17,356 ) — — Fair value of plan assets at end of year 48,489 50,130 — — Unfunded status $ (29,243 ) $ (28,535 ) $ (16,455 ) $ (18,146 )
Schedule of Amounts Recognized in Balance Sheet	Amounts recognized in the consolidated balance sheets consist of: DRC Pension Plan TASC Benefit Plan December 31, December 31, 2016 2015 2016 2015 Other current liabilities $ — $ — $ 714 $ 905 Other long-term liabilities 29,243 28,535 15,741 17,241 Net amount recognized $ 29,243 $ 28,535 $ 16,455 $ 18,146
Schedule of Defined Benefit Plan Amounts Recognized in Accumulated Other Comprehensive Income (Loss)	DRC Pension Plan Beginning Balance Net Loss Amortization Experience Loss (Gain) Ending Balance 2016 $ 14,235 $ (292 ) $ 2,033 $ 15,976 2015 $ 14,800 $ (291 ) $ (274 ) $ 14,235 2014 $ — $ — $ 14,800 $ 14,800 TASC Benefit Plan Beginning Balance Net Loss Amortization Experience Loss (Gain) Ending Balance 2016 $ (204 ) $ — $ (1,873 ) $ (2,077 ) 2015 $ — $ — $ (204 ) $ (204 )
Schedule of Assumptions Used to Determine the Benefit Obligations and Net Periodic Benefit Costs	The following assumptions were used to determine the benefit obligations and net periodic benefit costs: DRC Pension Plan TASC Benefit Plan December 31, December 31, 2016 2015 2016 2015 Used to determine benefit obligations: Discount rate 3.95 % 4.17 % 3.54 % 3.44 % Rate of compensation increase N/A N/A N/A N/A DRC Pension Plan TASC Benefit Plan Year Ended December 31, Year Ended December 31, 2016 2015 2014 2016 2015 Used to determine net periodic benefit costs: Discount rate 3.39 % 3.94 % (1) 4.49 % 2.85 % 3.05 % (2) Expected rate of return on assets 8.00 % 8.00 % 8.15 % N/A N/A Rate of compensation increase N/A N/A N/A N/A N/A (1) The discount rate used for the determination of the settlement in 2015 was 4.17%. (2) Represents the discounts rate for the RHRA Plan. The discount rate for the Cash Bonus Plan in 2015 was 0.95%.
Summary of Fair Value Measurement of Plan Assets by Asset Category	The Company’s investment policy includes a periodic review of the DRC Pension Plan’s investment in the various asset classes. The fair value measurement of plan assets by asset category is as follows: Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) December 31, 2016: Cash $ 301 $ 301 $ — $ — Money market funds 1,653 — 1,653 — Equity securities: Common equity securities 7,340 7,340 — — Equity mutual funds 86 86 — — Real estate investment trusts 43 43 — — Exchanged traded funds equity 17,542 17,542 — — Corporate and foreign bonds 15,101 — 15,101 — Hedge funds 6,423 — — 6,423 Total $ 48,489 $ 25,312 $ 16,754 $ 6,423 Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) December 31, 2015: Cash $ 223 $ 223 $ — $ — Money market funds 3,288 3,288 — — Equity securities: Common equity securities 6,482 6,482 — — Preferred equity securities 160 160 — — Equity mutual funds 17,237 17,237 — — Real estate investment trusts 613 613 — — Corporate and foreign bonds 15,689 — 15,689 — Hedge funds 6,438 — — 6,438 Total $ 50,130 $ 28,003 $ 15,689 $ 6,438
Reconciliation of Beginning and Ending Balances of Level 3 Assets	A reconciliation of the beginning and ending balances of Level 3 assets is as follows: Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Managed Futures Hedge Funds Total Balance at January 1, 2015 $ 1,884 $ 6,442 $ 8,326 Actual returns on plan assets related to assets still held at the reporting date (3 ) (340 ) (343 ) Purchases — 336 336 Sales (1,881 ) — (1,881 ) Balance at December 31, 2015 $ — $ 6,438 $ 6,438 Actual returns on plan assets related to assets still held at the reporting date — 325 325 Purchases — 104 104 Sales — (444 ) (444 ) Balance at December 31, 2016 $ — $ 6,423 $ 6,423
Summary of Expected Timing of Benefit Payments	The following table sets forth the expected timing of benefit payments by fiscal year: DRC Pension Plan TASC Benefit Plan Total 2017 $ 4,893 $ 714 $ 5,607 2018 $ 4,938 $ 947 $ 5,885 2019 $ 4,993 $ 1,092 $ 6,085 2020 $ 5,074 $ 1,304 $ 6,378 2021 $ 5,063 $ 1,520 $ 6,583 Five subsequent fiscal years $ 25,245 $ 8,208 $ 33,453

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Redemption Price as Percentage of Principal Amount	Year Percentage 2019 104.438 2020 102.219 2021 and thereafter 100.000
Schedule of Composition of Debt	The composition of our debt at December 31, 2016 and 2015 was as follows: December 31, 2016 2015 Term Loans $ 823,300 $ 1,159,725 Notes 300,000 — Other 461 590 Total debt 1,123,761 1,160,315 Less: current portion of long-term debt (26,947 ) (8,447 ) Less: unamortized original issue discount costs and financing fees (56,821 ) (57,839 ) Long-term debt $ 1,039,993 $ 1,094,029
Summary of Debt Minimum Payments on Term Credit Facility	The following table presents our minimum debt payments under the 2016 Credit Facility and the Indenture. 2017 $ 26,800 2018 26,800 2019 26,800 2020 141,800 2021 6,800 Thereafter 894,300 Total minimum payments required $ 1,123,300

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Summary of Other Terms of Instruments	The other terms of these instruments were as follows: Contract received: Floating interest rate LIBOR (subject to minimum of 1.25%) Contract paid: Fixed interest rates 3.09% - 3.18%
Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents our assets and liabilities that are measured at fair value on a recurring basis: Fair December 31, 2016 December 31, 2015 Interest rate swap liability Level 2 $ — $ 3,590

Restructuring and Integration36

Restructuring and Integration Costs (Tables)	12 Months Ended
	Dec. 31, 2016
Restructuring And Related Activities [Abstract]
Summary of Restructuring and Integration Costs	The activity and balance of the liability accounts for the years ended December 31, 2016, 2015 and 2014 are as follows: Severance and Related Costs Other Restructuring Costs Total Balance as of January 1, 2014 $ 337 $ 7,533 $ 7,870 Additions 1,134 — 1,134 Cash payments (1,103 ) (1,497 ) (2,600 ) Balance as of December 31, 2014 $ 368 $ 6,036 $ 6,404 Additions 14,614 6,476 21,090 Cash payments (10,976 ) (3,041 ) (14,017 ) Balance as of December 31, 2015 $ 4,006 $ 9,471 $ 13,477 Additions 9,357 2,186 11,543 Cash payments (12,059 ) (6,704 ) (18,763 ) Other adjustments — (2,429 ) (2,429 ) Balance as of December 31, 2016 $ 1,304 $ 2,524 $ 3,828 Amounts recognized in the consolidated balance sheets as of December 31, 2016 and 2015 consist of: Severance and Related Costs Other Restructuring Costs Total December 31, 2015 Other current liabilities $ 4,006 $ 5,392 $ 9,398 Other liabilities — 4,079 4,079 Amount recognized $ 4,006 $ 9,471 $ 13,477 December 31, 2016 Current liabilities $ 1,304 $ 2,524 $ 3,828 Amount recognized $ 1,304 $ 2,524 $ 3,828

