Engility 10-Q 31 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 28, 2018	Oct. 29, 2018
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-Q
Document Period End Date	Sep. 28, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	EGL
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		36,968,909
Entity Small Business	false
Entity Emerging Growth Company	false

Unaudited Consolidated Balance

Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 28, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 41,699	$ 41,890
Accounts receivables, net	75,905	108,100
Unbilled receivables	255,459	222,994
Other current assets	18,590	19,681
Total current assets	391,653	392,665
Property, plant and equipment, net	49,492	44,006
Goodwill	1,071,371	1,071,371
Identifiable intangible assets, net	337,047	361,410
Deferred tax assets	109,464	150,535
Other assets	5,786	6,021
Total assets	1,964,813	2,026,008
Current liabilities:
Current portion of long-term debt	25,260	26,947
Accounts payable, trade	44,900	52,954
Accrued employment costs	99,304	77,545
Accrued expenses	79,766	74,856
Advance payments and billings in excess of costs incurred	26,261	30,380
Income tax liabilities	352	548
Other current liabilities	16,257	26,688
Total current liabilities	292,100	289,918
Long-term debt	871,857	938,687
Income tax liabilities	33,080	62,219
Other liabilities	59,987	59,079
Total liabilities	1,257,024	1,349,903
Commitments and contingencies (Note 10)
Equity:
Preferred stock, par value $0.01 per share, 25,000 shares authorized, none issued or outstanding as of September 28, 2018 or December 31, 2017
Common stock, par value $0.01 per share, 175,000 shares authorized, 36,969 and 36,822 shares issued and outstanding as of September 28, 2018 and December 31, 2017, respectively	370	368
Additional paid-in capital	1,252,006	1,244,940
Accumulated deficit	(552,151)	(576,019)
Accumulated other comprehensive loss	(1,693)	(3,805)
Total equity attributable to Engility	698,532	665,484
Non-controlling interest	9,257	10,621
Total equity	707,789	676,105
Total liabilities and equity	$ 1,964,813	$ 2,026,008

Unaudited Consolidated Balanc_2

Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 28, 2018	Dec. 31, 2017
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)	36,969,000	36,822,000
Common stock, shares outstanding (shares)	36,969,000	36,822,000

Unaudited Consolidated Statemen

Unaudited Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Income Statement [Abstract]
Revenue	$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Costs and expenses
Cost of revenue	400,474	417,581	1,225,662	1,255,603
Selling, general and administrative expenses	43,925	33,419	120,811	107,636
Total costs and expenses	444,399	451,000	1,346,473	1,363,239
Operating income	26,808	36,144	89,808	103,791
Interest expense, net	16,981	19,739	53,520	59,189
Other income, net	(191)	(62)	(441)	(121)
Income before provision for income taxes	10,018	16,467	36,729	44,723
Provision for income taxes	4,601	5,611	10,968	16,671
Net income	5,417	10,856	25,761	28,052
Less: Net income attributable to non-controlling interest	1,135	1,051	3,063	3,683
Net income attributable to Engility	$ 4,282	$ 9,805	$ 22,698	$ 24,369
Earnings per share attributable to Engility
Basic	$ 0.12	$ 0.27	$ 0.61	$ 0.66
Diluted	$ 0.11	$ 0.26	$ 0.60	$ 0.65
Weighted average number of shares outstanding
Basic	36,968	36,809	36,928	36,831
Diluted	37,782	37,348	37,737	37,354

Unaudited Consolidated Statem_2

Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 5,417	$ 10,856	$ 25,761	$ 28,052
Other comprehensive income (loss), net of tax:
Pension liability adjustment, net of tax benefit of $23 and $38 for the three and nine months ended September 28, 2018, respectively, and $7 and $84 for for the three and nine months ended September 29, 2017, respectively	(64)	(11)	(108)	(103)
Unrealized gain (loss) on derivative instruments, net of tax expense of $220 and $1,076 for the three and nine months ended September 28, 2018, respectively, and net of tax benefit of $28 and $343 for the three and nine months ended September 29, 2017, respectively	625	(44)	3,056	(536)
Other comprehensive income (loss), net of tax	561	(55)	2,948	(639)
Comprehensive income	5,978	10,801	28,709	27,413
Less: Net income attributable to non-controlling interest	1,135	1,051	3,063	3,683
Comprehensive income attributable to Engility	$ 4,843	$ 9,750	$ 25,646	$ 23,730

Unaudited Consolidated Statem_3

Unaudited Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Statement Of Income And Comprehensive Income [Abstract]
Pension liability adjustment, tax benefit	$ 23	$ 7	$ 38	$ 84
Unrealized gain on derivative instruments, tax expense	$ 220	$ 28	$ 1,076	$ 343

Unaudited Consolidated Statem_4

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017
Operating activities:
Net income	$ 25,761	$ 28,052
Share-based compensation	9,111	6,052
Depreciation and amortization	32,460	33,172
Loss (gain) on sale of property, plant and equipment	69	(306)
Loss on extinguishment of debt	253	432
Amortization of bank debt fees	6,389	6,484
Deferred income taxes	39,810	17,096
Excess tax deduction on share-based compensation	106	(191)
Changes in operating assets and liabilities:
Receivables	5,213	(7,465)
Other assets	31	7,894
Accounts payable, trade	(9,310)	5,332
Accrued employment costs	21,759	(2,133)
Accrued expenses	4,023	5,093
Advance payments and billings in excess of costs incurred	(4,119)	(1,354)
Other liabilities	(36,811)	(19,403)
Net cash provided by operating activities	94,745	78,755
Investing activities:
Proceeds (payments) from sale of business, net of amount placed in escrow	(1,900)	22,349
Proceeds from sale of property, plant and equipment		2,902
Capital expenditures	(11,404)	(5,810)
Net cash provided by (used in) investing activities	(13,304)	19,441
Financing activities:
Repayment of long-term debt	(75,115)	(86,410)
Gross borrowings from revolving credit facility	167,000	270,000
Gross repayments of revolving credit facility	(167,000)	(270,000)
Debt issuance costs	(45)
Payment of employee withholding taxes on share-based compensation	(2,045)	(1,501)
Dividends paid		(407)
Distributions to non-controlling interest member	(4,427)	(6,136)
Net cash used in financing activities	(81,632)	(94,454)
Net change in cash and cash equivalents	(191)	3,742
Cash and cash equivalents, beginning of period	41,890	48,236
Cash and cash equivalents, end of period	$ 41,699	$ 51,978

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 28, 2018
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. 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, 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 September 9, 2018, the Company entered into a definitive agreement (the Merger Agreement) whereby Science Applications International Corporation (SAIC) will acquire all of the outstanding shares of Engility in a stock-for-stock transaction with each share of Engility common stock exchanged for 0.450 shares of SAIC common stock (the Merger). The transaction is subject to the approval by shareholders of both companies and other customary closing conditions. Transaction costs associated with the pending Merger for legal, financial and other professional advisors totaled $5 million in the three and nine months ended September 28, 2018 and were recorded to selling, general and administrative expenses. Principles of Consolidation and Basis of Presentation: The Unaudited Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and in accordance with Article 10 of Regulation S-X of the U.S. Securities and Exchange Commission (SEC), and reflect the financial position, results of operations and cash flows of our businesses. Accordingly, they do not include all of the disclosures required by U.S. GAAP for a complete set of annual audited financial statements. All significant intercompany accounts and transactions are eliminated in consolidation. The Unaudited Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in our Annual Report on Form 10-K filed with the SEC on March 2, 2018 for the year ended December 31, 2017 (the 2017 Form 10-K). In the opinion of management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement of the results for the interim periods presented have been included. Non-controlling Interest: Engility holds a 50.1% majority interest in Forfeiture Support Associates, LLC (FSA). The results of operations of FSA are included in Engility’s Unaudited Consolidated Financial Statements. The non-controlling interest reported on the Unaudited 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 U.S. 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 revenue and profit recognition for performance obligations satisfied over time, 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. Reporting Periods: Our fiscal year begins on January 1 and ends on December 31. Our 2018 fiscal quarters end on March 30, June 29, September 28 and December 31. Our 2017 fiscal quarters ended on March 31, June 30, September 29 and December 31. Revenue Recognition: On January 1, 2018, we adopted Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No 2014-09, Revenue from Contracts with Customers (ASC 606) using the modified retrospective method. We recognized the cumulative effect of adopting ASC 606 as a decrease to the opening balance of accumulated deficit as of January 1, 2018 of $0.3 million. Revenue for reporting periods beginning after January 1, 2018 are accounted for and presented in accordance with ASC 606, while prior periods were accounted for and continue to be presented in accordance with ASC 605. For further information on the impact of adoption and additional revenue disclosures refer to Notes 2 and 3, respectively. We account for a contract when both we and our customer have approved the contract and are committed to perform our respective obligations, our and our customer’s rights are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. At contract inception, we identify the distinct goods or services promised in the contract, which are referred to as performance obligations. Then we determine the transaction price for the contract, which is the consideration that we expect to be entitled in exchange for the promised goods or services. The transaction price can be a fixed or variable amount. It is common for our contracts to contain award fees, incentive fees or other provisions that can either increase or decrease the transaction price. These variable amounts generally are awarded upon achievement of certain performance metrics, program milestones or cost targets and can be based upon customer discretion. We estimate variable consideration as the most likely amount to which we expect to be entitled. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Our estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of our anticipated performance and historical, current and forecasted information that is reasonably available to us. The transaction price is allocated to each performance obligation using our best estimate of the standalone selling price of each distinct good or service promised in the contract. The primary method used to estimate standalone selling price is the expected cost plus a margin approach, under which we forecast our expected costs of satisfying a performance obligation and then add an appropriate margin for that distinct good or service promised. Revenue is recognized when, or as, the performance obligation is satisfied. Determining a measure of progress and transfer of control requires us to make judgments that affect the timing of revenue recognized. We recognize revenue over time when there is a transfer over time of control to our customer. For our U.S. government contracts, this transfer of control to the customer over time is supported by clauses in the contract that allow the U.S. government to unilaterally terminate the contract for convenience, pay us for costs incurred plus a reasonable profit and take control of any work in process. When control is transferred over time, revenue is recognized based on the extent of progress towards completion of the performance obligation. Based on the nature of the products and services provided in the contract, we use our judgment to determine if an input measure or output measure best depicts the transfer of control over time. For services contracts, we typically satisfy our performance obligations as services are rendered and use a contract cost-based input method to measure progress. Contract costs include labor, material, other direct costs, and allocated indirect costs. Revenue is recognized proportionally as contract costs are incurred plus estimated profit. For time-and-material, time-and-material level of effort, cost plus fixed fee, cost plus fixed fee level of effort, and cost reimbursable (no fee applied) contracts, under which we bill the customer per labor hour and per material/cost, revenue is recognized in the amount the Company has a right to invoice using the right to invoice method since the amount invoiced corresponds directly to the value transferred to the customer. For stand-ready service contracts, a straight-line, time-elapsed output method is used to measure progress and recognize revenue over the term of the contract. If a contract does not meet the criteria for recognizing revenue over time, we recognize revenue at a point in time. Revenue is recognized at the point in time when control of the good or service is transferred to our customer. We consider control to be transferred based on a variety of factors, including when we have a present right to payment, our customer has legal title, we have transferred physical possession, our customer has significant risks and rewards of ownership or when our customer has accepted the good or service. Contracts are often modified to account for changes in contract specifications and requirements. We consider contract modifications to exist when the modification changes the scope and / or price of a contract that has been agreed by the parties. Most of Engility’s contract modifications are for goods or services that are not distinct in the context of the contract and are therefore accounted for as part of the original performance obligations and recognized as an adjustment to revenue under the cumulative catch-up method at the date of the modification. Furthermore, a change in one or more of our estimates of cost or variable consideration could affect the profitability of our contracts. We recognize the impact of such changes using the cumulative catch-up method in the period the change is identified. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, we recognize the total estimated loss in the quarter it is identified. Results for periods prior to adoption were accounted for and continue to be presented in accordance with ASC 605, Revenue Recognition Revenue Recognition – Construction-Type and Production-Type Contracts Billed receivables : Amounts billed and due from our customers are classified as accounts receivables, net on the unaudited consolidated balance sheet. The portion of the payments retained by the customer until final contract settlement is not considered a significant financing component because the intent is to protect the customer in the event we do not perform on our obligations under the contract. Contract assets : Represents unbilled receivables, as classified on the unaudited consolidated balance sheet, resulting from sales under contracts when revenue is recognized over time and revenue recognized exceeds the amounts billed. Amounts are invoiced as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Cost of fulfilling a contract that meet the capitalization criteria result in contract assets. Our contract assets are presented on a contract-by-contract net basis at the end of each reporting period. Included in unbilled receivables 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 September 28, 2018 and December 31, 2017, these receivables were approximately $6 million and $9 million, respectively, 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. Contract liabilities: Represents advance payments and billings in excess of costs incurred as classified on the unaudited consolidated balance sheet. Under certain contracts we receive advances and milestone payments from our customers that exceed revenue earned to date, resulting in contract liabilities. Advances typically are not considered a significant financing component because it is used to meet working capital demands that can be higher in the early stages of a contract and to protect us from the customer failing to adequately complete some or all of its obligations under the contract. Our contract liabilities are presented on a contract-by-contract net basis at the end of each reporting period. Income Taxes: As of September 28, 2018, management has determined it is more likely than not a portion of state deferred tax assets, charitable donations, and foreign tax credits will not be realized and has recorded a 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. Earnings per Share: Basic earnings per share (EPS) is computed by dividing net income (loss) attributable to Engility by the weighted average number of common shares 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 (RSUs), performance shares, performance retention awards and performance units calculated using the treasury stock method. For the three months ended September 28, 2018 and September 29, 2017, no shares were excluded from diluted EPS due to their anti-dilutive effects. For the nine months ended September 28, 2018 and September 29, 2017, 71 shares and 10,949 shares, respectively, were excluded from diluted EPS due to their anti-dilutive effects. The calculation of basic and diluted EPS are presented in the table below (shares in thousands). Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Net income attributable to Engility $ 4,282 $ 9,805 $ 22,698 $ 24,369 Weighted average number of shares outstanding – Basic 36,968 36,809 36,928 36,831 Dilutive effect of share-based compensation outstanding after application of the treasury stock method 814 539 809 523 Weighted average number of shares outstanding – Diluted 37,782 37,348 37,737 37,354 Earnings per share attributable to Engility Basic $ 0.12 $ 0.27 $ 0.61 $ 0.66 Diluted $ 0.11 $ 0.26 $ 0.60 $ 0.65 Dispositions: On January 6, 2017, the Company completed the sale of its international development services business, International Resources Group Ltd. (IRG), for an initial purchase price of $25 million in cash, subject to a cash on hand adjustment of $1 million, finalized in the third quarter of 2017, and working capital adjustments, finalized in January 2018, that resulted in a payment of approximately $2 million. The sale was the result of the Company’s strategic review of its businesses 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 expects to receive the indemnity escrow on or about the second anniversary of the sale assuming no claims are made against the escrow funds. During the first quarter of 2017, the Company completed its sale of long-term assets with carrying value totaling $2 million (net of accumulated depreciation of $1 million). The Company recorded a gain on sale of approximately $1 million which was recorded in selling, general and administrative expenses in the accompanying unaudited consolidated statement of operations.