Separate Financial Informatio37

Separate Financial Information of Subsidiary Guarantor of Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Supplemental Condensed Consolidating Balance Sheet	SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF DECEMBER 31, 2016 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 31,124 $ 385 $ 16,727 $ — $ 48,236 Receivables, net — 280,709 34,655 18,884 — 334,248 Intercompany receivables — 83,739 — 758 (84,497 ) — Prepaid income taxes — 5,211 — 219 — 5,430 Assets held for sale, current — 2,332 17,910 — — 20,242 Other current assets — 22,226 506 2,242 — 24,974 Total current assets — 425,341 53,456 38,830 (84,497 ) 433,130 Property, plant and equipment, net — 40,071 6,345 131 — 46,547 Goodwill — 1,020,027 58,427 — — 1,078,454 Identifiable intangible assets, net — 359,465 34,426 — — 393,891 Deferred tax assets — 213,296 18,987 — — 232,283 Assets held for sale — — 11,962 — — 11,962 Investment in subsidiaries 704,805 89,543 29,248 — (823,596 ) — Other assets — 2,292 — — — 2,292 Total assets $ 704,805 $ 2,150,035 $ 212,851 $ 38,961 $ (908,093 ) $ 2,198,559 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 26,947 $ — $ — $ — $ 26,947 Accounts payable, trade — 43,848 37 58 — 43,943 Intercompany payable — 758 83,739 — (84,497 ) — Accrued employment costs — 87,199 4,530 7,131 — 98,860 Accrued expenses — 76,520 — 350 — 76,870 Advance payments and billings in excess of costs incurred — 33,259 — — — 33,259 Deferred income taxes, current and income tax liabilities — — — 230 (21 ) 209 Liabilities held for sale, current — — 4,341 — — 4,341 Other current liabilities — 34,398 47 1,944 21 36,410 Total current liabilities — 302,929 92,694 9,713 (84,497 ) 320,839 Long-term debt — 1,039,993 — — — 1,039,993 Income tax liabilities — 64,852 — — — 64,852 Liabilities held for sale — — 1,084 — — 1,084 Other liabilities — 37,456 29,530 — — 66,986 Total liabilities $ — $ 1,445,230 $ 123,308 $ 9,713 $ (84,497 ) $ 1,493,754 Shareholders' equity 704,805 704,805 89,543 29,248 (823,596 ) 704,805 Total liabilities and equity $ 704,805 $ 2,150,035 $ 212,851 $ 38,961 $ (908,093 ) $ 2,198,559 SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF DECEMBER 31, 2015 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 18,313 $ 29 $ 11,680 $ — $ 30,022 Receivables, net — 314,917 44,665 22,178 — 381,760 Intercompany receivables — 4,983 — — (4,983 ) — Prepaid income taxes — 4,811 — 192 — 5,003 Other current assets — 22,731 3 1,921 — 24,655 Total current assets — 365,755 44,697 35,971 (4,983 ) 441,440 Property, plant and equipment, net — 37,415 6,344 361 — 44,120 Goodwill — 1,034,751 58,427 — — 1,093,178 Identifiable intangible assets, net — 399,570 37,057 — — 436,627 Deferred tax assets — 210,727 24,670 — — 235,397 Investment in subsidiaries 706,133 141,630 23,401 — (871,164 ) — Other assets — 2,229 982 — — 3,211 Total assets $ 706,133 $ 2,192,077 $ 195,578 $ 36,332 $ (876,147 ) $ 2,253,973 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 8,447 $ — $ — $ — $ 8,447 Accounts payable, trade — 50,468 3,628 249 — 54,345 Intercompany payable — — 2,030 2,953 (4,983 ) — Accrued employment costs — 64,463 9,789 7,459 — 81,711 Accrued expenses — 76,606 5,809 350 — 82,765 Advance payments and billings in excess of costs incurred — 48,876 329 — — 49,205 Deferred income taxes, current and income tax liabilities — 447 — 248 — 695 Other current liabilities — 34,590 31 1,672 — 36,293 Total current liabilities — 283,897 21,616 12,931 (4,983 ) 313,461 Long-term debt — 1,094,029 — — — 1,094,029 Income tax liabilities — 68,000 — — — 68,000 Other liabilities — 40,018 32,332 — — 72,350 Total liabilities $ — $ 1,485,944 $ 53,948 $ 12,931 $ (4,983 ) $ 1,547,840 Shareholders' equity 706,133 706,133 141,630 23,401 (871,164 ) 706,133 Total liabilities and equity $ 706,133 $ 2,192,077 $ 195,578 $ 36,332 $ (876,147 ) $ 2,253,973
Supplemental Condensed Consolidating Statement of Operations and Comprehensive Income (Loss)	SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE YEAR ENDED DECEMBER 31, 2016 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,730,876 $ 191,381 $ 154,166 $ — $ 2,076,423 Costs and expenses Cost of revenue — 1,423,013 213,650 141,181 — 1,777,844 Selling, general and administrative expenses — 132,476 30,703 3,059 — 166,238 Goodwill impairment — 9,875 — — — 9,875 Total costs and expenses — 1,565,364 244,353 144,240 — 1,953,957 Operating income (loss) — 165,512 (52,972 ) 9,926 — 122,466 Interest expense, net — 131,185 — — — 131,185 Other income (expenses), net — 135 (1 ) (214 ) — (80 ) Income in equity investments in subsidiaries (10,807 ) (52,259 ) 4,974 — 58,092 — Income (loss) before income taxes (10,807 ) (17,797 ) (47,999 ) 9,712 58,092 (8,799 ) Benefit for income taxes — (6,990 ) 4,260 — — (2,730 ) Net income (loss) (10,807 ) (10,807 ) (52,259 ) 9,712 58,092 (6,069 ) Less: Net income attributable to non-controlling interest — — — 4,738 — 4,738 Net income (loss) attributable to Engility $ (10,807 ) $ (10,807 ) $ (52,259 ) $ 4,974 $ 58,092 $ (10,807 ) Net income (loss) $ (10,807 ) $ (10,807 ) $ (52,259 ) $ 9,712 $ 58,092 $ (6,069 ) Other comprehensive income — 2,191 173 — — 2,364 Comprehensive income (loss) (10,807 ) (8,616 ) (52,086 ) 9,712 58,092 (3,705 ) Less: Net income attributable to non-controlling interest — — — 4,738 — 4,738 Comprehensive income (loss) attributable to Engility $ (10,807 ) $ (8,616 ) $ (52,086 ) $ 4,974 $ 58,092 $ (8,443 ) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE LOSS FOR THE YEAR ENDED DECEMBER 31, 2015 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,622,029 $ 325,926 $ 156,704 $ (19,036 ) $ 2,085,623 Costs and expenses Cost of revenue — 1,384,997 270,790 142,958 (19,036 ) 1,779,709 Selling, general and administrative expenses — 163,019 36,540 3,703 — 203,262 Goodwill impairment — 183,577 108,523 — — 292,100 Total costs and expenses — 1,731,593 415,853 146,661 (19,036 ) 2,275,071 Operating income (loss) — (109,564 ) (89,927 ) 10,043 — (189,448 ) Interest expense, net — 110,148 — (5 ) — 110,143 Other income (expenses), net — 1,289 (4 ) — — 1,285 Income in equity investments in subsidiaries (235,352 ) (60,844 ) 4,935 — 291,261 — Income (loss) before income taxes (235,352 ) (279,267 ) (84,996 ) 10,048 291,261 (298,306 ) Benefit for income taxes — (43,915 ) (24,152 ) — — (68,067 ) Net income (loss) (235,352 ) (235,352 ) (60,844 ) 10,048 291,261 (230,239 ) Less: Net income attributable to non-controlling interest — — — 5,113 — 5,113 Net income (loss) attributable to Engility $ (235,352 ) $ (235,352 ) $ (60,844 ) $ 4,935 $ 291,261 $ (235,352 ) Net income (loss) $ (235,352 ) $ (235,352 ) $ (60,844 ) $ 10,048 $ 291,261 $ (230,239 ) Other comprehensive income — 1,428 361 — — 1,789 Comprehensive income (loss) (235,352 ) (233,924 ) (60,483 ) 10,048 291,261 (228,450 ) Less: Net income attributable to non-controlling interest — — — 5,113 — 5,113 Comprehensive income (loss) attributable to Engility $ (235,352 ) $ (233,924 ) $ (60,483 ) $ 4,935 $ 291,261 $ (233,563 ) SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME FOR THE YEAR ENDED DECEMBER 31, 2014 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ — $ 1,228,538 $ 148,243 $ (9,690 ) $ 1,367,091 Costs and expenses Cost of revenue — — 1,040,552 138,419 (9,690 ) 1,169,281 Selling, general and administrative expenses — — 113,216 1,674 — 114,890 Total costs and expenses — — 1,153,768 140,093 (9,690 ) 1,284,171 Operating income — — 74,770 8,150 — 82,920 Interest expense, net — — 12,803 (4 ) — 12,799 Other income, net — — 526 — — 526 Income in equity investments in subsidiaries 35,423 — 3,567 — (38,990 ) — Income before income taxes 35,423 — 66,060 8,154 (38,990 ) 70,647 Provision for income taxes — — 30,637 — — 30,637 Net income 35,423 — 35,423 8,154 (38,990 ) 40,010 Less: Net income attributable to non-controlling interest — — — 4,587 — 4,587 Net income attributable to Engility $ 35,423 $ — $ 35,423 $ 3,567 $ (38,990 ) $ 35,423 Net income $ 35,423 $ — $ 35,423 $ 8,154 $ (38,990 ) $ 40,010 Other comprehensive loss — — (9,018 ) — — (9,018 ) Comprehensive income 35,423 — 26,405 8,154 (38,990 ) 30,992 Less: Net income attributable to non-controlling interest — — — 4,587 — 4,587 Comprehensive income attributable to Engility $ 35,423 $ — $ 26,405 $ 3,567 $ (38,990 ) $ 26,405
Supplemental Condensed Consolidating Statement of Cash Flows	SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE YEAR ENDED DECEMBER 31, 2016 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ 163,136 $ (81,354 ) $ 12,623 $ — $ 94,405 Investing activities: Acquisitions, net of cash acquired — — — — — — Capital expenditures — (21,446 ) — — — (21,446 ) Net cash used in investing activities — (21,446 ) — — — (21,446 ) Financing activities: Gross borrowings from issuance of long-term debt — 1,180,000 — — — 1,180,000 Repayment of long-term debt — (1,215,754 ) — — — (1,215,754 ) Gross borrowings from revolving credit facility — 137,000 — — — 137,000 Repayments of revolving credit facility — (137,000 ) — — — (137,000 ) Debt issuance costs — (9,988 ) — — — (9,988 ) Equity issuance costs — — — — — — Proceeds from share-based payment arrangements 214 — — — — 214 Payment of employee withholding taxes on share- based compensation (1,779 ) — — — — (1,779 ) Excess tax deduction on share-based compensation — — — — — — Dividends paid (1,709 ) — — — — (1,709 ) Distributions to non-controlling interest member — — — (3,865 ) — (3,865 ) Due (to) from subsidiaries 3,274 (81,273 ) 81,710 (3,711 ) — — Net cash used in financing activities — (127,015 ) 81,710 (7,576 ) — (52,881 ) Change in cash from assets held for sale — (1,864 ) — — — (1,864 ) Net change in cash and cash equivalents — 12,811 356 5,047 — 18,214 Cash and cash equivalents, beginning of period — 18,313 29 11,680 — 30,022 Cash and cash equivalents, end of period $ — $ 31,124 $ 385 $ 16,727 $ — $ 48,236 SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE YEAR ENDED DECEMBER 31, 2015 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ 45,633 $ (10,754 ) $ 13,539 $ — $ 48,418 Investing activities: Acquisitions, net of cash acquired — 25,478 — — — 25,478 Capital expenditures — (19,610 ) — — — (19,610 ) Net cash provided by investing activities — 5,868 — — — 5,868 Financing activities: Gross borrowings from issuance of long-term debt — 585,000 — — — 585,000 Repayment of long-term debt — (403,674 ) — — — (403,674 ) Gross borrowings from revolving credit facility — 157,000 — — — 157,000 Repayments of revolving credit facility — (115,000 ) — — — (115,000 ) Debt issuance costs — (42,425 ) — — — (42,425 ) Equity issuance costs (2,590 ) — — — — (2,590 ) Proceeds from share-based payment arrangements 279 — — — — 279 Payment of employee withholding taxes on share- based compensation (8,021 ) — — — — (8,021 ) Excess tax deduction on share-based compensation 5,530 — — — — 5,530 Dividends paid (204,304 ) — — — — (204,304 ) Distributions to non-controlling interest member — — — (3,182 ) — (3,182 ) Due (to) from subsidiaries 209,106 (214,089 ) 7,656 (2,673 ) — Net cash used in financing activities — (33,188 ) 7,656 (5,855 ) — (31,387 ) Net change in cash and cash equivalents — 18,313 (3,098 ) 7,684 — 22,899 Cash and cash equivalents, beginning of period — — 3,127 3,996 — 7,123 Cash and cash equivalents, end of period $ — $ 18,313 $ 29 $ 11,680 $ — $ 30,022 SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE YEAR ENDED DECEMBER 31, 2014 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ — $ 104,849 $ (2,490 ) $ — $ 102,359 Investing activities: Acquisitions, net of cash acquired — — (207,250 ) — — (207,250 ) Capital expenditures — — (5,436 ) — — (5,436 ) Net cash used in investing activities — — (212,686 ) — — (212,686 ) Financing activities: Gross borrowings from issuance of long-term debt — — 75,000 — — 75,000 Repayment of long-term debt — — (13,750 ) — — (13,750 ) Gross borrowings from revolving credit facility — — 482,500 — — 482,500 Repayments of revolving credit facility — — (448,000 ) — — (448,000 ) Debt issuance costs — — (1,131 ) — — (1,131 ) Equity issuance costs — — — — — — Proceeds from share-based payment arrangements 1,479 — — — — 1,479 Payment of employee withholding taxes on share- based compensation (2,371 ) — — — — (2,371 ) Excess tax deduction on share-based compensation 1,707 — — — — 1,707 Dividends paid — — — — — — Distributions to non-controlling interest member — — — (6,987 ) — (6,987 ) Due (to) from subsidiaries (815 ) — (950 ) 1,765 — — Net cash provided by financing activities — — 93,669 (5,222 ) — 88,447 Net change in cash and cash equivalents — — (14,168 ) (7,712 ) — (21,880 ) Cash and cash equivalents, beginning of period — — 17,295 11,708 — 29,003 Cash and cash equivalents, end of period $ — $ — $ 3,127 $ 3,996 $ — $ 7,123