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 28, 2018
Accounting Policies [Abstract]
New Accounting Pronouncements	2. New Accounting Pronouncements New Accounting Pronouncements Adopted In March 2018, the FASB issued ASU 2018-05, Income Taxes (Topic 740), Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118) In February 2018, the FASB issued ASU No. 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In September 2017, the FASB issued ASU No. 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842) In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting In March 2017, the FASB issued ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In November 2016, the FASB issued 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 May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (ASC 606) Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross Versus Net) , Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing Revenue from Contracts with Customers (Topic 606): Narrow Scope Improvements and Practical Expedients; Revenue from Contracts with Customers (Topic 606): Technical Corrections and Improvements, Income Statement – Reporting Comprehensive Income (Topic 220), Revenue Recognition (Topic 605), and Revenue from Contracts with Customers (Topic 606). On January 1, 2018, we adopted ASC 606 using the modified retrospective method. ASC 606 outlines a five-step model whereby revenue is recognized as performance obligations within a contract are satisfied. ASC 606 also requires new, expanded disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with our customers. We recognized the cumulative effect of adopting ASC 606 as a decrease to the opening balance of accumulated deficit as of January 1, 2018 of $0.3 million. Revenue for reporting periods beginning after January 1, 2018 are accounted for and presented in accordance with ASC 606, while prior periods were accounted for and continue to be presented in accordance with ASC 605. As the new standard impacts several of our business processes, systems and controls, the Company developed and implemented a comprehensive project plan to guide through the process of adopting the new standard. To assess the impact of adopting ASC 606, Engility reviewed its contract population by selecting samples upon which to perform detailed contract analyses. These contract analyses entailed reviewing each selected contract to determine the appropriate accounting treatment under ASC 606. These contract reviews were performed in a phased approach, enabling the Company to identify specific ASC 606-related risk areas for subsequent, more focused analyses. We will continue to recognize revenue and profit for the majority of our performance obligations over time as work is performed. For these performance obligations the customer simultaneously receives and consumes the benefits provided by our performance, and there is continuous transfer of control to the customer as costs are incurred. For U.S. government contracts, this continuous transfer of control to the customer is supported by clauses in the contract that allow the customer to unilaterally terminate the contract for convenience, pay us for costs incurred plus a reasonable profit and take control of any work in process. Engility management identified two primary areas that resulted in ASC 606-related impact: • Unfunded Performance Obligations – Engility may perform work under a contract that has not been fully funded if the Company has received an Authorization to Proceed from the customer. Under ASC 605 the Company only recognized revenue to the extent of funding received, deferring revenue, cost and profit on unfunded work until receiving a modification indicating that adequate funds were available. Under ASC 606, the Company evaluates unfunded amounts as variable consideration that are included in its transaction prices, which is generally expected to result in recognition of the revenue, cost and profit earlier as the work is performed. • Customized Products – Some of Engility’s contracts with customers entail building products to customer specifications. Under ASC 605, revenue for these customized products was recognized at the time of product delivery. The Company changed its revenue recognition methodology from point in time to over time for these products, as they meet at least one of the over-time criteria. The following tables show the effect adopting ASC 606 had on our unaudited consolidated financial statements using the modified retrospective method. Unaudited Consolidated Balance Sheets Balances Impact from Impact from as of Adoption of ASC 606 September 28, 2018 ASC 606 for the Nine Under as of Months Ended As Reported ASC 605 January, 1 2018 September 28, 2018 September 28, 2018 Assets: Current assets: Accounts receivables, net $ 75,905 $ — $ — $ 75,905 Unbilled receivables 230,556 5,483 19,420 255,459 Other current assets 42,144 (5,031 ) (18,523 ) 18,590 Deferred tax assets 109,816 (118 ) (234 ) 109,464 Liabilities: Current liabilities: Advance payments and billings in excess of costs incurred 26,261 — — 26,261 Equity: Accumulated deficit (553,148 ) 334 663 (552,151 ) Unaudited Consolidated Statements of Operations For the Three Months Ended September 28, 2018 Balances Impact from as of ASC 606 September 28, 2018 for the Three Under Months Ended As Reported ASC 605 September 28, 2018 September 28, 2018 Revenue $ 467,868 $ 3,339 $ 471,207 Cost of revenue 397,587 2,887 400,474 Operating income 26,356 452 26,808 Provision for income taxes 4,483 118 4,601 Net income attributable to Engility 3,948 334 4,282 For the Nine Months Ended September 28, 2018 Balances Impact from as of ASC 606 September 28, 2018 for the Nine Under Months Ended As Reported ASC 605 September 28, 2018 September 28, 2018 Revenue $ 1,416,861 $ 19,420 $ 1,436,281 Cost of revenue 1,207,139 18,523 1,225,662 Operating income 88,911 897 89,808 Provision for income taxes 10,734 234 10,968 Net income attributable to Engility 22,035 663 22,698 New Accounting Pronouncements Not Yet Adopted In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. Fair Value Measurement In July 2018, the FASB issued ASU 2018-09, Codification Improvements In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic326): Measurement of Credit Losses on Financial Instruments In February 2016, the FASB issued ASU No. 2016-02, Leases, which revises the accounting related to lessee accounting. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements Codification Improvements to Topic 842, Leases.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 28, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	3. Revenue from Contracts with Customers We account for revenue in accordance with ASC 606, which we adopted on January 1, 2018, using the modified retrospective method. Results for reporting periods beginning after January 1, 2018 are accounted for and presented under ASC 606, while prior periods were accounted for and continue to be reported in accordance with ASC 605. We recognized the cumulative effect of adopting ASC 606 as a decrease to the opening balance of accumulated deficit as of January 1, 2018 of $0.3 million. The cumulative impact of adoption was primarily driven by recognizing revenue for unfunded performance obligations, which is further explained in Note 2. The impact to revenue for the three and nine months ended September 28, 2018 was an increase of $3 million and $19 million, respectively, primarily as a result of changing the revenue recognition for the sale of certain products from a point in time measurement to a measurement over a period of time, which is further explained in Note 2. We have a quarterly estimate at completion process in which management reviews the progress and execution of our performance obligations. As part of this process, management reviews information including, but not limited to, any outstanding key contract matters, progress towards completion and the related program schedule, identified risks and opportunities and the related changes in estimates of revenue and costs. The risks and opportunities include management’s judgment about the ability and cost to achieve the contract milestones and other technical contract requirements. Management must make estimates regarding labor productivity and availability, the complexity of the work to be performed, the availability of materials, the length of time to complete the performance obligation, execution by our subcontractors, the availability and timing of funding from our customer and overhead cost rates, among other variables. A significant change in one or more of these estimates could affect the profitability of our contracts. For the three months ended September 28, 2018, the recognized amounts related to changes in estimates at completion represented a net increase to revenue and operating income of $2 million, of which $1 million was directly related to favorable performance on contract award fees. For the nine months ended September 28, 2018, the net impact of adjustments to contract estimates increased our revenue and operating income by $6 million, of which $2 million was directly related to favorable performance on contract award fees. Amounts related to changes in estimates at completion for the three months ended September 29, 2017 represented a net increase to revenue and operating income of $4 million, of which $1 million was directly related to favorable performance on contract award fees. Amounts related to changes in estimates at completion for the nine months ended September 29, 2017 represented a net increase to revenue and operating income of $9 million, of which $2 million was directly related to favorable performance on contract award fees. No adjustment on any one contract was material to our unaudited consolidated financial statements for the three and nine months ended September 28, 2018 or September 29, 2017. The following table discloses the aggregate amount of the transaction price allocated to our remaining performance obligations as of September 28, 2018 and when we expect to recognize the amounts as revenue. Expected Recognition of Revenue For the Remaining Total Remaining Three Months Performance Ending For the Year Ending Obligation December 31, 2018 December 31, 2019 December 31, 2020 Thereafter $ 1,078,401 $ 411,223 $ 560,786 $ 71,343 $ 35,049 Our performance obligations are satisfied over time or at a point in time. Revenue from contracts that transferred control to customers over time accounted for substantially all of our revenue from contracts with customers for the three and nine months ended September 28, 2018. Changes in the balances of contract assets and contract liabilities are primarily due to the timing difference between our performance and our customer’s payment. The opening balances for contract assets and liabilities at January 1, 2018 were $228 million and $30 million, respectively. For the three and nine months ended September 28, 2018, the amount of revenue that was included in advance payments and billings in excess of costs incurred balances at January 1, 2018 was $3 million and $14 million, respectively. For the three and nine months ended September 28, 2018 and September 29, 2017, impairment losses on our billed receivables and unbilled receivables were immaterial. The following tables disclose our revenue disaggregated by several categories. Revenue by Contract Type Three Months Ended September 28, 2018 September 29, 2017 Cost plus $ 295,509 62.7 % $ 314,880 64.6 % Time and material 93,320 19.8 % 91,563 18.8 % Fixed price 82,378 17.5 % 80,701 16.6 % Total $ 471,207 100.0 % $ 487,144 100.0 % Nine Months Ended September 28, 2018 September 29, 2017 Cost plus $ 921,423 64.2 % $ 924,524 63.0 % Time and material 263,089 18.3 % 284,186 19.4 % Fixed price 251,769 17.5 % 258,320 17.6 % Total $ 1,436,281 100.0 % $ 1,467,030 100.0 % Revenue by Customer Market Three Months Ended September 28, 2018 September 29, 2017 DoD $ 176,131 37.4 % $ 193,433 39.7 % Federal Civilian 114,232 24.2 % 111,905 23.0 % Intelligence 180,844 38.4 % 181,806 37.3 % Total $ 471,207 100.0 % $ 487,144 100.0 % Nine Months Ended September 28, 2018 September 29, 2017 DoD $ 557,168 38.8 % $ 590,571 40.3 % Federal Civilian 334,972 23.3 % 342,192 23.3 % Intelligence 544,141 37.9 % 534,267 36.4 % Total $ 1,436,281 100.0 % $ 1,467,030 100.0 % Revenue by Prime and Subcontractor Three Months Ended September 28, 2018 September 29, 2017 Prime $ 388,782 82.5 % $ 407,110 83.6 % Sub 82,425 17.5 % 80,034 16.4 % Total $ 471,207 100.0 % $ 487,144 100.0 % Nine Months Ended September 28, 2018 September 29, 2017 Prime $ 1,182,758 82.3 % $ 1,211,225 82.6 % Sub 253,523 17.7 % 255,805 17.4 % Total $ 1,436,281 100.0 % $ 1,467,030 100.0 %

Accounts Receivables

Accounts Receivables	9 Months Ended
	Sep. 28, 2018
Receivables [Abstract]
Accounts Receivables	4. Accounts Receivables Our receivables principally relate to contracts with the U.S. government and prime contractors or subcontractors of the U.S. government. The components of account receivables are presented in the table below. September 28, December 31, 2018 2017 Account receivables $ 86,332 $ 119,506 Allowance for doubtful accounts (10,427 ) (11,406 ) Account receivables, net $ 75,905 $ 108,100

Identifiable Intangible Assets

Identifiable Intangible Assets	9 Months Ended
	Sep. 28, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Identifiable Intangible Assets	5. Identifiable Intangible Assets Information on our identifiable intangible assets that are subject to amortization is presented in the table below. September 28, 2018 December 31, 2017 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 $ 213,510 $ 331,719 $ 545,229 $ 189,497 $ 355,732 Technology 15 7,000 1,672 5,328 7,000 1,322 5,678 Total $ 552,229 $ 215,182 $ 337,047 $ 552,229 $ 190,819 $ 361,410 Our amortization expense recorded for our identifiable intangible assets is presented in the table below. Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Amortization expense $ 8,120 $ 8,121 $ 24,363 $ 24,363

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 28, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	6. Share-Based Compensation Simultaneously with the execution of the Merger Agreement, Engility’s board of directors approved an amendment to the performance unit awards granted to employees in fiscal years 2017 and 2018. The amendment provides that the number of performance units eligible to vest following a change in control transaction in which a successor assumes the awards shall be determined based on Engility’s actual performance for the performance period assuming the performance period ended on the date immediately preceding the change in control (or December 31, 2018 if the compensation committee of our board of directors (the Compensation Committee) deems appropriate), provided that at least twelve (12) months has elapsed prior to the effective date of the change in control. Engility’s board of directors also approved the conditional acceleration and settlement of certain performance units and time-based restricted stock units granted to the Company’s executive officers and certain other senior employees in 2016, 2017 and 2018. Therefore, if the Merger Agreement is not terminated on or prior to December 21, 2018, certain performance units and restricted stock units will immediately vest and settle on that date. As each of the modifications above is conditioned upon events outside of the Company’s control, unrecognized compensation expense associated with these performance units and restricted stock units will be recognized when management concludes that the conditions for the modification are probable of being met. For the Nine Months Ended September 28, 2018 Performance Units: During the nine months ended September 28, 2018, we granted a total of 201,571 performance units at target level of 100% (with the potential for the delivery of up to 604,713 shares of our common stock at the maximum performance level) to certain of our employees with a grant date fair value of $24.60 per unit. Performance units cliff vest after three years based on our performance at the end of a three-year period beginning January 1, 2018. The number of shares of our common stock that are ultimately vested are based on continued employment and delivered in respect of these performance units will range from 0% to 300% of the target grant amount. The vesting of performance units depends on the Company's performance, as approved by the Compensation Committee based on two metrics: book-to-bill ratio and adjusted operating cash flow, each as measured over a three-year performance period, and subject to adjustments based on the Company’s compounded annual growth rate for revenue over the same period. The performance units may be settled in cash or stock at the sole discretion of the Compensation Committee. Restricted Stock Units: During the nine months ended September 28, 2018, we granted a total of 242,883 RSUs to certain employees with a grant date fair value of $24.81 per unit, of which 1,098 RSUs cliff vest on the first anniversary of the grant date, 11,700 RSUs cliff vest on the second anniversary of the grant date and 230,085 RSUs vest ratably over a term of three years from the grant date. During the nine months ended September 28, 2018, we granted 31,768 RSUs to our independent directors with a grant date fair value of $30.22 per unit, which cliff vest on the first anniversary of the grant date. The number of shares of our common stock that are ultimately vested are based on continued employment or service as a director, as applicable. The RSUs may be settled in cash or stock at the sole discretion of the Compensation Committee. For the Nine Months Ended September 29, 2017 Performance Units: During the nine months ended September 29, 2017, we granted 189,351 performance units at a target level of 100% (with the potential for the delivery of up to 568,053 shares at the maximum performance level) to certain employees with a grant date fair value of $30.54 per unit. Performance units cliff vest after three years based on our performance at the end of a three-year period beginning January 1, 2017. 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 300% of the target grant amount. The vesting of performance units depends on the Company's performance, as approved by the Compensation Committee, based on two metrics: book-to-bill ratio and adjusted operating cash flow, each as measured over a three-year performance period, and subject to adjustments based on the Company’s compounded annual growth rate for revenue over the same period. For performance units granted prior to 2017, the vesting depends on the Company's performance, as approved by the Compensation Committee, based on two metrics: revenue and adjusted operating cash flow, each as measured over a three-year performance period, and subject to adjustments based on the Company’s compounded annual growth rate for revenue over the same period. The performance units may be settled in cash or stock at the sole discretion of the Compensation Committee. Restricted Stock Units: During the nine months ended September 29, 2017, we granted 220,194 RSUs to certain employees with a grant date fair value of $30.44 per unit, of which 775 RSUs cliff vest on the first anniversary of the grant date, 12,137 RSUs cliff vest on the second anniversary of the grant date and 207,282 RSUs vest ratably over the term of three years from the grant date. During the nine months ended September 29, 2017, we granted 29,431 RSUs to our independent directors with a grant date fair value of $28.25 per unit, which cliff vest on the first anniversary of the grant date. The RSUs may be settled in cash or stock at the sole discretion of the Compensation Committee.

Defined Benefit Plans

Defined Benefit Plans	9 Months Ended
	Sep. 28, 2018
Postemployment Benefits [Abstract]
Defined Benefit Plans	7. Defined Benefit Plans The components of net periodic benefit costs for the Company’s defined benefit plans are as follows: Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Service cost $ 200 $ 206 $ 618 $ 617 Interest cost on projected benefit obligation 706 748 2,115 2,245 Expected return on plan assets (970 ) (954 ) (2,918 ) (2,862 ) Net loss amortization 66 95 216 284 Net periodic benefit expense $ 2 $ 95 $ 31 $ 284 Service cost for the Company’s defined benefit plans are recorded to selling, general and administrative costs and other non-related services costs are recorded to other expense (income), net.

Debt

Debt	9 Months Ended
	Sep. 28, 2018
Debt Disclosure [Abstract]
Debt	8. Debt On March 21, 2018 (the Third Amendment Effective Date), Engility Holdings, Inc. and Engility Corporation (the Borrower) entered into Amendment No. 3 (the Third Amendment) to the Credit Agreement, dated as of August 12, 2016, and amended by Amendment No. 1 thereto, dated as of February 13, 2017, and Amendment No. 2 thereto, dated as of August 14, 2017 by and among the Borrower, the Company, the several lenders from time to time parties thereto and Morgan Stanley Senior Funding, Inc., as administrative agent and collateral agent. The parties entered into the Third Amendment in order to reduce the interest rate margins applicable to (i) the Borrower’s senior secured Term B1 loan facility in the original principal amount of $185 million (Existing Term B1 Loans) from 1.75% to 1.25%, in the case of alternate base rate loans, and from 2.75% to 2.25%, in the case of Eurocurrency loans, (ii) the Borrower’s senior secured Term B2 loan facility in the original principal amount of $579 million (Existing Term B2 Loans) from 2.25% to 1.75%, in the case of alternate base rate loans, and from 3.25% to 2.75%, in the case of Eurocurrency loans and (iii) to reallocate $75 million of Existing Term B1 Loans to Term B2 loans. Additionally, on March 22, 2018, the Borrower utilized its incremental facility to procure an additional $25 million of commitments under its senior secured revolving loan facility (the Loan Facility). The 2016 Credit Facility, as amended, requires the Borrower to maintain compliance with a maximum ratio of consolidated first lien secured debt to consolidated EBITDA (the consolidated first lien net leverage ratio) of 5.625 to 1.00, with incremental step downs over time. The consolidated first lien net leverage ratio, which we believe is our most restrictive covenant, 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 September 28, 2018, we were in compliance with all covenants under the 2016 Credit Facility, and our consolidated first lien net leverage ratio was 3.05 to 1.00. As of September 28, 2018 and December 31, 2017 the composition of our debt was as follows: September 28, December 31, 2018 2017 Term Loans $ 638,000 $ 713,000 8.875% Senior Notes due 2024 (the Notes) 300,000 300,000 Other 200 314 Total debt 938,200 1,013,314 Less: current portion of long-term debt (25,260 ) (26,947 ) Less: unamortized original issue discount costs and financing fees (41,083 ) (47,680 ) Long-term debt $ 871,857 $ 938,687 Our availability under the revolving portion of the 2016 Credit Facility was $188 million as of September 28, 2018, with $2 million outstanding under letters of credit. During the nine months ended September 28, 2018, we repaid a total of $75 million of debt under the 2016 Credit Facility, including the prepayment of $56 million of debt. In conjunction with the Third Amendment, we incurred approximately $2 million in fees related to the repricing of term loan debt. These amounts are reflected in interest expense, net in the consolidated statement of operations for the nine months ended September 28, 2018. Our weighted average outstanding loan balance for the three months ended September 28, 2018 was $966 million which accrued interest at a weighted average borrowing rate of approximately 6.05%. Our weighted average outstanding loan balance for the nine months ended September 28, 2018 was $988 million, which accrued interest at a weighted average borrowing rate of approximately 6.05%. Our weighted average outstanding loan balance for the three months ended September 29, 2017 was $1,060 million which accrued interest at a weighted average borrowing rate of approximately 5.85%. Our weighted average outstanding loan balance for the nine months ended September 29, 2017 was $1,088 million, which accrued interest at a weighted average borrowing rate of approximately 5.97%. The carrying value of the term loans, excluding original issue discount, and Notes approximated their fair value at September 28, 2018. 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 U.S. GAAP hierarchy.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 28, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	9. Fair Value Measurements The Company enters into interest rate swap contracts to reduce its exposure to variability in cash flows relating to interest payments on a portion of its outstanding debt payments. These interest rate contracts are designated as cash flow hedges. The effective portion of the derivative’s gain or loss is initially reported in stockholders’ equity (as a component of accumulated other comprehensive income (loss)) and will 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 will be reported in earnings. The Company does not have any derivatives outstanding that are not designated as hedges. During the first quarter of 2017, the Company entered into an interest rate swap agreement for contracts with an initial notional amount of $281 million. These contracts became effective December 29, 2017 and expire on December 31, 2020. The other terms of these instruments are as follows: Contract received: Floating interest rate LIBOR (subject to minimum of 1.00%) Contract paid: Fixed interest rates 1.947% - 1.949% During the second quarter of 2018, the Company entered into an interest rate swap agreement for contracts with an initial notional amount of $167 million. These contracts become effective April 30, 2019 and expire on July 29, 2022. The other terms of these instruments are as follows: Contract received: Floating interest rate LIBOR (subject to minimum of 1.00%) Contract paid: Fixed interest rates 2.953% - 2.957% The following table presents our assets and liabilities that are measured at fair value on a recurring basis: September 28, December 31, Balance Sheet Classification Fair Value Hierarchy 2018 2017 Interest rate swap assets Other current assets Level 2 $ 1,478 $ — Interest rate swap assets Other assets Level 2 $ 3,387 $ 1,129 Interest rate swap liabilities Other current liabilities Level 2 $ (81 ) $ (477 ) The Company’s interest rate swap assets and 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. The Company has agreements with each of its derivative counterparties that contain a provision where the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness. If the Company had breached any of these provisions at September 28, 2018, it could have been required to settle its obligations under the agreements at their termination value. As of September 28, 2018, the Company had not posted any collateral related to these agreements.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 28, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Procurement Regulations: Most 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. In the ordinary course of business, we cooperate with the U.S. government on 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. We do not currently 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 suspension 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, which would have a materially adverse effect on our consolidated financial position, results of operations and cash flows. 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 and Other 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. Although we cannot predict the outcome of these and other proceedings with certainty, we believe that they will not have a material adverse effect on our consolidated financial position, results of operations or cash flows. 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 for 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 our consolidated balance sheets. Amounts recoverable from insurance contracts or third parties are recorded as assets when deemed probable. At December 31, 2017 and September 28, 2018, 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 we have recorded adequate provisions for our litigation matters. We review these provisions quarterly and adjust these provisions to reflect the effect of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular matter.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 28, 2018
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The effective tax rate for the three months ended September 28, 2018 was 45.9% as compared to 34.1% for the three months ended September 29, 2017. The increase in the tax rate was due to the impacts from nondeductible costs related to the pending Merger, partially offset by the tax rate reduction associated with the enactment of the Tax Act which reduced the federal tax rate from 35% in 2017 to 21% in 2018 The effective tax rate for the nine months ended September 28, 2018 was 29.9% as compared to 37.3% for the nine months ended September 29, 2017. The decrease in the effective tax rate was due to the tax rate reduction associated with the Tax Act which reduced the federal tax rate from 35% in 2017 to 21% in 2018