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details)	Nov. 30, 2016USD ($)reporting_unit	Sep. 30, 2016USD ($)Segment	Oct. 31, 2016Segment	Feb. 28, 2015Segment	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)employeeCountryshares	Dec. 31, 2015USD ($)Segmentshares	Dec. 31, 2014USD ($)shares	Feb. 26, 2015employee
Basis of Presentation [Line Items]
Number of individuals employed | employee						9,100
Number of countries in which Company operates | Country						49
Pre-tax income to correct an error related to prior year						$ (2,000,000)
Loss on contract services						1,000,000	$ 2,000,000
Unbilled receivables restructuring costs incurred					$ 11,000,000	$ 11,000,000	11,000,000
Period in which compensation cost estimated to be recognized						3 years
Long-term net deferred tax assets					235,397,000	$ 232,283,000	235,397,000
Necessary pre-tax income to realize tax benefits						$ 457,000,000
Period for recognition						13 years
Valuation allowance					1,327,000	$ 988,000	$ 1,327,000
Number of reporting units	5	7	5				7
Impairment charges of identifiable intangible assets						0	$ 0	$ 0
Goodwill impairment	$ 0				292,000,000	9,875,000	292,100,000
Long-term assets held for sale		$ 2,000,000				20,242,000
Accumulated depreciation		$ 1,000,000			31,643,000	29,284,000	31,643,000
Outstanding checks in accounts payable					$ 26,000,000	$ 3,000,000	$ 26,000,000
Anti-dilutive securities | shares						766,935	570,181	0
International Resources Group Ltd. [Member] | Discontinued Operations, Held-for-sale [Member]
Basis of Presentation [Line Items]
Goodwill impairment						$ 10,000,000
TASC [Member]
Basis of Presentation [Line Items]
Number of individuals employed | employee									4,000
Number of reporting units with relative fair value goodwill | Segment				7
Minimum [Member]
Basis of Presentation [Line Items]
Useful lives of identifiable intangible assets						1 year
Maximum [Member]
Basis of Presentation [Line Items]
Useful lives of identifiable intangible assets						20 years
Building [Member]
Basis of Presentation [Line Items]
Useful lives of assets						30 years
Building and Improvements [Member] | Minimum [Member]
Basis of Presentation [Line Items]
Useful lives of assets						5 years
Building and Improvements [Member] | Maximum [Member]
Basis of Presentation [Line Items]
Useful lives of assets						23 years
Machinery, Equipment, Furniture and Fixtures [Member] | Minimum [Member]
Basis of Presentation [Line Items]
Useful lives of assets						3 years
Machinery, Equipment, Furniture and Fixtures [Member] | Maximum [Member]
Basis of Presentation [Line Items]
Useful lives of assets						10 years
Contracts Accounted for under Percentage of Completion [Member]
Basis of Presentation [Line Items]
Financial effect of change in estimate, increase to revenue and operating income (loss)						$ 18,000,000	$ 10,000,000
Award Fees Contracts Accounted For Under Cost-Plus Type Contracts [Member] | Contracts Accounted for under Percentage of Completion [Member]
Basis of Presentation [Line Items]
Financial effect of change in estimate, increase to revenue and operating income (loss)						$ 4,000,000	$ 5,000,000
Engility Corporation [Member]
Basis of Presentation [Line Items]
Capital stock owning percentage by parent						100.00%
Forfeiture Support Associates LLC [Member]
Basis of Presentation [Line Items]
Non-controlling equity interest ownership percentage						50.10%

Basis of Presentation - Carryin

Basis of Presentation - Carrying Amounts of Assets and Liabilities Classified as Held for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016
Assets held for sale, current:
Assets held for sale, current	$ 20,242	$ 2,000
Assets held for sale:
Assets held for sale	11,962
Liabilities held for sale, current:
Liabilities held for sale, current	4,341
Liabilities held for sale:
Liabilities held for sale	1,084
Cash and Cash Equivalents [Member]
Assets held for sale, current:
Assets held for sale, current	1,864
Receivables Net [Member]
Assets held for sale, current:
Assets held for sale, current	14,886
Property, Plant and Equipment Net [Member]
Assets held for sale:
Assets held for sale	868
Goodwill [Member]
Assets held for sale:
Assets held for sale	4,849
Identifiable Intangible Assets Net [Member]
Assets held for sale:
Assets held for sale	6,245
Other Current Assets [Member]
Assets held for sale, current:
Assets held for sale, current	3,492
Accounts Payable Trade [Member]
Liabilities held for sale, current:
Liabilities held for sale, current	727
Accrued Expenses [Member]
Liabilities held for sale, current:
Liabilities held for sale, current	3,268
Advance Payments and Billings in Excess of Costs Incurred [Member]
Liabilities held for sale, current:
Liabilities held for sale, current	271
Other Current Liabilities [Member]
Liabilities held for sale, current:
Liabilities held for sale, current	75
Other NonCurrent Liabilities [Member]
Liabilities held for sale:
Liabilities held for sale	$ 1,084

Basis of Presentation - Earning

Basis of Presentation - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Net income (loss) attributable to Engility	$ (10,807)	$ (235,352)	$ 35,423
Weighted average number of shares outstanding – Basic	36,730	33,536	17,100
Dilutive effect of share-based compensation outstanding after application of the treasury stock method			918
Weighted average number of shares outstanding – Diluted	36,730	33,536	18,018
Earnings (loss) per share attributable to Engility
Basic	$ (0.29)	$ (7.02)	$ 2.07
Diluted	$ (0.29)	$ (7.02)	$ 1.97

New Accounting Pronouncements -

New Accounting Pronouncements - Additional Information (Details) $ in Millions	Dec. 31, 2015USD ($)
Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	$ 21

Business Acquisitions - Additio

Business Acquisitions - Additional Information (Details) $ / shares in Units, $ in Thousands	Mar. 06, 2017	Feb. 26, 2015USD ($)employeeboard_member$ / sharesshares	Jan. 31, 2014USD ($)$ / shares	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)employee	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013employee
Business Acquisition [Line Items]
Number of individuals employed | employee						9,100
Common stock ownership, percent		99.00%
Number of board members eligible to be nominated | board_member		11
Shares issued for acquisition							$ 663,125
Dividends paid		$ 204,000				$ 1,709	204,304
Number of board members eligible to be nominated by Engility directors | board_member		7
Number of board members eligible to be nominated, Birch Partners | board_member		4
Acquisition and restructuring related costs						12,000	45,000	$ 18,000
Amortization expense						36,491	45,222	14,856
Goodwill				$ 1,093,178	$ 644,554	1,078,454	1,093,178	644,554
TASC [Member]
Business Acquisition [Line Items]
Number of individuals employed | employee		4,000
Common stock ownership, percent		52.00%
Shares issued for acquisition (in shares) | shares		18,937,765
Shares issued for acquisition		$ 663,000
Fair value of debt assumed		623,000
Cash dividends on common stock		$ 207,000
Dividend paid, per share (in USD per share) | $ / shares		$ 11.434
Common stock ownership, maximum percent, before consensus voting		30.00%
Revenue of acquiree since acquisition date				907,000
Pre-tax net income of acquiree since acquisition				$ 55,000
Goodwill		$ 740,724
TASC [Member] | Minimum [Member]
Business Acquisition [Line Items]
Common stock ownership, percent required to consensus voting		21.00%
TASC [Member] | Maximum [Member]
Business Acquisition [Line Items]
Common stock ownership, percent required to consensus voting		21.50%
TASC [Member] | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P.
Business Acquisition [Line Items]
Number of board members eligible to be nominated | board_member		4
TASC [Member] | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P. | Minimum [Member]
Business Acquisition [Line Items]
Business combination, period in which ownership can not be transferred		1 year
Business combination, period in which limited ownership can be transferred		4 years
TASC [Member] | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P. | Maximum [Member]
Business Acquisition [Line Items]
Business combination, period in which ownership can not be transferred		3 years
Business combination, period in which limited ownership can be transferred		6 years
TASC [Member] | Scenario 1 | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P.
Business Acquisition [Line Items]
Number of board members eligible to be nominated | board_member		4
TASC [Member] | Scenario 1 | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P. | Minimum [Member]
Business Acquisition [Line Items]
Common stock ownership, percent		50.00%
TASC [Member] | Scenario 2 | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P.
Business Acquisition [Line Items]
Number of board members eligible to be nominated | board_member		2
TASC [Member] | Scenario 2 | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P. | Minimum [Member]
Business Acquisition [Line Items]
Common stock ownership, percent		25.00%
TASC [Member] | Scenario 2 | Birch Partners, LP And Kohlberg Kravis Roberts & Co. L.P. | Maximum [Member]
Business Acquisition [Line Items]
Common stock ownership, percent		50.00%
TASC [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Common stock ownership, percent	51.00%
TASC and DRC [Member]
Business Acquisition [Line Items]
Amortization expense						28,000	$ 36,000	$ 6,000
Dynamics Research Corporation [Member]
Business Acquisition [Line Items]
Number of individuals employed | employee									1,100
Revenue of acquiree since acquisition date					218,000
Pre-tax net income of acquiree since acquisition					9,000
Amortization expense					6,000
Price per share (USD per share) | $ / shares			$ 11.50
Aggregate cash purchase price			$ 207,000
Debt assumed in a business combination			$ 86,000
Goodwill						$ 167,000
Severance and integration related costs					$ 8,000

Business Acquisitions - TASC Ac

Business Acquisitions - TASC Acquisition (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 26, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill		$ 1,078,454	$ 1,093,178	$ 644,554
TASC [Member]
Business Acquisition [Line Items]
Shares issued for acquisition (in shares)	18,937,765
Share price	$ 46.45
Dividend paid, per share (in USD per share)	11.434
Value of Engility shares issued to TASC stockholders	$ 35.016
Equity consideration	$ 663,125
Cash	25,478
Receivables	149,041
Prepaid and deferred income taxes, current	26,015
Other current assets	26,286
Property, plant and equipment	15,835
Deferred tax assets	175,180
Other assets	5,096
Current portion of long-term debt	(4,097)
Accounts payable, trade	(34,503)
Accrued employment costs	(92,396)
Accrued expenses	(33,387)
Advance payments and billings in excess of costs incurred	(18,004)
Deferred income taxes, current and income taxes payable	(248)
Other current liabilities	(32,522)
Long-term debt	(619,227)
Other long-term liabilities	(24,446)
Identifiable intangible assets	358,300
Goodwill	740,724
Net assets acquired	$ 663,125

Business Acquisitions - Intangi

Business Acquisitions - Intangible Assets (Details) - TASC [Member] $ in Thousands	Feb. 26, 2015USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 358,300
Customer Contractual Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Life (years)	15 years
Identifiable intangible assets	$ 333,600
Contractual Backlog [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Life (years)	1 year
Identifiable intangible assets	$ 17,700
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Life (years)	15 years
Identifiable intangible assets	$ 7,000

Business Acquisitions - Pro For

Business Acquisitions - Pro Forma (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition Pro Forma Information [Abstract]
Revenue	$ 2,239,577	$ 2,497,428
Operating (loss) income	$ (143,496)	$ 76,495

Receivables - Additional Inform

Receivables - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk [Line Items]
Revenue from U.S. Government under prime contracts and subcontracts, compared to total revenue	99.00%	99.00%	98.00%
Increase in billed receivables	$ 110
Decrease in unbilled receivables	$ 110
Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Credit risk of total receivables	1.00%

Receivables - Components of Con

Receivables - Components of Contract Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Billed receivables	$ 97,661	$ 229,358
Unbilled receivables	248,253	163,882
Allowance for doubtful accounts	(11,666)	(11,480)
Total receivables, net	$ 334,248	$ 381,760

Receivables - Allowance for Dou

Receivables - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	$ 11,480	$ 1,482	$ 1,410
Charged to expense	744	10,286	441
Deductions	(558)	(288)	(369)
Balance at end of year	$ 11,666	$ 11,480	$ 1,482

Goodwill and Identifiable Int49

Goodwill and Identifiable Intangible Assets - Summary of Goodwill (Details) - USD ($)	Nov. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Feb. 26, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill		$ 2,060,314,000	$ 2,055,465,000	$ 2,060,314,000		$ 1,319,590,000
Accumulated impairment losses		(967,136,000)	(977,011,000)	(967,136,000)		(675,036,000)
Goodwill		1,093,178,000	1,078,454,000	1,093,178,000		$ 644,554,000
Impairment charge	$ 0	$ (292,000,000)	(9,875,000)	(292,100,000)
Goodwill allocated to assets held for sale			$ (4,849,000)
TASC [Member]
Goodwill [Line Items]
Goodwill					$ 740,724,000
Goodwill acquired				$ 740,724,000

Goodwill and Identifiable Int50

Goodwill and Identifiable Intangible Assets - Additional Information (Details)	Nov. 30, 2016USD ($)reporting_unit	Sep. 30, 2016Segment	Nov. 30, 2015reporting_unit	Oct. 31, 2016Segment	Dec. 31, 2015USD ($)reporting_unit	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)Segment
Goodwill [Line Items]
Income approach, percent						50.00%
Guideline public company method, percent							50.00%
Number of reporting units	5	7		5			7
Goodwill impairment charge	$ 0				$ 292,000,000	$ 9,875,000	$ 292,100,000
Number of reporting units with declined estimated fair value | reporting_unit					4
Weighted average long-term growth rate, percent						3.00%	3.00%
Weighted average cost of capital, percent						9.00%	10.00%
Number of reporting units with fair value exceeded carrying value | reporting_unit	5		3
Goodwill impairment analysis, amount of fair value exceeds carrying value						$ 573,000,000
Goodwill impairment analysis, percent fair value exceeds carrying value	36.00%
Goodwill impairment	$ 0				$ 292,000,000	9,875,000	$ 292,100,000
Goodwill allocated to assets held for sale						4,849,000
Accumulated Amortization					$ 146,503,000	180,138,000	146,503,000
Federal Civilian [Member]
Goodwill [Line Items]
Goodwill impairment charge						10,000,000
Goodwill, period decrease						(15,000,000)
Goodwill impairment						10,000,000
International Resources Group Ltd. [Member]
Goodwill [Line Items]
Goodwill impairment charge						9,875,000	183,577,000
Goodwill impairment						9,875,000	$ 183,577,000
Accumulated Amortization						3,000,000
International Resources Group Ltd. [Member] | Identifiable Intangible Assets [Member]
Goodwill [Line Items]
Assets held for sale						9,000,000
International Resources Group Ltd. [Member] | Federal Civilian [Member]
Goodwill [Line Items]
Goodwill allocated to assets held for sale						$ 5,000,000
Minimum [Member]
Goodwill [Line Items]
Goodwill impairment analysis, percent fair value exceeds carrying value	15.00%		20.00%

Goodwill and Identifiable Int51

Goodwill and Identifiable Intangible Assets - Summary of Goodwill by Reporting Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$ 1,078,454	$ 1,093,178	$ 644,554
Space Systems [Member]
Goodwill [Line Items]
Goodwill	288,594
Intelligence Solutions [Member]
Goodwill [Line Items]
Goodwill	260,129
DoD [Member]
Goodwill [Line Items]
Goodwill	242,243
Federal Civilian [Member]
Goodwill [Line Items]
Goodwill	187,582
Products [Member]
Goodwill [Line Items]
Goodwill	$ 99,906

Goodwill and Identifiable Int52

Goodwill and Identifiable Intangible Assets - Information on Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 574,029	$ 583,130
Accumulated Amortization	180,138	146,503
Net Carrying Amount	$ 393,891	436,627
Customer Contractual Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	17 years
Gross Carrying Amount	$ 545,229	554,330
Accumulated Amortization	157,482	127,264
Net Carrying Amount	$ 387,747	427,066
Contractual Backlog [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	1 year
Gross Carrying Amount	$ 21,800	21,800
Accumulated Amortization	$ 21,800	18,850
Net Carrying Amount		2,950
Technology [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	15 years
Gross Carrying Amount	$ 7,000	7,000
Accumulated Amortization	856	389
Net Carrying Amount	$ 6,144	$ 6,611

Goodwill and Identifiable Int53

Goodwill and Identifiable Intangible Assets - Amortization Expense Recorded for Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 36,491	$ 45,222	$ 14,856

Goodwill and Identifiable Int54

Goodwill and Identifiable Intangible Assets - Estimated Amortization Expense for Identifiable Intangible Assets (Details) $ in Thousands	Dec. 31, 2016USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2,017	$ 32,482
2,018	32,482
2,019	32,482
2,020	32,482
2,021	$ 32,482

Property, Plant and Equipment -

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 75,831		$ 75,763
Accumulated depreciation and amortization	(29,284)	$ (1,000)	(31,643)
Property, plant and equipment, net	46,547		44,120
Land [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	900		2,200
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	850		5,536
Machinery, Equipment, Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	28,622		29,101
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	43,598		22,589
Assets Under Construction [Member]
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 1,861		$ 16,337

Property, Plant and Equipment56

Property, Plant and Equipment - Schedule of Depreciation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Depreciation expense	$ 10,306	$ 13,213	$ 6,097

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income from Continuing Operations before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ (9,285)	$ (298,644)	$ 70,267
Foreign	486	338	380
Income (loss) before income taxes	$ (8,799)	$ (298,306)	$ 70,647

Income Taxes - Components of Cu

Income Taxes - Components of Current and Deferred Portions of Provision for Income Taxes from Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income tax provision (benefit):
Federal	$ (4,030)	$ (29,632)	$ 22,111
State and local	107	(1,569)	4,462
Foreign	(14)	727	(592)
Subtotal	(3,937)	(30,474)	25,981
Deferred income tax provision (benefit):
Federal	2,252	(31,830)	3,785
State and local	(1,089)	(5,718)	871
Foreign	44	(45)
Subtotal	1,207	(37,593)	4,656
Total provision (benefit) for income taxes	$ (2,730)	$ (68,067)	$ 30,637

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation from Continuing Operations (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Statutory Federal income tax rate	35.00%	35.00%	35.00%
State and local income taxes, net of Federal income tax benefit	6.60%	1.70%	4.90%
Goodwill impairment	(33.20%)	(18.00%)	0.00%
Non-controlling interest	18.80%	0.60%	(2.30%)
Non-deductible acquisition costs	0.00%	(0.30%)	3.70%
Federal tax credits	2.50%	0.10%	(0.00%)
Tax audit settlements and return adjustments	(3.30%)	(0.00%)	(0.00%)
Uncertain tax positions	1.30%	3.90%	2.60%
Valuation allowance	3.90%	0.00%	0.00%
Other, net	(0.60%)	(0.20%)	(0.50%)
Effective income tax rate	31.00%	22.80%	43.40%

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Compensation and benefits	$ 26,371	$ 27,648
Unrecognized tax benefits	32,808	35,840
Fixed assets	6,627	6,504
Deferred revenue	12,917	10,469
Reserves	14,396	17,235
Pension	17,958	18,316
Net operating losses	171,969	132,511
Other	21,089	24,538
Gross deferred tax assets	304,135	273,061
Deferred tax liabilities:
Goodwill and other intangible assets	49,976	15,562
Income recognition on contracts in process	7,119	15,717
Other	13,769	5,058
Gross deferred tax liabilities	70,864	36,337
Valuation allowance	(988)	(1,327)
Net deferred tax assets	$ 232,283	$ 235,397

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance	$ 988	$ 1,327
Foreign income tax credits	1,000
Excess equity tax benefits	3,000
Unrecognized tax benefits	55,274	58,360	$ 67,927	$ 67,559
Accrued potential interest	10,000	10,000	12,000
Unrecognized tax benefits that would impact effective tax rate	10,000
Anticipated decrease in unrecognized tax benefits over the next 12 months	3,000
Interest expense/benefit included in income tax expense	(1,000)	$ (2,000)	$ 2,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	444,903
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	$ 412,262

Income Taxes Income Taxes - Sum

Income Taxes Income Taxes - Summary of Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2016USD ($)
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	$ 444,903
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	412,262
2017-2028 [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	4,974
2029-2031 [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	109,493
2029-2031 [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	85,546
2032-2034 [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	187,519
2032-2034 [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	161,356
2035-2036 [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	147,891
2035-2036 [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	$ 160,386

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Change in Unrecognized Income Tax Benefits, Excluding Potential Interest and Penalties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 58,360	$ 67,927	$ 67,559
Additions/reductions for tax positions related to the current year	151	4,139	890
Additions/reductions for tax positions related to prior years	0	(11,542)	51
Lapse of statute of limitations	(3,237)	(2,164)	(573)
Ending Balance	$ 55,274	$ 58,360	$ 67,927

Share-Based Compensation - Shar

Share-Based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation	$ 8,255	$ 9,297	$ 8,470
Income taxes	(3,219)	(3,622)	(3,453)
Total after income taxes	$ 5,036	$ 5,675	$ 5,017

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost | $	$ 11
Period for recognition	3 years
Unrecognized compensation cost amortized, 2017 | $	$ 6
Unrecognized compensation cost amortized, 2018 | $	4
Unrecognized compensation cost amortized, 2019 | $	$ 1
Threshold percentage of fair market value of shares under stock options	25.00%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated vesting (in shares) | shares	364,983
Restricted Stock Units (RSUs) [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Waived vesting (in shares) | shares	229,166
Restricted Stock Units (RSUs) [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated vesting (in shares) | shares	43,950
Waived vesting (in shares) | shares	11,790
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance Shares [Member] | 2014 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount	100.00%
Performance Shares [Member] | 2013 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount	127.00%

Share-Based Compensation - Long

Share-Based Compensation - Long Term Performance Plan - Additional Information (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in the period	411,000
Weighted average share price (USD per share)	$ 19.33
Shares vested in period (in shares)	130,000
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Vesting period	3 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average share price (USD per share)	$ 18.92	$ 32.12	$ 43.21
Restricted Stock Units (RSUs) [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Shares granted in the period	506,493
Weighted average share price (USD per share)	$ 18.70
Restricted Stock Units (RSUs) [Member] | Employees [Member] | Period Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	56,524
Shares vested in period (in percentage)	25.00%
Restricted Stock Units (RSUs) [Member] | Employees [Member] | Period Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	175,852
Shares vested in period (in percentage)	50.00%
Restricted Stock Units (RSUs) [Member] | Employees [Member] | Over Period Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	274,117
Restricted Stock Units (RSUs) [Member] | Employees [Member] | Period One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in percentage)	25.00%
Restricted Stock Units (RSUs) [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Shares granted in the period	104,619
Weighted average share price (USD per share)	$ 17.97
Restricted Stock Units (RSUs) [Member] | Chief Executive Officer [Member] | Period Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	50,083
Restricted Stock Units (RSUs) [Member] | Chief Executive Officer [Member] | Over Period Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	54,536
Restricted Stock Units (RSUs) [Member] | Non-management Members Of The Board Of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Shares granted in the period	25,704
Weighted average share price (USD per share)	$ 23.34
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Weighted average share price (USD per share)	$ 19.33	32.29	$ 56.14
Performance Shares [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in the period	411,178
Weighted average share price (USD per share)	$ 19.33
Shares granted at maximum performance level	822,356
Performance period	3 years
Percent of the target grant amount	100.00%
Performance Shares [Member] | Employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount	0.00%
Performance Shares [Member] | Employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount	200.00%
Performance Shares [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in the period	81,803
Weighted average share price (USD per share)	$ 17.97
Shares granted at maximum performance level	163,606
Percent of the target grant amount	100.00%
Performance Retention Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	57,000
Performance Retention Award [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average share price (USD per share)		$ 32.82
Performance period		3 years
Performance Retention Award [Member] | Executive Officer [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount		50.00%
Performance Retention Award [Member] | Executive Officer [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount		200.00%

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Option Activity Changes (Details) - Options [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, outstanding, beginning balance (in shares)	24
Number of options, exercised (in shares)	(24)
Number of options, outstanding, ending balance (in shares)		24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, beginning balance (USD per share)	$ 16.83
Weighted average exercise price, exercised (USD per share)	$ 16.83
Weighted average exercise price, ending balance (USD per share)		$ 16.83
Remaining contractual term, shares outstanding	0 years	6 years 2 months 12 days
Aggregate intrinsic value, outstanding	$ 769
Aggregate intrinsic value, exercised	$ 152
Aggregate intrinsic value, outstanding		$ 769