Separate Financial Information

Separate Financial Information of Subsidiary Guarantor of Indebtedness	9 Months Ended
	Sep. 28, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Separate Financial Information of Subsidiary Guarantor of Indebtedness	12. 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 (as defined in Note 11 to our audited consolidated financial statements in our 2017 Form 10-K), 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 an 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. 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. UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 29,343 $ 37 $ 12,319 $ — $ 41,699 Accounts receivables, net — 65,807 2,324 7,774 — 75,905 Unbilled receivables — 239,721 4,338 11,400 — 255,459 Intercompany receivables — — 8,693 12,496 (21,189 ) — Other current assets — 16,962 — 1,628 — 18,590 Total current assets — 351,833 15,392 45,617 (21,189 ) 391,653 Property, plant and equipment, net — 49,445 — 47 — 49,492 Goodwill — 1,071,371 — — — 1,071,371 Identifiable intangible assets, net — 337,047 — — — 337,047 Deferred tax assets — 109,464 — — — 109,464 Investment in subsidiaries 707,789 47,578 33,858 — (789,225 ) — Other assets — 5,741 45 — — 5,786 Total assets $ 707,789 $ 1,972,479 $ 49,295 $ 45,664 $ (810,414 ) $ 1,964,813 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 25,260 $ — $ — $ — $ 25,260 Accounts payable, trade — 44,848 — 52 — 44,900 Intercompany payable — 21,189 — — (21,189 ) — Accrued employment costs — 87,393 1,717 10,194 — 99,304 Accrued expenses — 79,511 — 255 — 79,766 Advance payments and billings in excess of costs incurred — 26,261 — — — 26,261 Income tax liabilities — 180 — 172 352 Other current liabilities — 15,124 — 1,133 16,257 Total current liabilities — 299,766 1,717 11,806 (21,189 ) 292,100 Long-term debt — 871,857 — — — 871,857 Income tax liabilities — 33,080 — — — 33,080 Other liabilities — 59,987 — — — 59,987 Total liabilities — 1,264,690 1,717 11,806 (21,189 ) 1,257,024 Shareholders' equity 707,789 707,789 47,578 33,858 (789,225 ) 707,789 Total liabilities and equity $ 707,789 $ 1,972,479 $ 49,295 $ 45,664 $ (810,414 ) $ 1,964,813 SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF DECEMBER 31, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 31,966 $ 36 $ 9,888 $ — $ 41,890 Accounts receivables, net — 98,125 3,909 6,066 — 108,100 Unbilled receivables — 202,922 5,653 14,419 — 222,994 Intercompany receivables — — 28,069 7,738 (35,807 ) — Other current assets — 17,300 (4 ) 2,385 — 19,681 Total current assets — 350,313 37,663 40,496 (35,807 ) 392,665 Property, plant and equipment, net — 43,933 — 73 — 44,006 Goodwill — 1,071,371 — — — 1,071,371 Identifiable intangible assets, net — 361,410 — — — 361,410 Deferred tax assets — 150,535 — — — 150,535 Investment in subsidiaries 676,105 67,623 31,876 — (775,604 ) — Other assets — 5,976 45 — — 6,021 Total assets $ 676,105 $ 2,051,161 $ 69,584 $ 40,569 $ (811,411 ) $ 2,026,008 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 26,947 $ — $ — $ — $ 26,947 Accounts payable, trade — 52,826 — 128 — 52,954 Intercompany payable — 35,807 — — (35,807 ) — Accrued employment costs — 68,622 1,961 6,962 — 77,545 Accrued expenses — 74,657 — 199 — 74,856 Advance payments and billings in excess of costs incurred — 30,380 — — — 30,380 Income tax liabilities — 320 — 228 548 Other current liabilities — 25,512 — 1,176 26,688 Total current liabilities — 315,071 1,961 8,693 (35,807 ) 289,918 Long-term debt — 938,687 — — — 938,687 Income tax liabilities — 62,219 — — — 62,219 Other liabilities — 59,079 — — — 59,079 Total liabilities — 1,375,056 1,961 8,693 (35,807 ) 1,349,903 Shareholders' equity 676,105 676,105 67,623 31,876 (775,604 ) 676,105 Total liabilities and equity $ 676,105 $ 2,051,161 $ 69,584 $ 40,569 $ (811,411 ) $ 2,026,008 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE THREE MONTHS ENDED SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 432,824 $ 2,650 $ 35,733 $ — $ 471,207 Costs and expenses Cost of revenue — 358,546 9,548 32,380 — 400,474 Selling, general and administrative expenses — 42,171 779 975 — 43,925 Total costs and expenses — 400,717 10,327 33,355 — 444,399 Operating income (loss) — 32,107 (7,677 ) 2,378 — 26,808 Interest expense, net — 16,981 — — — 16,981 Other expenses (income), net — (228 ) — 37 — (191 ) Income (loss) in equity investments in subsidiaries 4,282 (6,471 ) 1,206 — 983 — Income (loss) before income taxes 4,282 8,883 (6,471 ) 2,341 983 10,018 Provision for income taxes — 4,601 — — — 4,601 Net income (loss) 4,282 4,282 (6,471 ) 2,341 983 5,417 Less: Net income attributable to non-controlling interest — — — 1,135 — 1,135 Net income (loss) attributable to Engility $ 4,282 $ 4,282 $ (6,471 ) $ 1,206 $ 983 $ 4,282 Net income (loss) $ 4,282 $ 4,282 $ (6,471 ) $ 2,341 $ 983 $ 5,417 Other comprehensive income — 561 — — — 561 Comprehensive income (loss) 4,282 4,843 (6,471 ) 2,341 983 5,978 Less: Net income attributable to non-controlling interest — — — 1,135 — 1,135 Comprehensive income (loss) attributable to Engility $ 4,282 $ 4,843 $ (6,471 ) $ 1,206 $ 983 $ 4,843 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE THREE MONTHS ENDED SEPTEMBER 29, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 444,689 $ 7,771 $ 34,684 $ — $ 487,144 Costs and expenses Cost of revenue — 372,333 13,530 31,718 — 417,581 Selling, general and administrative expenses — 31,502 774 1,143 — 33,419 Total costs and expenses — 403,835 14,304 32,861 — 451,000 Operating income (loss) — 40,854 (6,533 ) 1,823 — 36,144 Interest expense, net — 19,739 — — — 19,739 Other expenses (income), net — (118 ) (1 ) 57 — (62 ) Income (loss) in equity investments in subsidiaries 9,805 (5,817 ) 715 — (4,703 ) — Income (loss) before income taxes 9,805 15,416 (5,817 ) 1,766 (4,703 ) 16,467 Provision for income taxes — 5,611 — — — 5,611 Net income (loss) 9,805 9,805 (5,817 ) 1,766 (4,703 ) 10,856 Less: Net income attributable to non-controlling interest — — — 1,051 — 1,051 Net income (loss) attributable to Engility $ 9,805 $ 9,805 $ (5,817 ) $ 715 $ (4,703 ) $ 9,805 Net income (loss) $ 9,805 $ 9,805 $ (5,817 ) $ 1,766 $ (4,703 ) $ 10,856 Other comprehensive loss — (55 ) — — — (55 ) Comprehensive income (loss) 9,805 9,750 (5,817 ) 1,766 (4,703 ) 10,801 Less: Net income attributable to non-controlling interest — — — 1,051 — 1,051 Comprehensive income (loss) attributable to Engility $ 9,805 $ 9,750 $ (5,817 ) $ 715 $ (4,703 ) $ 9,750 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE NINE MONTHS ENDED SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,312,973 $ 14,093 $ 109,215 $ — $ 1,436,281 Costs and expenses Cost of revenue — 1,091,600 34,867 99,195 — 1,225,662 Selling, general and administrative expenses — 114,762 2,617 3,432 — 120,811 Total costs and expenses — 1,206,362 37,484 102,627 — 1,346,473 Operating income (loss) — 106,611 (23,391 ) 6,588 — 89,808 Interest expense, net — 53,520 — — — 53,520 Other expenses (income), net — (620 ) — 179 — (441 ) Income (loss) in equity investments in subsidiaries 22,698 (20,045 ) 3,346 — (5,999 ) — Income (loss) before income taxes 22,698 33,666 (20,045 ) 6,409 (5,999 ) 36,729 Provision for income taxes — 10,968 — — — 10,968 Net income (loss) 22,698 22,698 (20,045 ) 6,409 (5,999 ) 25,761 Less: Net income attributable to non-controlling interest — — — 3,063 — 3,063 Net income (loss) attributable to Engility $ 22,698 $ 22,698 $ (20,045 ) $ 3,346 $ (5,999 ) $ 22,698 Net income (loss) $ 22,698 $ 22,698 $ (20,045 ) $ 6,409 $ (5,999 ) $ 25,761 Other comprehensive income — 2,948 — — — 2,948 Comprehensive income (loss) 22,698 25,646 (20,045 ) 6,409 (5,999 ) 28,709 Less: Net income attributable to non-controlling interest — — — 3,063 — 3,063 Comprehensive income (loss) attributable to Engility $ 22,698 $ 25,646 $ (20,045 ) $ 3,346 $ (5,999 ) $ 25,646 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE NINE MONTHS ENDED SEPTEMBER 29, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,335,395 $ 24,165 $ 107,470 $ — $ 1,467,030 Costs and expenses Cost of revenue — 1,117,184 41,527 96,892 — 1,255,603 Selling, general and administrative expenses — 102,064 2,465 3,107 — 107,636 Total costs and expenses — 1,219,248 43,992 99,999 — 1,363,239 Operating income (loss) — 116,147 (19,827 ) 7,471 — 103,791 Interest expense, net — 59,189 — — — 59,189 Other expenses (income), net — (352 ) (3 ) 234 — (121 ) Income (loss) in equity investments in subsidiaries 24,369 (16,270 ) 3,554 — (11,653 ) — Income (loss) before income taxes 24,369 41,040 (16,270 ) 7,237 (11,653 ) 44,723 Provision for income taxes — 16,671 — — — 16,671 Net income (loss) 24,369 24,369 (16,270 ) 7,237 (11,653 ) 28,052 Less: Net income attributable to non-controlling interest — — — 3,683 — 3,683 Net income (loss) attributable to Engility $ 24,369 $ 24,369 $ (16,270 ) $ 3,554 $ (11,653 ) $ 24,369 Net income (loss) $ 24,369 $ 24,369 $ (16,270 ) $ 7,237 $ (11,653 ) $ 28,052 Other comprehensive loss — (639 ) — — — (639 ) Comprehensive income (loss) 24,369 23,730 (16,270 ) 7,237 (11,653 ) 27,413 Less: Net income attributable to non-controlling interest — — — 3,683 — 3,683 Comprehensive income (loss) attributable to Engility $ 24,369 $ 23,730 $ (16,270 ) $ 3,554 $ (11,653 ) $ 23,730 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE NINE MONTHS ENDED SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by (used in) operating activities $ — $ 102,504 $ (19,375 ) $ 11,616 $ — $ 94,745 Investing activities: Payments from sale of business — (1,900 ) — — — (1,900 ) Capital expenditures — (11,404 ) — — — (11,404 ) Net cash used in investing activities — (13,304 ) — — — (13,304 ) Financing activities: Repayment of long-term debt — (75,115 ) — — — (75,115 ) Gross borrowings from revolving credit facility — 167,000 — — — 167,000 Repayments of revolving credit facility — (167,000 ) — — — (167,000 ) Debt issuance costs — (45 ) — — — (45 ) Payment of employee withholding taxes on share-based compensation (2,045 ) — — — — (2,045 ) Distributions to non-controlling interest member — — — (4,427 ) — (4,427 ) Due (to) from subsidiaries 2,045 (16,663 ) 19,376 (4,758 ) — — Net cash provided by (used in) financing activities — (91,823 ) 19,376 (9,185 ) — (81,632 ) Net change in cash and cash equivalents — (2,623 ) 1 2,431 — (191 ) Cash and cash equivalents, beginning of period — 31,966 36 9,888 — 41,890 Cash and cash equivalents, end of period $ — $ 29,343 $ 37 $ 12,319 $ — $ 41,699 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE NINE MONTHS ENDED SEPTEMBER 29, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ 72,527 $ (4,099 ) $ 10,327 $ — $ 78,755 Investing activities: Proceeds from sale of business, net of amount placed in escrow — 22,349 — — — 22,349 Proceeds from sale of property, plant and equipment — 2,902 — — — 2,902 Capital expenditures — (5,810 ) — — — (5,810 ) Net cash provided by investing activities — 19,441 — — — 19,441 Financing activities: Repayment of long-term debt — (86,410 ) — — — (86,410 ) Gross borrowings from revolving credit facility — 270,000 — — — 270,000 Repayments of revolving credit facility — (270,000 ) — — — (270,000 ) Payment of employee withholding taxes on share-based compensation (1,501 ) — — — — (1,501 ) Dividends paid (407 ) — — — — (407 ) Distributions to non-controlling interest member — — — (6,136 ) — (6,136 ) Due (to) from subsidiaries 1,908 (222 ) 3,840 (5,526 ) — — Net cash provided by (used in) financing activities — (86,632 ) 3,840 (11,662 ) — (94,454 ) Net change in cash and cash equivalents — 5,336 (259 ) (1,335 ) — 3,742 Cash and cash equivalents, beginning of period — 31,124 385 16,727 — 48,236 Cash and cash equivalents, end of period $ — $ 36,460 $ 126 $ 15,392 $ — $ 51,978

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 28, 2018
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. 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, 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 September 9, 2018, the Company entered into a definitive agreement (the Merger Agreement) whereby Science Applications International Corporation (SAIC) will acquire all of the outstanding shares of Engility in a stock-for-stock transaction with each share of Engility common stock exchanged for 0.450 shares of SAIC common stock (the Merger). The transaction is subject to the approval by shareholders of both companies and other customary closing conditions. Transaction costs associated with the pending Merger for legal, financial and other professional advisors totaled $5 million in the three and nine months ended September 28, 2018 and were recorded to selling, general and administrative expenses.
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation: The Unaudited Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and in accordance with Article 10 of Regulation S-X of the U.S. Securities and Exchange Commission (SEC), and reflect the financial position, results of operations and cash flows of our businesses. Accordingly, they do not include all of the disclosures required by U.S. GAAP for a complete set of annual audited financial statements. All significant intercompany accounts and transactions are eliminated in consolidation. The Unaudited Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. The accompanying financial information should be read in conjunction with the consolidated financial statements and notes thereto contained in our Annual Report on Form 10-K filed with the SEC on March 2, 2018 for the year ended December 31, 2017 (the 2017 Form 10-K). In the opinion of management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement of the results for the interim periods presented have been included.
Non-controlling Interest	Non-controlling Interest: Engility holds a 50.1% majority interest in Forfeiture Support Associates, LLC (FSA). The results of operations of FSA are included in Engility’s Unaudited Consolidated Financial Statements. The non-controlling interest reported on the Unaudited 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 U.S. 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 revenue and profit recognition for performance obligations satisfied over time, 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.
Reporting Periods	Reporting Periods: Our fiscal year begins on January 1 and ends on December 31. Our 2018 fiscal quarters end on March 30, June 29, September 28 and December 31. Our 2017 fiscal quarters ended on March 31, June 30, September 29 and December 31.
Revenue Recognition	Revenue Recognition: On January 1, 2018, we adopted Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No 2014-09, Revenue from Contracts with Customers (ASC 606) using the modified retrospective method. We recognized the cumulative effect of adopting ASC 606 as a decrease to the opening balance of accumulated deficit as of January 1, 2018 of $0.3 million. Revenue for reporting periods beginning after January 1, 2018 are accounted for and presented in accordance with ASC 606, while prior periods were accounted for and continue to be presented in accordance with ASC 605. For further information on the impact of adoption and additional revenue disclosures refer to Notes 2 and 3, respectively. We account for a contract when both we and our customer have approved the contract and are committed to perform our respective obligations, our and our customer’s rights are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. At contract inception, we identify the distinct goods or services promised in the contract, which are referred to as performance obligations. Then we determine the transaction price for the contract, which is the consideration that we expect to be entitled in exchange for the promised goods or services. The transaction price can be a fixed or variable amount. It is common for our contracts to contain award fees, incentive fees or other provisions that can either increase or decrease the transaction price. These variable amounts generally are awarded upon achievement of certain performance metrics, program milestones or cost targets and can be based upon customer discretion. We estimate variable consideration as the most likely amount to which we expect to be entitled. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Our estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of our anticipated performance and historical, current and forecasted information that is reasonably available to us. The transaction price is allocated to each performance obligation using our best estimate of the standalone selling price of each distinct good or service promised in the contract. The primary method used to estimate standalone selling price is the expected cost plus a margin approach, under which we forecast our expected costs of satisfying a performance obligation and then add an appropriate margin for that distinct good or service promised. Revenue is recognized when, or as, the performance obligation is satisfied. Determining a measure of progress and transfer of control requires us to make judgments that affect the timing of revenue recognized. We recognize revenue over time when there is a transfer over time of control to our customer. For our U.S. government contracts, this transfer of control to the customer over time is supported by clauses in the contract that allow the U.S. government to unilaterally terminate the contract for convenience, pay us for costs incurred plus a reasonable profit and take control of any work in process. When control is transferred over time, revenue is recognized based on the extent of progress towards completion of the performance obligation. Based on the nature of the products and services provided in the contract, we use our judgment to determine if an input measure or output measure best depicts the transfer of control over time. For services contracts, we typically satisfy our performance obligations as services are rendered and use a contract cost-based input method to measure progress. Contract costs include labor, material, other direct costs, and allocated indirect costs. Revenue is recognized proportionally as contract costs are incurred plus estimated profit. For time-and-material, time-and-material level of effort, cost plus fixed fee, cost plus fixed fee level of effort, and cost reimbursable (no fee applied) contracts, under which we bill the customer per labor hour and per material/cost, revenue is recognized in the amount the Company has a right to invoice using the right to invoice method since the amount invoiced corresponds directly to the value transferred to the customer. For stand-ready service contracts, a straight-line, time-elapsed output method is used to measure progress and recognize revenue over the term of the contract. If a contract does not meet the criteria for recognizing revenue over time, we recognize revenue at a point in time. Revenue is recognized at the point in time when control of the good or service is transferred to our customer. We consider control to be transferred based on a variety of factors, including when we have a present right to payment, our customer has legal title, we have transferred physical possession, our customer has significant risks and rewards of ownership or when our customer has accepted the good or service. Contracts are often modified to account for changes in contract specifications and requirements. We consider contract modifications to exist when the modification changes the scope and / or price of a contract that has been agreed by the parties. Most of Engility’s contract modifications are for goods or services that are not distinct in the context of the contract and are therefore accounted for as part of the original performance obligations and recognized as an adjustment to revenue under the cumulative catch-up method at the date of the modification. Furthermore, a change in one or more of our estimates of cost or variable consideration could affect the profitability of our contracts. We recognize the impact of such changes using the cumulative catch-up method in the period the change is identified. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, we recognize the total estimated loss in the quarter it is identified. Results for periods prior to adoption were accounted for and continue to be presented in accordance with ASC 605, Revenue Recognition Revenue Recognition – Construction-Type and Production-Type Contracts
Billed Receivables	Billed receivables : Amounts billed and due from our customers are classified as accounts receivables, net on the unaudited consolidated balance sheet. The portion of the payments retained by the customer until final contract settlement is not considered a significant financing component because the intent is to protect the customer in the event we do not perform on our obligations under the contract.
Contract Assets	Contract assets : Represents unbilled receivables, as classified on the unaudited consolidated balance sheet, resulting from sales under contracts when revenue is recognized over time and revenue recognized exceeds the amounts billed. Amounts are invoiced as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Cost of fulfilling a contract that meet the capitalization criteria result in contract assets. Our contract assets are presented on a contract-by-contract net basis at the end of each reporting period. Included in unbilled receivables 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 September 28, 2018 and December 31, 2017, these receivables were approximately $6 million and $9 million, respectively, 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.
Contract Liabilities	Contract liabilities: Represents advance payments and billings in excess of costs incurred as classified on the unaudited consolidated balance sheet. Under certain contracts we receive advances and milestone payments from our customers that exceed revenue earned to date, resulting in contract liabilities. Advances typically are not considered a significant financing component because it is used to meet working capital demands that can be higher in the early stages of a contract and to protect us from the customer failing to adequately complete some or all of its obligations under the contract. Our contract liabilities are presented on a contract-by-contract net basis at the end of each reporting period.
Income Taxes	Income Taxes: As of September 28, 2018, management has determined it is more likely than not a portion of state deferred tax assets, charitable donations, and foreign tax credits will not be realized and has recorded a 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.
Earnings Per Share	Earnings per Share: Basic earnings per share (EPS) is computed by dividing net income (loss) attributable to Engility by the weighted average number of common shares 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 (RSUs), performance shares, performance retention awards and performance units calculated using the treasury stock method. For the three months ended September 28, 2018 and September 29, 2017, no shares were excluded from diluted EPS due to their anti-dilutive effects. For the nine months ended September 28, 2018 and September 29, 2017, 71 shares and 10,949 shares, respectively, were excluded from diluted EPS due to their anti-dilutive effects. The calculation of basic and diluted EPS are presented in the table below (shares in thousands). Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Net income attributable to Engility $ 4,282 $ 9,805 $ 22,698 $ 24,369 Weighted average number of shares outstanding – Basic 36,968 36,809 36,928 36,831 Dilutive effect of share-based compensation outstanding after application of the treasury stock method 814 539 809 523 Weighted average number of shares outstanding – Diluted 37,782 37,348 37,737 37,354 Earnings per share attributable to Engility Basic $ 0.12 $ 0.27 $ 0.61 $ 0.66 Diluted $ 0.11 $ 0.26 $ 0.60 $ 0.65
Dispositions	Dispositions: On January 6, 2017, the Company completed the sale of its international development services business, International Resources Group Ltd. (IRG), for an initial purchase price of $25 million in cash, subject to a cash on hand adjustment of $1 million, finalized in the third quarter of 2017, and working capital adjustments, finalized in January 2018, that resulted in a payment of approximately $2 million. The sale was the result of the Company’s strategic review of its businesses 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 expects to receive the indemnity escrow on or about the second anniversary of the sale assuming no claims are made against the escrow funds. During the first quarter of 2017, the Company completed its sale of long-term assets with carrying value totaling $2 million (net of accumulated depreciation of $1 million). The Company recorded a gain on sale of approximately $1 million which was recorded in selling, general and administrative expenses in the accompanying unaudited consolidated statement of operations.
New Accounting Pronouncements Adopted	New Accounting Pronouncements Adopted In March 2018, the FASB issued ASU 2018-05, Income Taxes (Topic 740), Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118) In February 2018, the FASB issued ASU No. 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In September 2017, the FASB issued ASU No. 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842) In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting In March 2017, the FASB issued ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In November 2016, the FASB issued 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 May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (ASC 606) Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross Versus Net) , Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing Revenue from Contracts with Customers (Topic 606): Narrow Scope Improvements and Practical Expedients; Revenue from Contracts with Customers (Topic 606): Technical Corrections and Improvements, Income Statement – Reporting Comprehensive Income (Topic 220), Revenue Recognition (Topic 605), and Revenue from Contracts with Customers (Topic 606). On January 1, 2018, we adopted ASC 606 using the modified retrospective method. ASC 606 outlines a five-step model whereby revenue is recognized as performance obligations within a contract are satisfied. ASC 606 also requires new, expanded disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with our customers. We recognized the cumulative effect of adopting ASC 606 as a decrease to the opening balance of accumulated deficit as of January 1, 2018 of $0.3 million. Revenue for reporting periods beginning after January 1, 2018 are accounted for and presented in accordance with ASC 606, while prior periods were accounted for and continue to be presented in accordance with ASC 605. As the new standard impacts several of our business processes, systems and controls, the Company developed and implemented a comprehensive project plan to guide through the process of adopting the new standard. To assess the impact of adopting ASC 606, Engility reviewed its contract population by selecting samples upon which to perform detailed contract analyses. These contract analyses entailed reviewing each selected contract to determine the appropriate accounting treatment under ASC 606. These contract reviews were performed in a phased approach, enabling the Company to identify specific ASC 606-related risk areas for subsequent, more focused analyses. We will continue to recognize revenue and profit for the majority of our performance obligations over time as work is performed. For these performance obligations the customer simultaneously receives and consumes the benefits provided by our performance, and there is continuous transfer of control to the customer as costs are incurred. For U.S. government contracts, this continuous transfer of control to the customer is supported by clauses in the contract that allow the customer to unilaterally terminate the contract for convenience, pay us for costs incurred plus a reasonable profit and take control of any work in process. Engility management identified two primary areas that resulted in ASC 606-related impact: • Unfunded Performance Obligations – Engility may perform work under a contract that has not been fully funded if the Company has received an Authorization to Proceed from the customer. Under ASC 605 the Company only recognized revenue to the extent of funding received, deferring revenue, cost and profit on unfunded work until receiving a modification indicating that adequate funds were available. Under ASC 606, the Company evaluates unfunded amounts as variable consideration that are included in its transaction prices, which is generally expected to result in recognition of the revenue, cost and profit earlier as the work is performed. • Customized Products – Some of Engility’s contracts with customers entail building products to customer specifications. Under ASC 605, revenue for these customized products was recognized at the time of product delivery. The Company changed its revenue recognition methodology from point in time to over time for these products, as they meet at least one of the over-time criteria. The following tables show the effect adopting ASC 606 had on our unaudited consolidated financial statements using the modified retrospective method. Unaudited Consolidated Balance Sheets Balances Impact from Impact from as of Adoption of ASC 606 September 28, 2018 ASC 606 for the Nine Under as of Months Ended As Reported ASC 605 January, 1 2018 September 28, 2018 September 28, 2018 Assets: Current assets: Accounts receivables, net $ 75,905 $ — $ — $ 75,905 Unbilled receivables 230,556 5,483 19,420 255,459 Other current assets 42,144 (5,031 ) (18,523 ) 18,590 Deferred tax assets 109,816 (118 ) (234 ) 109,464 Liabilities: Current liabilities: Advance payments and billings in excess of costs incurred 26,261 — — 26,261 Equity: Accumulated deficit (553,148 ) 334 663 (552,151 ) Unaudited Consolidated Statements of Operations For the Three Months Ended September 28, 2018 Balances Impact from as of ASC 606 September 28, 2018 for the Three Under Months Ended As Reported ASC 605 September 28, 2018 September 28, 2018 Revenue $ 467,868 $ 3,339 $ 471,207 Cost of revenue 397,587 2,887 400,474 Operating income 26,356 452 26,808 Provision for income taxes 4,483 118 4,601 Net income attributable to Engility 3,948 334 4,282 For the Nine Months Ended September 28, 2018 Balances Impact from as of ASC 606 September 28, 2018 for the Nine Under Months Ended As Reported ASC 605 September 28, 2018 September 28, 2018 Revenue $ 1,416,861 $ 19,420 $ 1,436,281 Cost of revenue 1,207,139 18,523 1,225,662 Operating income 88,911 897 89,808 Provision for income taxes 10,734 234 10,968 Net income attributable to Engility 22,035 663 22,698
New Accounting Pronouncements Not Yet Adopted	New Accounting Pronouncements Not Yet Adopted In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. Fair Value Measurement In July 2018, the FASB issued ASU 2018-09, Codification Improvements In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic326): Measurement of Credit Losses on Financial Instruments In February 2016, the FASB issued ASU No. 2016-02, Leases, which revises the accounting related to lessee accounting. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements Codification Improvements to Topic 842, Leases.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 28, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Calculation of Basic and Diluted EPS	The calculation of basic and diluted EPS are presented in the table below (shares in thousands). Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Net income attributable to Engility $ 4,282 $ 9,805 $ 22,698 $ 24,369 Weighted average number of shares outstanding – Basic 36,968 36,809 36,928 36,831 Dilutive effect of share-based compensation outstanding after application of the treasury stock method 814 539 809 523 Weighted average number of shares outstanding – Diluted 37,782 37,348 37,737 37,354 Earnings per share attributable to Engility Basic $ 0.12 $ 0.27 $ 0.61 $ 0.66 Diluted $ 0.11 $ 0.26 $ 0.60 $ 0.65

New Accounting Pronouncements (

New Accounting Pronouncements (Tables)	9 Months Ended
	Sep. 28, 2018
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Summary of Effect Adopting ASC 606 on Unaudited Consolidated Financial Statements	The following tables show the effect adopting ASC 606 had on our unaudited consolidated financial statements using the modified retrospective method. Unaudited Consolidated Balance Sheets Balances Impact from Impact from as of Adoption of ASC 606 September 28, 2018 ASC 606 for the Nine Under as of Months Ended As Reported ASC 605 January, 1 2018 September 28, 2018 September 28, 2018 Assets: Current assets: Accounts receivables, net $ 75,905 $ — $ — $ 75,905 Unbilled receivables 230,556 5,483 19,420 255,459 Other current assets 42,144 (5,031 ) (18,523 ) 18,590 Deferred tax assets 109,816 (118 ) (234 ) 109,464 Liabilities: Current liabilities: Advance payments and billings in excess of costs incurred 26,261 — — 26,261 Equity: Accumulated deficit (553,148 ) 334 663 (552,151 ) Unaudited Consolidated Statements of Operations For the Three Months Ended September 28, 2018 Balances Impact from as of ASC 606 September 28, 2018 for the Three Under Months Ended As Reported ASC 605 September 28, 2018 September 28, 2018 Revenue $ 467,868 $ 3,339 $ 471,207 Cost of revenue 397,587 2,887 400,474 Operating income 26,356 452 26,808 Provision for income taxes 4,483 118 4,601 Net income attributable to Engility 3,948 334 4,282 For the Nine Months Ended September 28, 2018 Balances Impact from as of ASC 606 September 28, 2018 for the Nine Under Months Ended As Reported ASC 605 September 28, 2018 September 28, 2018 Revenue $ 1,416,861 $ 19,420 $ 1,436,281 Cost of revenue 1,207,139 18,523 1,225,662 Operating income 88,911 897 89,808 Provision for income taxes 10,734 234 10,968 Net income attributable to Engility 22,035 663 22,698

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 28, 2018
Revenue From Contract With Customer [Abstract]
Aggregate Amount of Transaction Price Allocated to Remaining Performance Obligations	The following table discloses the aggregate amount of the transaction price allocated to our remaining performance obligations as of September 28, 2018 and when we expect to recognize the amounts as revenue. Expected Recognition of Revenue For the Remaining Total Remaining Three Months Performance Ending For the Year Ending Obligation December 31, 2018 December 31, 2019 December 31, 2020 Thereafter $ 1,078,401 $ 411,223 $ 560,786 $ 71,343 $ 35,049
Summary of Revenue Disaggregated by Several Categories	The following tables disclose our revenue disaggregated by several categories. Revenue by Contract Type Three Months Ended September 28, 2018 September 29, 2017 Cost plus $ 295,509 62.7 % $ 314,880 64.6 % Time and material 93,320 19.8 % 91,563 18.8 % Fixed price 82,378 17.5 % 80,701 16.6 % Total $ 471,207 100.0 % $ 487,144 100.0 % Nine Months Ended September 28, 2018 September 29, 2017 Cost plus $ 921,423 64.2 % $ 924,524 63.0 % Time and material 263,089 18.3 % 284,186 19.4 % Fixed price 251,769 17.5 % 258,320 17.6 % Total $ 1,436,281 100.0 % $ 1,467,030 100.0 % Revenue by Customer Market Three Months Ended September 28, 2018 September 29, 2017 DoD $ 176,131 37.4 % $ 193,433 39.7 % Federal Civilian 114,232 24.2 % 111,905 23.0 % Intelligence 180,844 38.4 % 181,806 37.3 % Total $ 471,207 100.0 % $ 487,144 100.0 % Nine Months Ended September 28, 2018 September 29, 2017 DoD $ 557,168 38.8 % $ 590,571 40.3 % Federal Civilian 334,972 23.3 % 342,192 23.3 % Intelligence 544,141 37.9 % 534,267 36.4 % Total $ 1,436,281 100.0 % $ 1,467,030 100.0 % Revenue by Prime and Subcontractor Three Months Ended September 28, 2018 September 29, 2017 Prime $ 388,782 82.5 % $ 407,110 83.6 % Sub 82,425 17.5 % 80,034 16.4 % Total $ 471,207 100.0 % $ 487,144 100.0 % Nine Months Ended September 28, 2018 September 29, 2017 Prime $ 1,182,758 82.3 % $ 1,211,225 82.6 % Sub 253,523 17.7 % 255,805 17.4 % Total $ 1,436,281 100.0 % $ 1,467,030 100.0 %

Accounts Receivables (Tables)

Accounts Receivables (Tables)	9 Months Ended
	Sep. 28, 2018
Receivables [Abstract]
Components of Account Receivables	The components of account receivables are presented in the table below. September 28, December 31, 2018 2017 Account receivables $ 86,332 $ 119,506 Allowance for doubtful accounts (10,427 ) (11,406 ) Account receivables, net $ 75,905 $ 108,100

Identifiable Intangible Assets

Identifiable Intangible Assets (Tables)	9 Months Ended
	Sep. 28, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Information on Identifiable Intangible Assets	Information on our identifiable intangible assets that are subject to amortization is presented in the table below. September 28, 2018 December 31, 2017 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 $ 213,510 $ 331,719 $ 545,229 $ 189,497 $ 355,732 Technology 15 7,000 1,672 5,328 7,000 1,322 5,678 Total $ 552,229 $ 215,182 $ 337,047 $ 552,229 $ 190,819 $ 361,410
Amortization Expense Recorded for Identifiable Intangible Assets	Our amortization expense recorded for our identifiable intangible assets is presented in the table below. Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Amortization expense $ 8,120 $ 8,121 $ 24,363 $ 24,363

Defined Benefit Plans (Tables)

Defined Benefit Plans (Tables)	9 Months Ended
	Sep. 28, 2018
Postemployment Benefits [Abstract]
Components of Net Periodic Benefit Costs for Defined Benefit Plans	The components of net periodic benefit costs for the Company’s defined benefit plans are as follows: Three Months Ended Nine Months Ended September 28, 2018 September 29, 2017 September 28, 2018 September 29, 2017 Service cost $ 200 $ 206 $ 618 $ 617 Interest cost on projected benefit obligation 706 748 2,115 2,245 Expected return on plan assets (970 ) (954 ) (2,918 ) (2,862 ) Net loss amortization 66 95 216 284 Net periodic benefit expense $ 2 $ 95 $ 31 $ 284