Share-Based Compensation - Su68

Share-Based Compensation - Summary of Nonvested Restricted Based Units (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Employee RSUs vested (in shares) | shares	(130)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share)	$ 26.69
Weighted-average grant date fair value, granted (USD per share)	19.33
Weighted-average grant date fair value, forfeited (USD per share)	29.03
Weighted average grant date fair value, employee RSUs vested (USD per share)	18.84
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share)	$ 22.86
Nonvested Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Non-vested units, beginning balance, outstanding (in shares) | shares	175
Granted (in shares) | shares	532
Forfeited (in shares) | shares	(59)
Employee RSUs vested (in shares) | shares	(77)
Non-vested units, ending balance, outstanding (in shares) | shares	571
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share)	$ 34.90
Weighted-average grant date fair value, granted (USD per share)	18.92
Weighted-average grant date fair value, forfeited (USD per share)	27
Weighted average grant date fair value, employee RSUs vested (USD per share)	30.97
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share)	20.57
Weighted-average grant date fair value, director RSUs vested but not issued (USD per share)	$ 31.24
Nonvested Restricted Stock Units [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Number of units, Director RSUs vested but not issued at December 31, 2016 | shares	37

Share-Based Compensation - Su69

Share-Based Compensation - Summary of Nonvested Performance Based Units (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares, nonvested, beginning balance (in shares) | shares	326
Number of shares, granted (in shares) | shares	411
Number of shares, forfeited (in shares) | shares	(90)
Number of shares, vested (in shares) | shares	(130)
Number of shares, nonvested, ending balance (in shares) | shares	517
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share) | $ / shares	$ 26.69
Weighted-average grant date fair value, granted (USD per share) | $ / shares	19.33
Weighted-average grant date fair value, forfeited (USD per share) | $ / shares	29.03
Weighted average grant date fair value, employee RSUs vested (USD per share) | $ / shares	18.84
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share) | $ / shares	$ 22.86

Share-Based Compensation - Su70

Share-Based Compensation - Summary of Nonvested Performance Retention Based Units (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares, nonvested, beginning balance (in shares) | shares	326
Number of shares, granted (in shares) | shares	411
Number of shares, forfeited (in shares) | shares	(90)
Number of shares, vested (in shares) | shares	(130)
Number of shares, nonvested, ending balance (in shares) | shares	517
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share) | $ / shares	$ 26.69
Weighted-average grant date fair value, granted (USD per share) | $ / shares	19.33
Weighted-average grant date fair value, forfeited (USD per share) | $ / shares	29.03
Weighted average grant date fair value, vested (USD per share) | $ / shares	18.84
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share) | $ / shares	$ 22.86
Performance Retention Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares, nonvested, beginning balance (in shares) | shares	213
Number of shares, forfeited (in shares) | shares	(57)
Number of shares, vested (in shares) | shares	(57)
Number of shares, nonvested, ending balance (in shares) | shares	99
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share) | $ / shares	$ 32.82
Weighted-average grant date fair value, forfeited (USD per share) | $ / shares	32.82
Weighted average grant date fair value, vested (USD per share) | $ / shares	32.82
Weighted-average grant date fair value, nonvested weighted-average grant date fair value (USD per share) | $ / shares	$ 32.82

Share-Based Compensation - Empl

Share-Based Compensation - Employee Stock Purchase Plan - Additional Information (Details) - 2016 ESPP [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share purchases offering period	6 months
Percentage of fair market value of options to be purchased	90.00%
Share purchases funded through payroll deduction	10.00%
Share purchases funded through payroll deduction, value | $	$ 25
Stock issued during period to employees, shares, | shares	32,848
Stock issued during period to employees, average price per share | $ / shares	$ 30.50

Commitments and Contingencies -

Commitments and Contingencies - Future Minimum Payments under Non-cancelable Operating Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Contingencies And Commitments [Line Items]
2,017	$ 27,847
2,018	18,248
2,019	16,554
2,020	15,399
2,021	14,283
Thereafter	36,740
Total minimum payments required	129,071
Less: Sublease rentals under non-cancellable leases	(2,566)
Net minimum payments required	126,505
Real Estate [Member]
Contingencies And Commitments [Line Items]
2,017	27,559
2,018	18,006
2,019	16,329
2,020	15,355
2,021	14,283
Thereafter	36,740
Total minimum payments required	128,272
Less: Sublease rentals under non-cancellable leases	(2,566)
Net minimum payments required	125,706
Equipment [Member]
Contingencies And Commitments [Line Items]
2,017	288
2,018	242
2,019	225
2,020	44
2,021	0
Thereafter	0
Total minimum payments required	799
Less: Sublease rentals under non-cancellable leases	0
Net minimum payments required	$ 799

Commitments and Contingencies73

Commitments and Contingencies - Schedule of Rent Expense under Non-cancelable Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Rent expense	$ 38,945	$ 53,912	$ 23,812

Commitments and Contingencies74

Commitments and Contingencies - Additional Information (Details) $ in Millions	Dec. 31, 2016USD ($)
Commitments And Contingencies Disclosure [Abstract]
Outstanding letters of credit	$ 2

Employee Benefits - Additional

Employee Benefits - Additional Information (Details) $ in Thousands	1 Months Ended	10 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)planFund	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of plans offered | plan				2
Number of hedge funds in plan assets | Fund				2
Engility Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution of employer of initial contribution by employee				100.00%	100.00%
Initial matching percentage of employees contribution, employer will match				3.00%	1.50%
Employer contribution matching percentage of additional contribution by employee				50.00%
Employer matching percentage of additional contribution by employee, employer will match				3.00%
Company's contribution under employee savings plan				$ 26,000	$ 4,000	$ 0
TASC Defined Contribution Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution of employer of initial contribution by employee				100.00%
Initial matching percentage of employees contribution, employer will match				3.00%
Employer contribution matching percentage of additional contribution by employee				50.00%
Employer matching percentage of additional contribution by employee, employer will match				2.00%
Company's contribution under employee savings plan		$ 14,000
DRC Deferred Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution of employer of initial contribution by employee				100.00%
Initial matching percentage of employees contribution, employer will match				2.00%
Employer contribution matching percentage of additional contribution by employee				50.00%
Employer matching percentage of additional contribution by employee, employer will match				4.00%
Company's contribution under employee savings plan			$ 3,000
Cash Bonus Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Termination of benefits	$ 3,000
DRC Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Termination of benefits	17,000
Settlement charge	3,000				17,356
Expected employer contributions to fund plan				$ 3,000
Combined projected benefit obligation	78,665	78,665	$ 103,028	$ 77,732	78,665	$ 103,028
Long-term rate of return				8.00%
DRC Defined Benefit Pension Plan [Member] | Minimum [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				45.00%
DRC Defined Benefit Pension Plan [Member] | Minimum [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				30.00%
DRC Defined Benefit Pension Plan [Member] | Minimum [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				0.00%
DRC Defined Benefit Pension Plan [Member] | Minimum [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				2.00%
DRC Defined Benefit Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Cap on Company's stock in fund				3.00%
DRC Defined Benefit Pension Plan [Member] | Maximum [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				65.00%
DRC Defined Benefit Pension Plan [Member] | Maximum [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				50.00%
DRC Defined Benefit Pension Plan [Member] | Maximum [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				20.00%
DRC Defined Benefit Pension Plan [Member] | Maximum [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations				10.00%
DRC Pension Plan and TASC Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Combined projected benefit obligation	$ 97,000	$ 97,000		$ 94,000	$ 97,000

Employee Benefits - Net Periodi

Employee Benefits - Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	10 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
DRC Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost			$ 805
Interest cost on projected benefit obligations		$ 3,589	2,543	$ 3,997
Expected return on plan assets		(5,339)	(3,813)	(5,833)
Net loss amortization			292	231
Settlement loss				3,141
Net periodic benefit income (expense)		$ (1,750)	(173)	1,536
TASC Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost on projected benefit obligations	$ 470		468	$ 470
Immediate recognition of benefit cost due to plan termination	285
Net periodic benefit income (expense)	$ 755		$ 468

Employee Benefits - Obligations

Employee Benefits - Obligations and Funded Status (Details) - USD ($) $ in Thousands	1 Months Ended	10 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Change in plan assets:
Fair value of plan assets at beginning of year				$ 50,130
Fair value of plan assets at end of year	$ 50,130	$ 50,130		48,489	$ 50,130
DRC Pension Plan [Member]
Change in benefit obligation:
Benefit obligation at beginning of year				78,665	103,028
Service cost				805
Acquired benefit obligation					0
Interest cost			$ 3,589	2,543	3,997
Benefits paid				(4,915)	(4,826)
Actuarial loss (gain)				1,506	(5,459)
Administrative expenses paid				(872)	(719)
Settlement	(3,000)				(17,356)
Benefit obligation at end of year	78,665	78,665	103,028	77,732	78,665
Change in plan assets:
Fair value of plan assets at beginning of year				50,130	75,047
Actual return on plan assets				3,286	(2,433)
Employer contributions				860	417
Benefits paid				(4,915)	(4,826)
Administrative expenses paid				(872)	(719)
Settlement					(17,356)
Fair value of plan assets at end of year	50,130	50,130	75,047	48,489	50,130
Unfunded status	(28,535)	(28,535)		(29,243)	(28,535)
TASC Benefit Plan [Member]
Change in benefit obligation:
Benefit obligation at beginning of year				18,146	0
Acquired benefit obligation					20,925
Interest cost		470		468	470
Benefits paid				(286)	(3,330)
Actuarial loss (gain)				(1,873)	81
Settlement					0
Benefit obligation at end of year	18,146	18,146	0	16,455	18,146
Change in plan assets:
Fair value of plan assets at beginning of year				0	0
Actual return on plan assets					0
Employer contributions				286	3,330
Benefits paid				(286)	(3,330)
Settlement					0
Fair value of plan assets at end of year	0	0	$ 0		0
Unfunded status	$ (18,146)	$ (18,146)		$ (16,455)	$ (18,146)

Employee Benefits - Amounts Rec

Employee Benefits - Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
DRC Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities		$ 0
Other long-term liabilities	$ 29,243	28,535
Net amount recognized	29,243	28,535
TASC Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	714	905
Other long-term liabilities	15,741	17,241
Net amount recognized	$ 16,455	$ 18,146

Employee Benefits - Components

Employee Benefits - Components of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	$ 706,133	$ 476,753	$ 443,154
Ending Balance	704,805	706,133	476,753
DRC Pension Plan [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net Loss Amortization	(292)	(291)	0
DRC Pension Plan [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	14,235	14,800	0
Experience Loss (Gain)	2,033	(274)	14,800
Ending Balance	15,976	14,235	14,800
TASC Benefit Plan [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net Loss Amortization		0
TASC Benefit Plan [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance	(204)	0
Experience Loss (Gain)	(1,873)	(204)
Ending Balance	$ (2,077)	$ (204)	$ 0

Employee Benefits - Assumptions

Employee Benefits - Assumptions Used In Calculations (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
DRC Pension Plan [Member]
Used to determine benefit obligations:
Discount rate	3.95%	4.17%
Used to determine net periodic benefit costs:
Discount rate	3.39%	3.94%	4.49%
Expected rate of return on assets	8.00%	8.00%	8.15%
Settlement discount rate		4.17%
Discount rate	3.39%	3.94%	4.49%
TASC Benefit Plan [Member]
Used to determine benefit obligations:
Discount rate	3.54%	3.44%
Used to determine net periodic benefit costs:
Discount rate	2.85%	3.05%
Discount rate	2.85%	3.05%
Cash Bonus Plan [Member]
Used to determine net periodic benefit costs:
Discount rate		0.95%
Discount rate		0.95%

Employee Benefits - Summary of

Employee Benefits - Summary of Fair Value Measurement of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 48,489	$ 50,130
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	301	223
Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,653	3,288
Common Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,340	6,482
Preferred Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		160
Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	86	17,237
Real Estate Investment Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43	613
Exchanged Traded Funds Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,542
Corporate and Foreign Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,101	15,689
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,423	6,438
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25,312	28,003
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	301	223
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		3,288
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Common Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,340	6,482
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Preferred Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		160
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	86	17,237
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Real Estate Investment Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43	613
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Exchanged Traded Funds Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,542
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate and Foreign Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16,754	15,689
Significant Other Observable Inputs (Level 2) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,653	0
Significant Other Observable Inputs (Level 2) [Member] | Common Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) [Member] | Preferred Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) [Member] | Real Estate Investment Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) [Member] | Corporate and Foreign Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,101	15,689
Significant Other Observable Inputs (Level 2) [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,423	6,438	$ 8,326
Significant Unobservable Inputs (Level 3) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Common Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Preferred Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Real Estate Investment Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Corporate and Foreign Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Significant Unobservable Inputs (Level 3) [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 6,423	$ 6,438	$ 6,442