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 28, 2018
Debt Disclosure [Abstract]
Schedule of Composition of Debt	As of September 28, 2018 and December 31, 2017 the composition of our debt was as follows: September 28, December 31, 2018 2017 Term Loans $ 638,000 $ 713,000 8.875% Senior Notes due 2024 (the Notes) 300,000 300,000 Other 200 314 Total debt 938,200 1,013,314 Less: current portion of long-term debt (25,260 ) (26,947 ) Less: unamortized original issue discount costs and financing fees (41,083 ) (47,680 ) Long-term debt $ 871,857 $ 938,687

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 28, 2018
Fair Value Disclosures [Abstract]
Summary of Other Terms of Instruments	The other terms of these instruments are as follows: Contract received: Floating interest rate LIBOR (subject to minimum of 1.00%) Contract paid: Fixed interest rates 1.947% - 1.949% The other terms of these instruments are as follows: Contract received: Floating interest rate LIBOR (subject to minimum of 1.00%) Contract paid: Fixed interest rates 2.953% - 2.957%
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: September 28, December 31, Balance Sheet Classification Fair Value Hierarchy 2018 2017 Interest rate swap assets Other current assets Level 2 $ 1,478 $ — Interest rate swap assets Other assets Level 2 $ 3,387 $ 1,129 Interest rate swap liabilities Other current liabilities Level 2 $ (81 ) $ (477 )

Separate Financial Informatio_2

Separate Financial Information of Subsidiary Guarantor of Indebtedness (Tables)	9 Months Ended
	Sep. 28, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Unaudited Supplemental Condensed Consolidating Balance Sheet	UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 29,343 $ 37 $ 12,319 $ — $ 41,699 Accounts receivables, net — 65,807 2,324 7,774 — 75,905 Unbilled receivables — 239,721 4,338 11,400 — 255,459 Intercompany receivables — — 8,693 12,496 (21,189 ) — Other current assets — 16,962 — 1,628 — 18,590 Total current assets — 351,833 15,392 45,617 (21,189 ) 391,653 Property, plant and equipment, net — 49,445 — 47 — 49,492 Goodwill — 1,071,371 — — — 1,071,371 Identifiable intangible assets, net — 337,047 — — — 337,047 Deferred tax assets — 109,464 — — — 109,464 Investment in subsidiaries 707,789 47,578 33,858 — (789,225 ) — Other assets — 5,741 45 — — 5,786 Total assets $ 707,789 $ 1,972,479 $ 49,295 $ 45,664 $ (810,414 ) $ 1,964,813 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 25,260 $ — $ — $ — $ 25,260 Accounts payable, trade — 44,848 — 52 — 44,900 Intercompany payable — 21,189 — — (21,189 ) — Accrued employment costs — 87,393 1,717 10,194 — 99,304 Accrued expenses — 79,511 — 255 — 79,766 Advance payments and billings in excess of costs incurred — 26,261 — — — 26,261 Income tax liabilities — 180 — 172 352 Other current liabilities — 15,124 — 1,133 16,257 Total current liabilities — 299,766 1,717 11,806 (21,189 ) 292,100 Long-term debt — 871,857 — — — 871,857 Income tax liabilities — 33,080 — — — 33,080 Other liabilities — 59,987 — — — 59,987 Total liabilities — 1,264,690 1,717 11,806 (21,189 ) 1,257,024 Shareholders' equity 707,789 707,789 47,578 33,858 (789,225 ) 707,789 Total liabilities and equity $ 707,789 $ 1,972,479 $ 49,295 $ 45,664 $ (810,414 ) $ 1,964,813 SUPPLEMENTAL CONDENSED CONSOLIDATING BALANCE SHEET AS OF DECEMBER 31, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Assets: Current assets: Cash and cash equivalents $ — $ 31,966 $ 36 $ 9,888 $ — $ 41,890 Accounts receivables, net — 98,125 3,909 6,066 — 108,100 Unbilled receivables — 202,922 5,653 14,419 — 222,994 Intercompany receivables — — 28,069 7,738 (35,807 ) — Other current assets — 17,300 (4 ) 2,385 — 19,681 Total current assets — 350,313 37,663 40,496 (35,807 ) 392,665 Property, plant and equipment, net — 43,933 — 73 — 44,006 Goodwill — 1,071,371 — — — 1,071,371 Identifiable intangible assets, net — 361,410 — — — 361,410 Deferred tax assets — 150,535 — — — 150,535 Investment in subsidiaries 676,105 67,623 31,876 — (775,604 ) — Other assets — 5,976 45 — — 6,021 Total assets $ 676,105 $ 2,051,161 $ 69,584 $ 40,569 $ (811,411 ) $ 2,026,008 Liabilities and Equity: Current liabilities: Current portion of long-term debt $ — $ 26,947 $ — $ — $ — $ 26,947 Accounts payable, trade — 52,826 — 128 — 52,954 Intercompany payable — 35,807 — — (35,807 ) — Accrued employment costs — 68,622 1,961 6,962 — 77,545 Accrued expenses — 74,657 — 199 — 74,856 Advance payments and billings in excess of costs incurred — 30,380 — — — 30,380 Income tax liabilities — 320 — 228 548 Other current liabilities — 25,512 — 1,176 26,688 Total current liabilities — 315,071 1,961 8,693 (35,807 ) 289,918 Long-term debt — 938,687 — — — 938,687 Income tax liabilities — 62,219 — — — 62,219 Other liabilities — 59,079 — — — 59,079 Total liabilities — 1,375,056 1,961 8,693 (35,807 ) 1,349,903 Shareholders' equity 676,105 676,105 67,623 31,876 (775,604 ) 676,105 Total liabilities and equity $ 676,105 $ 2,051,161 $ 69,584 $ 40,569 $ (811,411 ) $ 2,026,008
Unaudited Supplemental Condensed Consolidating Statement of Operations and Comprehensive Income (Loss)	UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE THREE MONTHS ENDED SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 432,824 $ 2,650 $ 35,733 $ — $ 471,207 Costs and expenses Cost of revenue — 358,546 9,548 32,380 — 400,474 Selling, general and administrative expenses — 42,171 779 975 — 43,925 Total costs and expenses — 400,717 10,327 33,355 — 444,399 Operating income (loss) — 32,107 (7,677 ) 2,378 — 26,808 Interest expense, net — 16,981 — — — 16,981 Other expenses (income), net — (228 ) — 37 — (191 ) Income (loss) in equity investments in subsidiaries 4,282 (6,471 ) 1,206 — 983 — Income (loss) before income taxes 4,282 8,883 (6,471 ) 2,341 983 10,018 Provision for income taxes — 4,601 — — — 4,601 Net income (loss) 4,282 4,282 (6,471 ) 2,341 983 5,417 Less: Net income attributable to non-controlling interest — — — 1,135 — 1,135 Net income (loss) attributable to Engility $ 4,282 $ 4,282 $ (6,471 ) $ 1,206 $ 983 $ 4,282 Net income (loss) $ 4,282 $ 4,282 $ (6,471 ) $ 2,341 $ 983 $ 5,417 Other comprehensive income — 561 — — — 561 Comprehensive income (loss) 4,282 4,843 (6,471 ) 2,341 983 5,978 Less: Net income attributable to non-controlling interest — — — 1,135 — 1,135 Comprehensive income (loss) attributable to Engility $ 4,282 $ 4,843 $ (6,471 ) $ 1,206 $ 983 $ 4,843 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE THREE MONTHS ENDED SEPTEMBER 29, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 444,689 $ 7,771 $ 34,684 $ — $ 487,144 Costs and expenses Cost of revenue — 372,333 13,530 31,718 — 417,581 Selling, general and administrative expenses — 31,502 774 1,143 — 33,419 Total costs and expenses — 403,835 14,304 32,861 — 451,000 Operating income (loss) — 40,854 (6,533 ) 1,823 — 36,144 Interest expense, net — 19,739 — — — 19,739 Other expenses (income), net — (118 ) (1 ) 57 — (62 ) Income (loss) in equity investments in subsidiaries 9,805 (5,817 ) 715 — (4,703 ) — Income (loss) before income taxes 9,805 15,416 (5,817 ) 1,766 (4,703 ) 16,467 Provision for income taxes — 5,611 — — — 5,611 Net income (loss) 9,805 9,805 (5,817 ) 1,766 (4,703 ) 10,856 Less: Net income attributable to non-controlling interest — — — 1,051 — 1,051 Net income (loss) attributable to Engility $ 9,805 $ 9,805 $ (5,817 ) $ 715 $ (4,703 ) $ 9,805 Net income (loss) $ 9,805 $ 9,805 $ (5,817 ) $ 1,766 $ (4,703 ) $ 10,856 Other comprehensive loss — (55 ) — — — (55 ) Comprehensive income (loss) 9,805 9,750 (5,817 ) 1,766 (4,703 ) 10,801 Less: Net income attributable to non-controlling interest — — — 1,051 — 1,051 Comprehensive income (loss) attributable to Engility $ 9,805 $ 9,750 $ (5,817 ) $ 715 $ (4,703 ) $ 9,750 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE NINE MONTHS ENDED SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,312,973 $ 14,093 $ 109,215 $ — $ 1,436,281 Costs and expenses Cost of revenue — 1,091,600 34,867 99,195 — 1,225,662 Selling, general and administrative expenses — 114,762 2,617 3,432 — 120,811 Total costs and expenses — 1,206,362 37,484 102,627 — 1,346,473 Operating income (loss) — 106,611 (23,391 ) 6,588 — 89,808 Interest expense, net — 53,520 — — — 53,520 Other expenses (income), net — (620 ) — 179 — (441 ) Income (loss) in equity investments in subsidiaries 22,698 (20,045 ) 3,346 — (5,999 ) — Income (loss) before income taxes 22,698 33,666 (20,045 ) 6,409 (5,999 ) 36,729 Provision for income taxes — 10,968 — — — 10,968 Net income (loss) 22,698 22,698 (20,045 ) 6,409 (5,999 ) 25,761 Less: Net income attributable to non-controlling interest — — — 3,063 — 3,063 Net income (loss) attributable to Engility $ 22,698 $ 22,698 $ (20,045 ) $ 3,346 $ (5,999 ) $ 22,698 Net income (loss) $ 22,698 $ 22,698 $ (20,045 ) $ 6,409 $ (5,999 ) $ 25,761 Other comprehensive income — 2,948 — — — 2,948 Comprehensive income (loss) 22,698 25,646 (20,045 ) 6,409 (5,999 ) 28,709 Less: Net income attributable to non-controlling interest — — — 3,063 — 3,063 Comprehensive income (loss) attributable to Engility $ 22,698 $ 25,646 $ (20,045 ) $ 3,346 $ (5,999 ) $ 25,646 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) FOR THE NINE MONTHS ENDED SEPTEMBER 29, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Revenue $ — $ 1,335,395 $ 24,165 $ 107,470 $ — $ 1,467,030 Costs and expenses Cost of revenue — 1,117,184 41,527 96,892 — 1,255,603 Selling, general and administrative expenses — 102,064 2,465 3,107 — 107,636 Total costs and expenses — 1,219,248 43,992 99,999 — 1,363,239 Operating income (loss) — 116,147 (19,827 ) 7,471 — 103,791 Interest expense, net — 59,189 — — — 59,189 Other expenses (income), net — (352 ) (3 ) 234 — (121 ) Income (loss) in equity investments in subsidiaries 24,369 (16,270 ) 3,554 — (11,653 ) — Income (loss) before income taxes 24,369 41,040 (16,270 ) 7,237 (11,653 ) 44,723 Provision for income taxes — 16,671 — — — 16,671 Net income (loss) 24,369 24,369 (16,270 ) 7,237 (11,653 ) 28,052 Less: Net income attributable to non-controlling interest — — — 3,683 — 3,683 Net income (loss) attributable to Engility $ 24,369 $ 24,369 $ (16,270 ) $ 3,554 $ (11,653 ) $ 24,369 Net income (loss) $ 24,369 $ 24,369 $ (16,270 ) $ 7,237 $ (11,653 ) $ 28,052 Other comprehensive loss — (639 ) — — — (639 ) Comprehensive income (loss) 24,369 23,730 (16,270 ) 7,237 (11,653 ) 27,413 Less: Net income attributable to non-controlling interest — — — 3,683 — 3,683 Comprehensive income (loss) attributable to Engility $ 24,369 $ 23,730 $ (16,270 ) $ 3,554 $ (11,653 ) $ 23,730
Unaudited Supplemental Condensed Consolidating Statement of Cash Flows	UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE NINE MONTHS ENDED SEPTEMBER 28, 2018 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by (used in) operating activities $ — $ 102,504 $ (19,375 ) $ 11,616 $ — $ 94,745 Investing activities: Payments from sale of business — (1,900 ) — — — (1,900 ) Capital expenditures — (11,404 ) — — — (11,404 ) Net cash used in investing activities — (13,304 ) — — — (13,304 ) Financing activities: Repayment of long-term debt — (75,115 ) — — — (75,115 ) Gross borrowings from revolving credit facility — 167,000 — — — 167,000 Repayments of revolving credit facility — (167,000 ) — — — (167,000 ) Debt issuance costs — (45 ) — — — (45 ) Payment of employee withholding taxes on share-based compensation (2,045 ) — — — — (2,045 ) Distributions to non-controlling interest member — — — (4,427 ) — (4,427 ) Due (to) from subsidiaries 2,045 (16,663 ) 19,376 (4,758 ) — — Net cash provided by (used in) financing activities — (91,823 ) 19,376 (9,185 ) — (81,632 ) Net change in cash and cash equivalents — (2,623 ) 1 2,431 — (191 ) Cash and cash equivalents, beginning of period — 31,966 36 9,888 — 41,890 Cash and cash equivalents, end of period $ — $ 29,343 $ 37 $ 12,319 $ — $ 41,699 UNAUDITED SUPPLEMENTAL CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE NINE MONTHS ENDED SEPTEMBER 29, 2017 Engility Holdings, Inc. Engility Corporation Subsidiary Guarantors Subsidiary Non- guarantors Consolidating Adjustments Consolidated Operating activities: Net cash provided by operating activities $ — $ 72,527 $ (4,099 ) $ 10,327 $ — $ 78,755 Investing activities: Proceeds from sale of business, net of amount placed in escrow — 22,349 — — — 22,349 Proceeds from sale of property, plant and equipment — 2,902 — — — 2,902 Capital expenditures — (5,810 ) — — — (5,810 ) Net cash provided by investing activities — 19,441 — — — 19,441 Financing activities: Repayment of long-term debt — (86,410 ) — — — (86,410 ) Gross borrowings from revolving credit facility — 270,000 — — — 270,000 Repayments of revolving credit facility — (270,000 ) — — — (270,000 ) Payment of employee withholding taxes on share-based compensation (1,501 ) — — — — (1,501 ) Dividends paid (407 ) — — — — (407 ) Distributions to non-controlling interest member — — — (6,136 ) — (6,136 ) Due (to) from subsidiaries 1,908 (222 ) 3,840 (5,526 ) — — Net cash provided by (used in) financing activities — (86,632 ) 3,840 (11,662 ) — (94,454 ) Net change in cash and cash equivalents — 5,336 (259 ) (1,335 ) — 3,742 Cash and cash equivalents, beginning of period — 31,124 385 16,727 — 48,236 Cash and cash equivalents, end of period $ — $ 36,460 $ 126 $ 15,392 $ — $ 51,978

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands	Sep. 09, 2018	Jan. 06, 2017	Sep. 28, 2018	Sep. 29, 2017	Mar. 31, 2017	Sep. 28, 2018	Sep. 29, 2017	Jan. 01, 2018	Dec. 31, 2017
Basis of Presentation [Line Items]
Unbilled receivables restructuring costs incurred			$ 6,000			$ 6,000			$ 9,000
Anti-dilutive securities			0	0		71	10,949
Working capital adjustments finalized				$ 2,000
Long-term assets held for sale					$ 2,000
Accumulated depreciation					1,000
Gain on sale of long-term assets						$ (69)	$ 306
Selling, General and Administrative Expenses [Member]
Basis of Presentation [Line Items]
Gain on sale of long-term assets					1,000
International Resources Group Ltd. [Member]
Basis of Presentation [Line Items]
Initial purchase price		$ 25,000
Cash on hand adjustment purchase price				$ 1,000
Indemnity escrow					$ 2,000
Accounting Standards Update 2014-09 [Member] | Accumulated Deficit [Member]
Basis of Presentation [Line Items]
Cumulative effect of change in accumulated deficit								$ 300
Merger Agreement [Member]
Basis of Presentation [Line Items]
Common stock exchange ratio	450
Transaction costs associated with pending merger	$ 5,000
Engility Corporation [Member]
Basis of Presentation [Line Items]
Capital stock owning percentage by parent			100.00%			100.00%
Forfeiture Support Associates LLC [Member]
Basis of Presentation [Line Items]
Non-controlling equity interest ownership percentage			50.10%			50.10%

Basis of Presentation - Calcula

Basis of Presentation - Calculation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Net income attributable to Engility	$ 4,282	$ 9,805	$ 22,698	$ 24,369
Weighted average number of shares outstanding – Basic	36,968	36,809	36,928	36,831
Dilutive effect of share-based compensation outstanding after application of the treasury stock method	814	539	809	523
Weighted average number of shares outstanding – Diluted	37,782	37,348	37,737	37,354
Earnings per share attributable to Engility
Basic	$ 0.12	$ 0.27	$ 0.61	$ 0.66
Diluted	$ 0.11	$ 0.26	$ 0.60	$ 0.65

New Accounting Pronouncements -

New Accounting Pronouncements - Additional Information (Details) $ in Millions	Jan. 01, 2018USD ($)
Accounting Standards Update 2018-02 [Member] | Accumulated Deficit [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative effect of change in equity	$ 1
Accounting Standards Update 2018-02 [Member] | Accumulated Other Comprehensive Loss [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative effect of change in equity	(1)
Accounting Standards Update 2014-09 [Member] | Accumulated Deficit [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative effect of change in accumulated deficit	$ 0.3

New Accounting Pronouncements_2

New Accounting Pronouncements - Summary of Effect Adopting ASC 606 on Unaudited Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 28, 2018	Jan. 01, 2018	Dec. 31, 2017
Current assets:
Accounts receivables, net	$ 75,905		$ 108,100
Unbilled receivables	255,459		222,994
Other current assets	18,590		19,681
Deferred tax assets	109,464		150,535
Current liabilities:
Advance payments and billings in excess of costs incurred	26,261		30,380
Equity:
Accumulated deficit	(552,151)		$ (576,019)
Accounting Standards Update 2014-09 [Member] | Balances Under ASC 605 [Member]
Current assets:
Accounts receivables, net	75,905
Unbilled receivables	230,556
Other current assets	42,144
Deferred tax assets	109,816
Current liabilities:
Advance payments and billings in excess of costs incurred	26,261
Equity:
Accumulated deficit	(553,148)
Accounting Standards Update 2014-09 [Member] | Impact from Adoption of ASC 606 [Member]
Current assets:
Unbilled receivables	19,420	$ 5,483
Other current assets	(18,523)	(5,031)
Deferred tax assets	(234)	(118)
Equity:
Accumulated deficit	$ 663	$ 334

New Accounting Pronouncements_3

New Accounting Pronouncements - Summary of Effect Adopting ASC 606 on Unaudited Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 471,207		$ 1,436,281
Cost of revenue	400,474	$ 417,581	1,225,662	$ 1,255,603
Operating income	26,808	36,144	89,808	103,791
Provision for income taxes	4,601	5,611	10,968	16,671
Net income attributable to Engility	4,282	$ 9,805	22,698	$ 24,369
Accounting Standards Update 2014-09 [Member] | Balances Under ASC 605 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	467,868		1,416,861
Cost of revenue	397,587		1,207,139
Operating income	26,356		88,911
Provision for income taxes	4,483		10,734
Net income attributable to Engility	3,948		22,035
Accounting Standards Update 2014-09 [Member] | Impact from Adoption of ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	3,339		19,420
Cost of revenue	2,887		18,523
Operating income	452		897
Provision for income taxes	118		234
Net income attributable to Engility	$ 334		$ 663

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Details) - USD ($) $ in Thousands	Jan. 01, 2018	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Increased in revenue		$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Accounting Standards Update 2014-09 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Decrease to the opening balance of accumulated deficit, ASC 606	$ 300
Effect of Adoption of ASC 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Increased in revenue		2,000	4,000	6,000	9,000
Increased operating income		2,000	4,000	6,000	9,000
Amount related to favorable performance on contract award fees		1,000	$ 1,000	2,000	$ 2,000
Effect of Adoption of ASC 606 [Member] | Accounting Standards Update 2014-09 [Member] | Transferred over Time [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Increase in revenue recognition		3,000		19,000
Balances Without Adoption of ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Balance for contract assets	228,000
Balance for contract liabilities	$ 30,000
Revenue included in advance payments in excess of costs		$ 3,000		$ 14,000

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Aggregate Amount of Transaction Price Allocated to Remaining Performance Obligations (Details) $ in Thousands	Sep. 28, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-09-28
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total remaining performance obligation	$ 411,223
Remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total remaining performance obligation	$ 560,786
Remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total remaining performance obligation	$ 71,343
Remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total remaining performance obligation	$ 35,049
Remaining performance obligation, expected timing of satisfaction, period
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: (nil)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Total remaining performance obligation	$ 1,078,401
Remaining performance obligation, expected timing of satisfaction, period

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Summary of Revenue Disaggregated by Several Categories (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Disaggregation Of Revenue [Line Items]
Revenue	$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Revenue by Contract Type [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Revenue by Contract Type [Member] | Sales Revenue, Net [Member] | Contract Type Concentration Risk [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Revenue by Contract Type [Member] | Cost Plus [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 295,509	$ 314,880	$ 921,423	$ 924,524
Revenue by Contract Type [Member] | Cost Plus [Member] | Sales Revenue, Net [Member] | Contract Type Concentration Risk [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	62.70%	64.60%	64.20%	63.00%
Revenue by Contract Type [Member] | Time and Material [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 93,320	$ 91,563	$ 263,089	$ 284,186
Revenue by Contract Type [Member] | Time and Material [Member] | Sales Revenue, Net [Member] | Contract Type Concentration Risk [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	19.80%	18.80%	18.30%	19.40%
Revenue by Contract Type [Member] | Fixed Price [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 82,378	$ 80,701	$ 251,769	$ 258,320
Revenue by Contract Type [Member] | Fixed Price [Member] | Sales Revenue, Net [Member] | Contract Type Concentration Risk [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	17.50%	16.60%	17.50%	17.60%
Revenue by Customer Market [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Revenue by Customer Market [Member] | DoD [Member]
Disaggregation Of Revenue [Line Items]
Revenue	176,131	193,433	557,168	590,571
Revenue by Customer Market [Member] | Federal Civilian [Member]
Disaggregation Of Revenue [Line Items]
Revenue	114,232	111,905	334,972	342,192
Revenue by Customer Market [Member] | Intelligence [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 180,844	$ 181,806	$ 544,141	$ 534,267
Revenue by Customer Market [Member] | Sales Revenue, Net [Member] | Customer Market Concentration Risk [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Revenue by Customer Market [Member] | Sales Revenue, Net [Member] | Customer Market Concentration Risk [Member] | DoD [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	37.40%	39.70%	38.80%	40.30%
Revenue by Customer Market [Member] | Sales Revenue, Net [Member] | Customer Market Concentration Risk [Member] | Federal Civilian [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	24.20%	23.00%	23.30%	23.30%
Revenue by Customer Market [Member] | Sales Revenue, Net [Member] | Customer Market Concentration Risk [Member] | Intelligence [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	38.40%	37.30%	37.90%	36.40%
Revenue by Prime and Subcontractor [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Revenue by Prime and Subcontractor [Member] | Prime [Member]
Disaggregation Of Revenue [Line Items]
Revenue	388,782	407,110	1,182,758	1,211,225
Revenue by Prime and Subcontractor [Member] | Subcontractor [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 82,425	$ 80,034	$ 253,523	$ 255,805
Revenue by Prime and Subcontractor [Member] | Sales Revenue, Net [Member] | Prime and Subcontractor Concentration Risk [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Revenue by Prime and Subcontractor [Member] | Sales Revenue, Net [Member] | Prime and Subcontractor Concentration Risk [Member] | Prime [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	82.50%	83.60%	82.30%	82.60%
Revenue by Prime and Subcontractor [Member] | Sales Revenue, Net [Member] | Prime and Subcontractor Concentration Risk [Member] | Subcontractor [Member]
Disaggregation Of Revenue [Line Items]
Revenue, concentration risk percentage	17.50%	16.40%	17.70%	17.40%

Accounts Receivables - Componen

Accounts Receivables - Components of Account Receivables (Details) - USD ($) $ in Thousands	Sep. 28, 2018	Dec. 31, 2017
Accounts Receivable Net Current [Abstract]
Account receivables	$ 86,332	$ 119,506
Allowance for doubtful accounts	(10,427)	(11,406)
Account receivables, net	$ 75,905	$ 108,100

Identifiable Intangible Asset_2

Identifiable Intangible Assets - Information on Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 28, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 552,229	$ 552,229
Accumulated Amortization	215,182	190,819
Net Carrying Amount	$ 337,047	361,410
Customer Contractual Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	17 years
Gross Carrying Amount	$ 545,229	545,229
Accumulated Amortization	213,510	189,497
Net Carrying Amount	$ 331,719	355,732
Technology [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	15 years
Gross Carrying Amount	$ 7,000	7,000
Accumulated Amortization	1,672	1,322
Net Carrying Amount	$ 5,328	$ 5,678

Identifiable Intangible Asset_3

Identifiable Intangible Assets - Amortization Expense Recorded for Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 8,120	$ 8,121	$ 24,363	$ 24,363

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - $ / shares	9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Description	if the Merger Agreement is not terminated on or prior to December 21, 2018, certain performance units and restricted stock units will immediately vest and settle on that date. As each of the modifications above is conditioned upon events outside of the Company’s control, unrecognized compensation expense associated with these performance units and restricted stock units will be recognized when management concludes that the conditions for the modification are probable of being met
Employees [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in the period	201,571	189,351
Shares granted at maximum performance level	604,713	568,053
Weighted average share price (USD per share)	$ 24.60	$ 30.54
Performance period	3 years	3 years
Percent of the target grant amount	100.00%	100.00%
Employees [Member] | Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount	0.00%	0.00%
Employees [Member] | Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of the target grant amount	300.00%	300.00%
Employees [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in the period	242,883	220,194
Weighted average share price (USD per share)	$ 24.81	$ 30.44
Vesting period	3 years	3 years
Employees [Member] | Restricted Stock Units (RSUs) [Member] | Period One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	1,098	775
Employees [Member] | Restricted Stock Units (RSUs) [Member] | Period Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	11,700	12,137
Employees [Member] | Restricted Stock Units (RSUs) [Member] | Over Period One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	230,085	207,282
Non-management Members Of The Board Of Directors [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in the period	31,768	29,431
Weighted average share price (USD per share)	$ 30.22	$ 28.25

Defined Benefit Plans - Compone

Defined Benefit Plans - Components of Net Periodic Benefit Costs for Defined Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Postemployment Benefits [Abstract]
Service cost	$ 200	$ 206	$ 618	$ 617
Interest cost on projected benefit obligation	706	748	2,115	2,245
Expected return on plan assets	(970)	(954)	(2,918)	(2,862)
Net loss amortization	66	95	216	284
Net periodic benefit expense	$ 2	$ 95	$ 31	$ 284

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	Mar. 21, 2018	Aug. 14, 2017	Aug. 12, 2016	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017	Mar. 22, 2018
Debt Instrument [Line Items]
Repayment of term loan debt						$ 167,000,000	$ 270,000,000
Average outstanding loan amount				$ 966,000,000	$ 1,060,000,000	$ 988,000,000	$ 1,088,000,000
Interest rate during period				6.05%	5.85%	6.05%	5.97%
2016 Credit Facility [Member]
Debt Instrument [Line Items]
Secured debt To EBITDA ratio			5.625%
Consolidated net leverage ratio				305.00%		305.00%
Current borrowing capacity				$ 188,000,000		$ 188,000,000
Repayment of term loan debt						75,000,000
2016 Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit, amount outstanding				$ 2,000,000		2,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Early termination penalty						2,000,000
Term B1 Loan [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility		$ 185,000,000
Term B2 Loan [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Total credit facility		$ 579,000,000
Reallocation of existing term loan	$ 75,000,000
Prepayment of term loan debt						$ 56,000,000
Senior Secured Revolving Loan Facility [Member]
Debt Instrument [Line Items]
Additional borrowing amount								$ 25,000,000
Base Rate Loans [Member] | Term B1 Loan [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%	1.75%
Base Rate Loans [Member] | Term B2 Loan [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%	2.25%
Eurocurrency Loans [Member] | Term B1 Loan [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%	2.75%
Eurocurrency Loans [Member] | Term B2 Loan [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%	3.25%

Debt - Schedule of Composition

Debt - Schedule of Composition of Debt (Details) - USD ($) $ in Thousands	Sep. 28, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 938,200	$ 1,013,314
Less: current portion of long-term debt	(25,260)	(26,947)
Less: unamortized original issue discount costs and financing fees	(41,083)	(47,680)
Long-term debt	871,857	938,687
8.875% Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Total debt	300,000	300,000
Term Loan [Member]
Debt Instrument [Line Items]
Total debt	638,000	713,000
Other [Member]
Debt Instrument [Line Items]
Total debt	$ 200	$ 314