Employee Benefits - Reconciliat

Employee Benefits - Reconciliation of Fair Value Level 3 Inputs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of year	$ 50,130
Fair value of plan assets at end of year	48,489	$ 50,130
Hedge Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of year	6,438
Fair value of plan assets at end of year	6,423	6,438
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of year	6,438	8,326
Actual returns on plan assets related to assets still held at the reporting date	325	(343)
Purchases	104	336
Sales	(444)	(1,881)
Fair value of plan assets at end of year	6,423	6,438
Significant Unobservable Inputs (Level 3) [Member] | Managed Futures [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of year	0	1,884
Actual returns on plan assets related to assets still held at the reporting date		(3)
Purchases		0
Sales		(1,881)
Fair value of plan assets at end of year		0
Significant Unobservable Inputs (Level 3) [Member] | Hedge Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at beginning of year	6,438	6,442
Actual returns on plan assets related to assets still held at the reporting date	325	(340)
Purchases	104	336
Sales	(444)	0
Fair value of plan assets at end of year	$ 6,423	$ 6,438

Employee Benefits - Summary o83

Employee Benefits - Summary of Expected Benefit Payments (Details) $ in Thousands	Dec. 31, 2016USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,017	$ 5,607
2,018	5,885
2,019	6,085
2,020	6,378
2,021	6,583
Five subsequent fiscal years	33,453
DRC Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,017	4,893
2,018	4,938
2,019	4,993
2,020	5,074
2,021	5,063
Five subsequent fiscal years	25,245
TASC Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2,017	714
2,018	947
2,019	1,092
2,020	1,304
2,021	1,520
Five subsequent fiscal years	$ 8,208

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	Aug. 12, 2016	Jan. 31, 2014	Jun. 30, 2016	Apr. 01, 2016	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 09, 2013
Debt Instrument [Line Items]
Gross borrowings from issuance of long-term debt	$ 585,000					$ 1,180,000,000	$ 585,000,000	$ 75,000,000
Gross borrowings from revolving credit facility						137,000,000	157,000,000	482,500,000
Repayment of term loan debt						137,000,000	115,000,000	448,000,000
Average outstanding loan amount						$ 1,147,000,000	$ 1,077,000,000	$ 342,000,000
Interest rate during period						8.07%	8.22%	2.92%
Dynamics Research Corporation [Member]
Debt Instrument [Line Items]
Aggregate cash purchase price		$ 207,000,000
Debt assumed in a business combination		86,000,000
Guarantees [Member]
Debt Instrument [Line Items]
Gross borrowings from issuance of long-term debt								$ 75,000,000
Gross borrowings from revolving credit facility								482,500,000
Repayment of term loan debt								$ 448,000,000
8.875% Senior Notes Due 2024 [Member] | Guarantees [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	Sep. 1, 2024
Senior notes issued	$ 300,000,000
Interest percentage	8.875%
Maturity year	2,024
Guarantor obligation term						The Guarantee of the Notes by each Guarantor is: (i) a general senior obligation of such Guarantor; (ii) equal in right of payment to all existing and future indebtedness of such Guarantor that is not subordinated in right of payment to its Guarantee of the Notes (including its guarantee of the 2016 Credit Facility); (iii) effectively subordinated to any existing and future indebtedness of such Guarantor that is secured with property or assets of such Guarantor to the extent of the value of such property and assets securing such indebtedness (including the 2016 Credit Facility); and (iv) senior in right of payment to any future indebtedness of such Guarantor that is expressly subordinated in right of payment of the Notes
Interest payments term						Interest on the Notes is payable on March 1 and September 1 of each year, beginning on March 1, 2017, with the Notes maturing on September 1, 2024
Redemption date	Sep. 1, 2019
Redemption price percentages of the principal amount	100.00%
2016 Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility	$ 1,045,000,000
Commitment fee percentage	0.50%
Debt instrument prepayment premium percentage	1.00%
Percentage of annual excess cash flow for prepayment of loan	50.00%
Prepayment of outstanding term loan as percentage of net cash proceeds of non-ordinary course asset sales or other non-ordinary course dispositions of property or certain casualty events	100.00%
Required investment period of net cash proceeds of non-ordinary course asset sales or other non-ordinary course dispositions of property or certain casualty events	450 days
Prepayment of outstanding term loan percentage of net cash proceeds from issuance of debt except twenty sixteen credit facility	100.00%
Secured debt To EBITDA ratio	6.125%
Consolidated net leverage ratio						3.73%
Current borrowing capacity						$ 163,000,000
Debt issuances costs						11,000,000
2016 Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit, amount outstanding						$ 2,000,000
2016 Credit Facility [Member] | Company’s Net First Lien Secured Leverage Ratio is not Greater than 3.50:1.00 [Member]
Debt Instrument [Line Items]
Percentage of annual excess cash flow for prepayment of loan	25.00%
2016 Credit Facility [Member] | Company’s Net First Lien Secured Leverage Ratio is not Greater than 3.00:1.00 [Member]
Debt Instrument [Line Items]
Percentage of annual excess cash flow for prepayment of loan	0.00%
2016 Credit Facility [Member] | Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
2016 Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
2016 Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Additional commitments aggregate principal amount	$ 150,000,000
First lien secured leverage ratio	4.00%
Commitment to reinvest net cash proceeds of non-ordinary course asset sales or other non-ordinary course dispositions of property or certain casualty events period	630 days
2016 Credit Facility [Member] | Maximum [Member] | Company’s Net First Lien Secured Leverage Ratio is not Greater than 3.50:1.00 [Member]
Debt Instrument [Line Items]
Net first lien secured leverage ratio, option one	3.50%
2016 Credit Facility [Member] | Maximum [Member] | Company’s Net First Lien Secured Leverage Ratio is not Greater than 3.00:1.00 [Member]
Debt Instrument [Line Items]
Net first lien secured leverage ratio, option two	3.00%
2016 Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Commitment to reinvest net cash proceeds of non-ordinary course asset sales or other non-ordinary course dispositions of property or certain casualty events period	450 days
2016 Credit Facility [Member] | Term B1 Loan [Member]
Debt Instrument [Line Items]
Total credit facility	$ 200,000,000
Debt instrument maturity date						Aug. 12, 2020
Quarterly payment of term loan, percentage						2.50%
2016 Credit Facility [Member] | Term B1 Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Variable rate floor	0.00%
2016 Credit Facility [Member] | Term B1 Loan [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	3.25%
Variable rate floor	0.00%
2016 Credit Facility [Member] | Term B2 Loan [Member]
Debt Instrument [Line Items]
Total credit facility	$ 680,000,000
Debt instrument maturity date						Aug. 12, 2023
Quarterly payment of term loan, percentage						0.25%
Prepayment of term loan debt					$ 50,000
2016 Credit Facility [Member] | Term B2 Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Variable rate floor	1.00%
2016 Credit Facility [Member] | Term B2 Loan [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	3.75%
Variable rate floor	1.00%
2016 Credit Facility [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility	$ 165,000,000
Debt instrument maturity date						Aug. 12, 2021
2016 Credit Facility [Member] | Senior Secured Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Variable rate floor	0.00%
2016 Credit Facility [Member] | Senior Secured Revolving Credit Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Variable rate floor	0.00%
2016 Credit Facility [Member] | Subfacilities for Issuance Letters of Credit [Member]
Debt Instrument [Line Items]
Total credit facility	$ 35,000,000
2016 Credit Facility [Member] | Swingline Commitment for Swingline Borrowings [Member]
Debt Instrument [Line Items]
Total credit facility	$ 35,000,000
Indenture [Member] | 8.875% Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Redemption price percentages of the principal amount	108.875%
Debt instrument, redemption period	120 days
Debt instrument redemption price to be offered as percentage of face amount of notes	101.00%
Indenture [Member] | 8.875% Senior Notes Due 2024 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument percentage redeemable with cash proceeds of equity offerings	35.00%
Indenture [Member] | 8.875% Senior Notes Due 2024 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Percentage of aggregate principal amount of notes that should be outstanding after redemption	60.00%
Percentage of aggregate principal amount of Notes holders should own to declare Notes immediately payable if default occurs	30.00%
Registration Rights Agreement [Member]
Debt Instrument [Line Items]
Interest percentage	0.25%
Increase in interest rate	0.25%
Debt instrument description						which rate will be increased by an additional 0.25% per annum for each subsequent 90-day period that such additional interest continues to accrue, provided that the rate at which such additional interest accrues may in no event exceed 1.0%
Registration Rights Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Rate at which additional interest accrues	1.00%
Credit Facilities 2015 [Member]
Debt Instrument [Line Items]
Early termination penalty						$ 10,000,000
Credit Facilities 2015 [Member] | Interest Expense [Member]
Debt Instrument [Line Items]
Debt issuance costs expensed						5,000,000
Credit Facilities 2015 [Member] | Second Lien Term Loan [Member]
Debt Instrument [Line Items]
Extinguishment of debt				$ 10,000		$ 11,000
Credit Facilities 2015 [Member] | Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Credit Facilities 2015 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Variable rate floor	1.00%
Credit Facilities 2015 [Member] | Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility	$ 115,000,000
Credit Facilities 2015 [Member] | Senior Secured Term Loan [Member] | First Lien Term Facility [Member]
Debt Instrument [Line Items]
Total credit facility	830,000,000
Credit Facilities 2015 [Member] | Senior Secured Term Loan [Member] | Second Lien Term Facility [Member]
Debt Instrument [Line Items]
Total credit facility	400,000,000
Original First Lien Term Facility [Member] | Senior Secured Term Loan Facility [Member]
Debt Instrument [Line Items]
Total credit facility	395,000,000
First Lien Credit Agreement and Second Lien Credit Agreement [Member] | Incremental Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility	50,000,000
Original Second Lien Term Facility [Member] | Incremental Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility	250,000,000
Incremental First Lien Term Facility [Member] | Senior Secured Term Loan Facility [Member]
Debt Instrument [Line Items]
Total credit facility	435,000,000
Additional Senior Secured First Lien Revolving Credit Capacity [Member] | Incremental Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility	65,000,000
Incremental Second Lien Term Facility [Member] | Senior Secured Term Loan Facility [Member]
Debt Instrument [Line Items]
Total credit facility	$ 150,000,000
First Lien Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	6.00%
First Lien Credit Agreement [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	5.00%
Second Lien Credit Agreement [Member]
Debt Instrument [Line Items]
Interest percentage	12.00%
2013 Credit Facility [Member]
Debt Instrument [Line Items]
Basis spread on variable rate						0.50%
Letter of credit sublimit									$ 50,000,000
Swing line loan sublimit									25,000,000
Additional commitments									150,000,000
Debt issuances costs							$ 5,000,000
2013 Credit Facility [Member] | Interest Expense [Member]
Debt Instrument [Line Items]
Debt issuance costs expensed							$ 1,000,000
2013 Credit Facility [Member] | Senior Secured Term Loan Facility [Member]
Debt Instrument [Line Items]
Total credit facility									200,000,000
2013 Credit Facility [Member] | Incremental Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility									$ 250,000,000
2013 Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate						1.00%
2013 Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
LIBOR margin						3.25%
Base rate margin						2.25%
2013 Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
LIBOR margin						2.25%
Base rate margin						1.25%
2013 Credit Facility Amended [Member]
Debt Instrument [Line Items]
Gross borrowings from issuance of long-term debt		75,000,000
Proceeds from issuance of debt		150,000,000
Gross borrowings from revolving credit facility		$ 75,000,000
2015 and 2016 Credit Facilities [Member]
Debt Instrument [Line Items]
Repayment of term loan debt						$ 91,000
Term Loan [Member]
Debt Instrument [Line Items]
Prepayment of term loan debt			$ 20,000

Debt - Schedule of Redemption P

Debt - Schedule of Redemption Price as Percentage of Principal Amount (Details)	Aug. 12, 2016
2019 [Member]
Debt Instrument Redemption [Line Items]
Percentage	104.438%
2020 [Member]
Debt Instrument Redemption [Line Items]
Percentage	102.219%
2021 and Thereafter [Member]
Debt Instrument Redemption [Line Items]
Percentage	100.00%

Debt - Schedule of Composition

Debt - Schedule of Composition of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total debt	$ 1,123,761	$ 1,160,315
Less: current portion of long-term debt	(26,947)	(8,447)
Less: unamortized original issue discount costs and financing fees	(56,821)	(57,839)
Long-term debt	1,039,993	1,094,029
Notes [Member]
Debt Instrument [Line Items]
Total debt	300,000
Term Loan [Member]
Debt Instrument [Line Items]
Total debt	823,300	1,159,725
Other [Member]
Debt Instrument [Line Items]
Total debt	$ 461	$ 590

Debt - Summary of Debt Minimum

Debt - Summary of Debt Minimum Payments on Term Credit Facility (Details) $ in Thousands	Dec. 31, 2016USD ($)
Debt Disclosure [Abstract]
2,017	$ 26,800
2,018	26,800
2,019	26,800
2,020	141,800
2,021	6,800
Thereafter	894,300
Total minimum payments required	$ 1,123,300

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, expiration date	Dec. 31, 2016
Interest Rate Swap Effective December 31, 2015 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, combined notional amount	$ 200
Interest Rate Swap Agreements [Member] | Credit Facility 2015 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit facility termination charge	2
Credit facility termination loss	$ 1

Fair Value Measurements - Other

Fair Value Measurements - Other Terms of Instruments (Details) - Interest Rate Swap [Member]	Dec. 31, 2016
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, fixed interest rate	3.09%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, fixed interest rate	3.18%
London Interbank Offered Rate (LIBOR) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, swaption interest rate	1.25%

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Assets and Liabilities Measured on a Recurring Basis (Details) $ in Thousands	Dec. 31, 2015USD ($)
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap liability	$ 3,590

Restructuring and Integration91

Restructuring and Integration Costs - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost And Reserve [Line Items]
Restructuring costs	$ 12	$ 21
Dynamics Research Corporation [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring costs			$ 1

Restructuring and Integration92

Restructuring and Integration Costs - Summary of Restructuring and Integration Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 13,477	$ 6,404	$ 7,870
Additions	11,543	21,090	1,134
Cash payments	(18,763)	(14,017)	(2,600)
Other adjustments	(2,429)
Ending Balance	3,828	13,477	6,404
Other Current Liabilities [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	9,398
Ending Balance		9,398
Other Liabilities [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	4,079
Ending Balance		4,079
Current Liabilities [Member]
Restructuring Reserve [Roll Forward]
Ending Balance	3,828
Severance and Related Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	4,006	368	337
Additions	9,357	14,614	1,134
Cash payments	(12,059)	(10,976)	(1,103)
Other adjustments	0
Ending Balance	1,304	4,006	368
Severance and Related Costs [Member] | Other Current Liabilities [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	4,006
Ending Balance		4,006
Severance and Related Costs [Member] | Other Liabilities [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	0
Ending Balance		0
Severance and Related Costs [Member] | Current Liabilities [Member]
Restructuring Reserve [Roll Forward]
Ending Balance	1,304
Other Restructuring Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	9,471	6,036	7,533
Additions	2,186	6,476	0
Cash payments	(6,704)	(3,041)	(1,497)
Other adjustments	(2,429)
Ending Balance	2,524	9,471	$ 6,036
Other Restructuring Costs [Member] | Other Current Liabilities [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	5,392
Ending Balance		5,392
Other Restructuring Costs [Member] | Other Liabilities [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	4,079
Ending Balance		$ 4,079
Other Restructuring Costs [Member] | Current Liabilities [Member]
Restructuring Reserve [Roll Forward]
Ending Balance	$ 2,524

Separate Financial Informatio93

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Additional Information (Details)	Dec. 31, 2016
Guarantees [Member]
Guarantee Obligations [Line Items]
Percentage of voting stock outstanding in subsidiary guarantors	100.00%

Separate Financial Informatio94

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Supplemental Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 48,236		$ 30,022	$ 7,123	$ 29,003
Receivables, net	334,248		381,760
Prepaid income taxes	5,430		5,003
Assets held for sale, current	20,242	$ 2,000
Other current assets	24,974		24,655
Total current assets	433,130		441,440
Property, plant and equipment, net	46,547		44,120
Goodwill	1,078,454		1,093,178	644,554
Identifiable intangible assets, net	393,891		436,627
Deferred tax assets	232,283		235,397
Assets held for sale	11,962
Other assets	2,292		3,211
Total assets	2,198,559		2,253,973
Current liabilities:
Current portion of long-term debt	26,947		8,447
Accounts payable, trade	43,943		54,345
Accrued employment costs	98,860		81,711
Accrued expenses	76,870		82,765
Advance payments and billings in excess of costs incurred	33,259		49,205
Deferred income taxes, current and income tax liabilities	209		695
Liabilities held for sale, current	4,341
Other current liabilities	36,410		36,293
Total current liabilities	320,839		313,461
Long-term debt	1,039,993		1,094,029
Income tax liabilities	64,852		68,000
Liabilities held for sale	1,084
Other liabilities	66,986		72,350
Total liabilities	1,493,754		1,547,840
Shareholders' equity	704,805		706,133	476,753	443,154
Total liabilities and equity	2,198,559		2,253,973
Engility Holdings, Inc. [Member]
Current assets:
Investment in subsidiaries	704,805		706,133
Total assets	704,805		706,133
Current liabilities:
Shareholders' equity	704,805		706,133
Total liabilities and equity	704,805		706,133
Engility Corporation [Member]
Current assets:
Cash and cash equivalents	31,124		18,313
Receivables, net	280,709		314,917
Intercompany receivables	83,739		4,983
Prepaid income taxes	5,211		4,811
Assets held for sale, current	2,332
Other current assets	22,226		22,731
Total current assets	425,341		365,755
Property, plant and equipment, net	40,071		37,415
Goodwill	1,020,027		1,034,751
Identifiable intangible assets, net	359,465		399,570
Deferred tax assets	213,296		210,727
Investment in subsidiaries	89,543		141,630
Other assets	2,292		2,229
Total assets	2,150,035		2,192,077
Current liabilities:
Current portion of long-term debt	26,947		8,447
Accounts payable, trade	43,848		50,468
Intercompany payable	758
Accrued employment costs	87,199		64,463
Accrued expenses	76,520		76,606
Advance payments and billings in excess of costs incurred	33,259		48,876
Deferred income taxes, current and income tax liabilities			447
Other current liabilities	34,398		34,590
Total current liabilities	302,929		283,897
Long-term debt	1,039,993		1,094,029
Income tax liabilities	64,852		68,000
Other liabilities	37,456		40,018
Total liabilities	1,445,230		1,485,944
Shareholders' equity	704,805		706,133
Total liabilities and equity	2,150,035		2,192,077
Subsidiary Guarantors [Member]
Current assets:
Cash and cash equivalents	385		29	3,127	17,295
Receivables, net	34,655		44,665
Assets held for sale, current	17,910
Other current assets	506		3
Total current assets	53,456		44,697
Property, plant and equipment, net	6,345		6,344
Goodwill	58,427		58,427
Identifiable intangible assets, net	34,426		37,057
Deferred tax assets	18,987		24,670
Assets held for sale	11,962
Investment in subsidiaries	29,248		23,401
Other assets			982
Total assets	212,851		195,578
Current liabilities:
Accounts payable, trade	37		3,628
Intercompany payable	83,739		2,030
Accrued employment costs	4,530		9,789
Accrued expenses			5,809
Advance payments and billings in excess of costs incurred			329
Liabilities held for sale, current	4,341
Other current liabilities	47		31
Total current liabilities	92,694		21,616
Liabilities held for sale	1,084
Other liabilities	29,530		32,332
Total liabilities	123,308		53,948
Shareholders' equity	89,543		141,630
Total liabilities and equity	212,851		195,578
Subsidiary Non-guarantors [Member]
Current assets:
Cash and cash equivalents	16,727		11,680	$ 3,996	$ 11,708
Receivables, net	18,884		22,178
Intercompany receivables	758
Prepaid income taxes	219		192
Other current assets	2,242		1,921
Total current assets	38,830		35,971
Property, plant and equipment, net	131		361
Total assets	38,961		36,332
Current liabilities:
Accounts payable, trade	58		249
Intercompany payable			2,953
Accrued employment costs	7,131		7,459
Accrued expenses	350		350
Deferred income taxes, current and income tax liabilities	230		248
Other current liabilities	1,944		1,672
Total current liabilities	9,713		12,931
Total liabilities	9,713		12,931
Shareholders' equity	29,248		23,401
Total liabilities and equity	38,961		36,332
Consolidating Adjustments [Member]
Current assets:
Intercompany receivables	(84,497)		(4,983)
Total current assets	(84,497)		(4,983)
Investment in subsidiaries	(823,596)		(871,164)
Total assets	(908,093)		(876,147)
Current liabilities:
Intercompany payable	(84,497)		(4,983)
Deferred income taxes, current and income tax liabilities	(21)
Other current liabilities	21
Total current liabilities	(84,497)		(4,983)
Total liabilities	(84,497)		(4,983)
Shareholders' equity	(823,596)		(871,164)
Total liabilities and equity	$ (908,093)		$ (876,147)