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 29, 2018	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, expiration date	Jul. 29, 2022	Dec. 31, 2020
Interest Rate Swap Effective December 29, 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, notional amount		$ 281
Interest Rate Swap Effective April 30, 2019 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, notional amount	$ 167

Fair Value Measurements - Other

Fair Value Measurements - Other Terms of Instruments (Details) - Interest Rate Swap [Member]	Jun. 29, 2018	Mar. 31, 2017
London Interbank Offered Rate (LIBOR) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, swaption interest rate	1.00%	1.00%
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, fixed interest rate	2.953%	1.947%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, fixed interest rate	2.957%	1.949%

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Liabilities Measured on a Recurring Basis (Details) - Recurring [Member] - Level 2 [Member] - USD ($) $ in Thousands	Sep. 28, 2018	Dec. 31, 2017
Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap assets	$ 1,478
Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap assets	3,387	$ 1,129
Other Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap liabilities	$ (81)	$ (477)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 4,601	$ 5,611	$ 10,968	$ 16,671
Effective income tax rate	45.90%	34.10%	29.90%	37.30%
Federal income tax rate			21.00%		35.00%

Separate Financial Informatio_3

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Additional Information (Details)	Sep. 28, 2018
Guarantees [Member]
Guarantee Obligations [Line Items]
Percentage of voting stock outstanding in subsidiary guarantors	100.00%

Separate Financial Informatio_4

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Unaudited Supplemental Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 28, 2018	Dec. 31, 2017	Mar. 31, 2017
Current assets:
Cash and cash equivalents	$ 41,699	$ 41,890
Accounts receivables, net	75,905	108,100
Unbilled receivables	255,459	222,994
Assets held for sale, current			$ 2,000
Other current assets	18,590	19,681
Total current assets	391,653	392,665
Property, plant and equipment, net	49,492	44,006
Goodwill	1,071,371	1,071,371
Identifiable intangible assets, net	337,047	361,410
Deferred tax assets	109,464	150,535
Other assets	5,786	6,021
Total assets	1,964,813	2,026,008
Current liabilities:
Current portion of long-term debt	25,260	26,947
Accounts payable, trade	44,900	52,954
Accrued employment costs	99,304	77,545
Accrued expenses	79,766	74,856
Advance payments and billings in excess of costs incurred	26,261	30,380
Income tax liabilities	352	548
Other current liabilities	16,257	26,688
Total current liabilities	292,100	289,918
Long-term debt	871,857	938,687
Income tax liabilities	33,080	62,219
Other liabilities	59,987	59,079
Total liabilities	1,257,024	1,349,903
Shareholders' equity	707,789	676,105
Total liabilities and equity	1,964,813	2,026,008
Engility Holdings, Inc. [Member]
Current assets:
Investment in subsidiaries	707,789	676,105
Total assets	707,789	676,105
Current liabilities:
Shareholders' equity	707,789	676,105
Total liabilities and equity	707,789	676,105
Engility Corporation [Member]
Current assets:
Cash and cash equivalents	29,343	31,966
Accounts receivables, net	65,807	98,125
Unbilled receivables	239,721	202,922
Other current assets	16,962	17,300
Total current assets	351,833	350,313
Property, plant and equipment, net	49,445	43,933
Goodwill	1,071,371	1,071,371
Identifiable intangible assets, net	337,047	361,410
Deferred tax assets	109,464	150,535
Investment in subsidiaries	47,578	67,623
Other assets	5,741	5,976
Total assets	1,972,479	2,051,161
Current liabilities:
Current portion of long-term debt	25,260	26,947
Accounts payable, trade	44,848	52,826
Intercompany payable	21,189	35,807
Accrued employment costs	87,393	68,622
Accrued expenses	79,511	74,657
Advance payments and billings in excess of costs incurred	26,261	30,380
Income tax liabilities	180	320
Other current liabilities	15,124	25,512
Total current liabilities	299,766	315,071
Long-term debt	871,857	938,687
Income tax liabilities	33,080	62,219
Other liabilities	59,987	59,079
Total liabilities	1,264,690	1,375,056
Shareholders' equity	707,789	676,105
Total liabilities and equity	1,972,479	2,051,161
Subsidiary Guarantors [Member]
Current assets:
Cash and cash equivalents	37	36
Accounts receivables, net	2,324	3,909
Unbilled receivables	4,338	5,653
Intercompany receivables	8,693	28,069
Other current assets		(4)
Total current assets	15,392	37,663
Investment in subsidiaries	33,858	31,876
Other assets	45	45
Total assets	49,295	69,584
Current liabilities:
Accrued employment costs	1,717	1,961
Total current liabilities	1,717	1,961
Total liabilities	1,717	1,961
Shareholders' equity	47,578	67,623
Total liabilities and equity	49,295	69,584
Subsidiary Non-guarantors [Member]
Current assets:
Cash and cash equivalents	12,319	9,888
Accounts receivables, net	7,774	6,066
Unbilled receivables	11,400	14,419
Intercompany receivables	12,496	7,738
Other current assets	1,628	2,385
Total current assets	45,617	40,496
Property, plant and equipment, net	47	73
Total assets	45,664	40,569
Current liabilities:
Accounts payable, trade	52	128
Accrued employment costs	10,194	6,962
Accrued expenses	255	199
Income tax liabilities	172	228
Other current liabilities	1,133	1,176
Total current liabilities	11,806	8,693
Total liabilities	11,806	8,693
Shareholders' equity	33,858	31,876
Total liabilities and equity	45,664	40,569
Consolidating Adjustments [Member]
Current assets:
Intercompany receivables	(21,189)	(35,807)
Total current assets	(21,189)	(35,807)
Investment in subsidiaries	(789,225)	(775,604)
Total assets	(810,414)	(811,411)
Current liabilities:
Intercompany payable	(21,189)	(35,807)
Total current liabilities	(21,189)	(35,807)
Total liabilities	(21,189)	(35,807)
Shareholders' equity	(789,225)	(775,604)
Total liabilities and equity	$ (810,414)	$ (811,411)

Separate Financial Informatio_5

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Unaudited Supplemental Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Revenue	$ 471,207	$ 487,144	$ 1,436,281	$ 1,467,030
Costs and expenses
Cost of revenue	400,474	417,581	1,225,662	1,255,603
Selling, general and administrative expenses	43,925	33,419	120,811	107,636
Total costs and expenses	444,399	451,000	1,346,473	1,363,239
Operating income	26,808	36,144	89,808	103,791
Interest expense, net	16,981	19,739	53,520	59,189
Other income, net	(191)	(62)	(441)	(121)
Income before provision for income taxes	10,018	16,467	36,729	44,723
Provision for income taxes	4,601	5,611	10,968	16,671
Net income	5,417	10,856	25,761	28,052
Less: Net income attributable to non-controlling interest	1,135	1,051	3,063	3,683
Net income attributable to Engility	4,282	9,805	22,698	24,369
Net income (loss)	5,417	10,856	25,761	28,052
Other Comprehensive Income (Loss)	561	(55)	2,948	(639)
Comprehensive income	5,978	10,801	28,709	27,413
Less: Net income attributable to non-controlling interest	1,135	1,051	3,063	3,683
Comprehensive income attributable to Engility	4,843	9,750	25,646	23,730
Engility Holdings, Inc. [Member]
Costs and expenses
Income (loss) in equity investments in subsidiaries	4,282	9,805	22,698	24,369
Income before provision for income taxes	4,282	9,805	22,698	24,369
Net income	4,282	9,805	22,698	24,369
Net income attributable to Engility	4,282	9,805	22,698	24,369
Net income (loss)	4,282	9,805	22,698	24,369
Comprehensive income	4,282	9,805	22,698	24,369
Comprehensive income attributable to Engility	4,282	9,805	22,698	24,369
Engility Corporation [Member]
Revenue	432,824	444,689	1,312,973	1,335,395
Costs and expenses
Cost of revenue	358,546	372,333	1,091,600	1,117,184
Selling, general and administrative expenses	42,171	31,502	114,762	102,064
Total costs and expenses	400,717	403,835	1,206,362	1,219,248
Operating income	32,107	40,854	106,611	116,147
Interest expense, net	16,981	19,739	53,520	59,189
Other income, net	(228)	(118)	(620)	(352)
Income (loss) in equity investments in subsidiaries	(6,471)	(5,817)	(20,045)	(16,270)
Income before provision for income taxes	8,883	15,416	33,666	41,040
Provision for income taxes	4,601	5,611	10,968	16,671
Net income	4,282	9,805	22,698	24,369
Net income attributable to Engility	4,282	9,805	22,698	24,369
Net income (loss)	4,282	9,805	22,698	24,369
Other Comprehensive Income (Loss)	561	(55)	2,948	(639)
Comprehensive income	4,843	9,750	25,646	23,730
Comprehensive income attributable to Engility	4,843	9,750	25,646	23,730
Subsidiary Guarantors [Member]
Revenue	2,650	7,771	14,093	24,165
Costs and expenses
Cost of revenue	9,548	13,530	34,867	41,527
Selling, general and administrative expenses	779	774	2,617	2,465
Total costs and expenses	10,327	14,304	37,484	43,992
Operating income	(7,677)	(6,533)	(23,391)	(19,827)
Other income, net		(1)		(3)
Income (loss) in equity investments in subsidiaries	1,206	715	3,346	3,554
Income before provision for income taxes	(6,471)	(5,817)	(20,045)	(16,270)
Net income	(6,471)	(5,817)	(20,045)	(16,270)
Net income attributable to Engility	(6,471)	(5,817)	(20,045)	(16,270)
Net income (loss)	(6,471)	(5,817)	(20,045)	(16,270)
Comprehensive income	(6,471)	(5,817)	(20,045)	(16,270)
Comprehensive income attributable to Engility	(6,471)	(5,817)	(20,045)	(16,270)
Subsidiary Non-guarantors [Member]
Revenue	35,733	34,684	109,215	107,470
Costs and expenses
Cost of revenue	32,380	31,718	99,195	96,892
Selling, general and administrative expenses	975	1,143	3,432	3,107
Total costs and expenses	33,355	32,861	102,627	99,999
Operating income	2,378	1,823	6,588	7,471
Other income, net	37	57	179	234
Income before provision for income taxes	2,341	1,766	6,409	7,237
Net income	2,341	1,766	6,409	7,237
Less: Net income attributable to non-controlling interest	1,135	1,051	3,063	3,683
Net income attributable to Engility	1,206	715	3,346	3,554
Net income (loss)	2,341	1,766	6,409	7,237
Comprehensive income	2,341	1,766	6,409	7,237
Less: Net income attributable to non-controlling interest	1,135	1,051	3,063	3,683
Comprehensive income attributable to Engility	1,206	715	3,346	3,554
Consolidating Adjustments [Member]
Costs and expenses
Income (loss) in equity investments in subsidiaries	983	(4,703)	(5,999)	(11,653)
Income before provision for income taxes	983	(4,703)	(5,999)	(11,653)
Net income	983	(4,703)	(5,999)	(11,653)
Net income attributable to Engility	983	(4,703)	(5,999)	(11,653)
Net income (loss)	983	(4,703)	(5,999)	(11,653)
Comprehensive income	983	(4,703)	(5,999)	(11,653)
Comprehensive income attributable to Engility	$ 983	$ (4,703)	$ (5,999)	$ (11,653)

Separate Financial Informatio_6

Separate Financial Information of Subsidiary Guarantor of Indebtedness - Unaudited Supplemental Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 28, 2018	Sep. 29, 2017
Operating activities:
Net cash provided by (used in) operating activities	$ 94,745	$ 78,755
Investing activities:
Proceeds (payments) from sale of business, net of amount placed in escrow	(1,900)	22,349
Proceeds from sale of property, plant and equipment		2,902
Capital expenditures	(11,404)	(5,810)
Net cash provided by (used in) investing activities	(13,304)	19,441
Financing activities:
Repayment of long-term debt	(75,115)	(86,410)
Gross borrowings from revolving credit facility	167,000	270,000
Gross repayments of revolving credit facility	(167,000)	(270,000)
Debt issuance costs	(45)
Payment of employee withholding taxes on share-based compensation	(2,045)	(1,501)
Dividends paid		(407)
Distributions to non-controlling interest member	(4,427)	(6,136)
Net cash used in financing activities	(81,632)	(94,454)
Net change in cash and cash equivalents	(191)	3,742
Cash and cash equivalents, beginning of period	41,890	48,236
Cash and cash equivalents, end of period	41,699	51,978
Engility Holdings, Inc. [Member]
Financing activities:
Payment of employee withholding taxes on share-based compensation	(2,045)	(1,501)
Dividends paid		(407)
Due (to) from subsidiaries	2,045	1,908
Engility Corporation [Member]
Operating activities:
Net cash provided by (used in) operating activities	102,504	72,527
Investing activities:
Proceeds (payments) from sale of business, net of amount placed in escrow	(1,900)	22,349
Proceeds from sale of property, plant and equipment		2,902
Capital expenditures	(11,404)	(5,810)
Net cash provided by (used in) investing activities	(13,304)	19,441
Financing activities:
Repayment of long-term debt	(75,115)	(86,410)
Gross borrowings from revolving credit facility	167,000	270,000
Gross repayments of revolving credit facility	(167,000)	(270,000)
Debt issuance costs	(45)
Due (to) from subsidiaries	(16,663)	(222)
Net cash used in financing activities	(91,823)	(86,632)
Net change in cash and cash equivalents	(2,623)	5,336
Cash and cash equivalents, beginning of period	31,966	31,124
Cash and cash equivalents, end of period	29,343	36,460
Subsidiary Guarantors [Member]
Operating activities:
Net cash provided by (used in) operating activities	(19,375)	(4,099)
Financing activities:
Due (to) from subsidiaries	19,376	3,840
Net cash used in financing activities	19,376	3,840
Net change in cash and cash equivalents	1	(259)
Cash and cash equivalents, beginning of period	36	385
Cash and cash equivalents, end of period	37	126
Subsidiary Non-guarantors [Member]
Operating activities:
Net cash provided by (used in) operating activities	11,616	10,327
Financing activities:
Distributions to non-controlling interest member	(4,427)	(6,136)
Due (to) from subsidiaries	(4,758)	(5,526)
Net cash used in financing activities	(9,185)	(11,662)
Net change in cash and cash equivalents	2,431	(1,335)
Cash and cash equivalents, beginning of period	9,888	16,727
Cash and cash equivalents, end of period	$ 12,319	$ 15,392