Separate Financial Informatio95

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Supplemental Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($)	Nov. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue			$ 2,076,423,000	$ 2,085,623,000	$ 1,367,091,000
Costs and expenses
Cost of revenue			1,777,844,000	1,779,709,000	1,169,281,000
Selling, general and administrative expenses			166,238,000	203,262,000	114,890,000
Goodwill impairment	$ 0	$ 292,000,000	9,875,000	292,100,000
Total costs and expenses			1,953,957,000	2,275,071,000	1,284,171,000
Operating income (loss)			122,466,000	(189,448,000)	82,920,000
Interest expense, net			131,185,000	110,143,000	12,799,000
Other income (expenses), net			(80,000)	1,285,000	526,000
Income (loss) before income taxes			(8,799,000)	(298,306,000)	70,647,000
Provision (benefit) for income taxes			(2,730,000)	(68,067,000)	30,637,000
Net income (loss)			(6,069,000)	(230,239,000)	40,010,000
Less: Net income attributable to non-controlling interest			4,738,000	5,113,000	4,587,000
Net income (loss) attributable to Engility			(10,807,000)	(235,352,000)	35,423,000
Net income (loss)			(6,069,000)	(230,239,000)	40,010,000
Other comprehensive income			2,364,000	1,789,000	(9,018,000)
Comprehensive income (loss)			(3,705,000)	(228,450,000)	30,992,000
Less: Net income attributable to non-controlling interest			4,738,000	5,113,000	4,587,000
Comprehensive income (loss) attributable to Engility			(8,443,000)	(233,563,000)	26,405,000
Engility Holdings, Inc. [Member]
Costs and expenses
Income in equity investments in subsidiaries			(10,807,000)	(235,352,000)	35,423,000
Income (loss) before income taxes			(10,807,000)	(235,352,000)	35,423,000
Net income (loss)			(10,807,000)	(235,352,000)	35,423,000
Net income (loss) attributable to Engility			(10,807,000)	(235,352,000)	35,423,000
Net income (loss)			(10,807,000)	(235,352,000)	35,423,000
Comprehensive income (loss)			(10,807,000)	(235,352,000)	35,423,000
Comprehensive income (loss) attributable to Engility			(10,807,000)	(235,352,000)	35,423,000
Engility Corporation [Member]
Revenue			1,730,876,000	1,622,029,000
Costs and expenses
Cost of revenue			1,423,013,000	1,384,997,000
Selling, general and administrative expenses			132,476,000	163,019,000
Goodwill impairment			9,875,000	183,577,000
Total costs and expenses			1,565,364,000	1,731,593,000
Operating income (loss)			165,512,000	(109,564,000)
Interest expense, net			131,185,000	110,148,000
Other income (expenses), net			135,000	1,289,000
Income in equity investments in subsidiaries			(52,259,000)	(60,844,000)
Income (loss) before income taxes			(17,797,000)	(279,267,000)
Provision (benefit) for income taxes			(6,990,000)	(43,915,000)
Net income (loss)			(10,807,000)	(235,352,000)
Net income (loss) attributable to Engility			(10,807,000)	(235,352,000)
Net income (loss)			(10,807,000)	(235,352,000)
Other comprehensive income			2,191,000	1,428,000
Comprehensive income (loss)			(8,616,000)	(233,924,000)
Comprehensive income (loss) attributable to Engility			(8,616,000)	(233,924,000)
Subsidiary Guarantors [Member]
Revenue			191,381,000	325,926,000	1,228,538,000
Costs and expenses
Cost of revenue			213,650,000	270,790,000	1,040,552,000
Selling, general and administrative expenses			30,703,000	36,540,000	113,216,000
Goodwill impairment				108,523,000
Total costs and expenses			244,353,000	415,853,000	1,153,768,000
Operating income (loss)			(52,972,000)	(89,927,000)	74,770,000
Interest expense, net					12,803,000
Other income (expenses), net			(1,000)	(4,000)	526,000
Income in equity investments in subsidiaries			4,974,000	4,935,000	3,567,000
Income (loss) before income taxes			(47,999,000)	(84,996,000)	66,060,000
Provision (benefit) for income taxes			4,260,000	(24,152,000)	30,637,000
Net income (loss)			(52,259,000)	(60,844,000)	35,423,000
Net income (loss) attributable to Engility			(52,259,000)	(60,844,000)	35,423,000
Net income (loss)			(52,259,000)	(60,844,000)	35,423,000
Other comprehensive income			173,000	361,000	(9,018,000)
Comprehensive income (loss)			(52,086,000)	(60,483,000)	26,405,000
Comprehensive income (loss) attributable to Engility			(52,086,000)	(60,483,000)	26,405,000
Subsidiary Non-guarantors [Member]
Revenue			154,166,000	156,704,000	148,243,000
Costs and expenses
Cost of revenue			141,181,000	142,958,000	138,419,000
Selling, general and administrative expenses			3,059,000	3,703,000	1,674,000
Total costs and expenses			144,240,000	146,661,000	140,093,000
Operating income (loss)			9,926,000	10,043,000	8,150,000
Interest expense, net				(5,000)	(4,000)
Other income (expenses), net			(214,000)
Income (loss) before income taxes			9,712,000	10,048,000	8,154,000
Net income (loss)			9,712,000	10,048,000	8,154,000
Less: Net income attributable to non-controlling interest			4,738,000	5,113,000	4,587,000
Net income (loss) attributable to Engility			4,974,000	4,935,000	3,567,000
Net income (loss)			9,712,000	10,048,000	8,154,000
Comprehensive income (loss)			9,712,000	10,048,000	8,154,000
Less: Net income attributable to non-controlling interest			4,738,000	5,113,000	4,587,000
Comprehensive income (loss) attributable to Engility			4,974,000	4,935,000	3,567,000
Consolidating Adjustments [Member]
Revenue				(19,036,000)	(9,690,000)
Costs and expenses
Cost of revenue				(19,036,000)	(9,690,000)
Total costs and expenses				(19,036,000)	(9,690,000)
Income in equity investments in subsidiaries			58,092,000	291,261,000	(38,990,000)
Income (loss) before income taxes			58,092,000	291,261,000	(38,990,000)
Net income (loss)			58,092,000	291,261,000	(38,990,000)
Net income (loss) attributable to Engility			58,092,000	291,261,000	(38,990,000)
Net income (loss)			58,092,000	291,261,000	(38,990,000)
Comprehensive income (loss)			58,092,000	291,261,000	(38,990,000)
Comprehensive income (loss) attributable to Engility			$ 58,092,000	$ 291,261,000	$ (38,990,000)

Separate Financial Informatio96

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Supplemental Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	Aug. 12, 2016	Feb. 26, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net cash provided by operating activities			$ 94,405	$ 48,418	$ 102,359
Investing activities:
Acquisitions, net of cash acquired				25,478	(207,250)
Capital expenditures			(21,446)	(19,610)	(5,436)
Net cash (used in) provided by investing activities			(21,446)	5,868	(212,686)
Financing activities:
Gross borrowings from issuance of long-term debt	$ 585		1,180,000	585,000	75,000
Repayment of long-term debt			(1,215,754)	(403,674)	(13,750)
Gross borrowings from revolving credit facility			137,000	157,000	482,500
Repayments of revolving credit facility			(137,000)	(115,000)	(448,000)
Debt issuance costs			(9,988)	(42,425)	(1,131)
Equity issuance costs				(2,590)
Proceeds from share-based payment arrangements			214	279	1,479
Payment of employee withholding taxes on share-based compensation			(1,779)	(8,021)	(2,371)
Excess tax deduction on share-based compensation				5,530	1,707
Dividends paid		$ (204,000)	(1,709)	(204,304)
Distributions to non-controlling interest member			(3,865)	(3,182)	(6,987)
Net cash (used in) provided by financing activities			(52,881)	(31,387)	88,447
Change in cash from assets held from sale			(1,864)
Net change in cash and cash equivalents			18,214	22,899	(21,880)
Cash and cash equivalents, beginning of period			30,022	7,123	29,003
Cash and cash equivalents, end of period			48,236	30,022	7,123
Engility Holdings, Inc. [Member]
Financing activities:
Equity issuance costs				(2,590)
Proceeds from share-based payment arrangements			214	279	1,479
Payment of employee withholding taxes on share-based compensation			(1,779)	(8,021)	(2,371)
Excess tax deduction on share-based compensation				5,530	1,707
Dividends paid			(1,709)	(204,304)
Due (to) from subsidiaries			3,274	209,106	(815)
Engility Corporation [Member]
Operating activities:
Net cash provided by operating activities			163,136	45,633
Investing activities:
Acquisitions, net of cash acquired				25,478
Capital expenditures			(21,446)	(19,610)
Net cash (used in) provided by investing activities			(21,446)	5,868
Financing activities:
Gross borrowings from issuance of long-term debt			1,180,000	585,000
Repayment of long-term debt			(1,215,754)	(403,674)
Gross borrowings from revolving credit facility			137,000	157,000
Repayments of revolving credit facility			(137,000)	(115,000)
Debt issuance costs			(9,988)	(42,425)
Due (to) from subsidiaries			(81,273)	(214,089)
Net cash (used in) provided by financing activities			(127,015)	(33,188)
Change in cash from assets held from sale			(1,864)
Net change in cash and cash equivalents			12,811	18,313
Cash and cash equivalents, beginning of period			18,313
Cash and cash equivalents, end of period			31,124	18,313
Subsidiary Guarantors [Member]
Operating activities:
Net cash provided by operating activities			(81,354)	(10,754)	104,849
Investing activities:
Acquisitions, net of cash acquired					(207,250)
Capital expenditures					(5,436)
Net cash (used in) provided by investing activities					(212,686)
Financing activities:
Gross borrowings from issuance of long-term debt					75,000
Repayment of long-term debt					(13,750)
Gross borrowings from revolving credit facility					482,500
Repayments of revolving credit facility					(448,000)
Debt issuance costs					(1,131)
Due (to) from subsidiaries			81,710	7,656	(950)
Net cash (used in) provided by financing activities			81,710	7,656	93,669
Net change in cash and cash equivalents			356	(3,098)	(14,168)
Cash and cash equivalents, beginning of period			29	3,127	17,295
Cash and cash equivalents, end of period			385	29	3,127
Subsidiary Non-guarantors [Member]
Operating activities:
Net cash provided by operating activities			12,623	13,539	(2,490)
Financing activities:
Distributions to non-controlling interest member			(3,865)	(3,182)	(6,987)
Due (to) from subsidiaries			(3,711)	(2,673)	1,765
Net cash (used in) provided by financing activities			(7,576)	(5,855)	(5,222)
Net change in cash and cash equivalents			5,047	7,684	(7,712)
Cash and cash equivalents, beginning of period			11,680	3,996	11,708
Cash and cash equivalents, end of period			$ 16,727	$ 11,680	$ 3,996

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($)	Feb. 13, 2017	Jan. 06, 2017	Aug. 12, 2016	Dec. 31, 2016	Mar. 31, 2017
2016 Credit Facility [Member]
Subsequent Event [Line Items]
Total credit facility			$ 1,045,000,000
Amendment [Member]
Subsequent Event [Line Items]
Expected Interest expense, after fees and expenses in fiscal year 2017				$ 5,000,000
Term B1 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Total credit facility			200,000,000
Term B2 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Total credit facility			$ 680,000,000
Morgan Stanley [Member] | Amendment [Member]
Subsequent Event [Line Items]
Borrowing capacity, description				The Amendment was accomplished by (i) the Borrower obtaining new term B1 loan commitments (“New Term B1 Loans”) to reprice the Existing Term B1 Loans and Morgan Stanley making additional New Term B1 Loans to the Borrower in a principal amount equal to $195.0 million minus the principal amount of any Existing Term B1 Loans outstanding on the Amendment Effective Date that were converted into New Term B1 Loans on the Amendment Effective Date, and (ii) the Borrower obtaining new term B2 loan commitments (“New Term B2 Loans”) to reprice the Existing Term B2 Loans and Morgan Stanley making additional New Term B2 Loans to the Borrower in a principal amount equal to $608.0 million minus the principal amount of any Existing Term B2 Loans outstanding on the Amendment Effective Date that were converted into New Term B2 Loans on the Amendment Effective Date. The proceeds of the New Term B1 Loans and New Term B2 Loans, respectively, will be applied to repay in full the Existing Term B1 Loans and Existing Term B2 Loans, respectively, outstanding as of the Amendment Effective Date.
Base Rate Loans [Member] | Term B1 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate			3.25%
Base Rate Loans [Member] | Term B2 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate			3.75%
Eurocurrency Loans [Member] | Term B1 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate			4.25%
Eurocurrency Loans [Member] | Term B2 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate			4.75%
Subsequent Event [Member] | Morgan Stanley [Member] | New Term B1 Loans [Member] | Amendment [Member]
Subsequent Event [Line Items]
Additional borrowing capacity	$ 195,000,000
Subsequent Event [Member] | Morgan Stanley [Member] | New Term B2 Loans [Member] | Amendment [Member]
Subsequent Event [Line Items]
Additional borrowing capacity	$ 608,000,000
Subsequent Event [Member] | Base Rate Loans [Member] | Term B1 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	2.25%
Subsequent Event [Member] | Base Rate Loans [Member] | Term B2 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	2.75%
Subsequent Event [Member] | Eurocurrency Loans [Member] | Term B1 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	3.25%
Subsequent Event [Member] | Eurocurrency Loans [Member] | Term B2 Loan [Member] | 2016 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	3.75%
International Resources Group Ltd. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Purchase price		$ 24,000,000
International Resources Group Ltd. [Member] | Scenario, Forecast [Member]
Subsequent Event [Line Items]
Indemnity escrow					$ 2,000,000