Mantech International (MANT) 10-K 22 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 20, 2019	Jun. 30, 2018
Entity Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	MANT
Entity Registrant Name	MANTECH INTERNATIONAL CORP
Entity Central Index Key	892,537
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Emerging Growth Company	false
Small Reporting Company	false
Entity Shell Company	false
Entity Public Float			$ 1,410
Class A Common Stock [Member]
Entity Information [Line Items]
Common Stock, Shares Outstanding		26,582,884
Common Stock, Class B
Entity Information [Line Items]
Common Stock, Shares Outstanding		13,188,045

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 5,294	$ 9,451
Receivables—net	405,378	311,410
Prepaid expenses	23,398	22,933
Other current assets	5,915	23,370
Total Current Assets	439,985	367,164
Goodwill	1,085,806	1,084,560
Other intangible assets—net	171,962	194,348
Property and equipment—net	51,427	46,082
Employee supplemental savings plan assets	30,501	33,555
Investments	11,830	11,843
Other assets	12,360	6,923
TOTAL ASSETS	1,803,871	1,744,475
LIABILITIES
Accounts payable and accrued expenses	126,066	122,405
Accrued salaries and related expenses	89,058	87,064
Contract liabilities	28,209	18,816
Total Current Liabilities	243,333	228,285
Long term debt	7,500	31,000
Deferred income taxes	108,956	97,194
Accrued retirement	30,999	34,517
Other long-term liabilities	11,889	10,505
TOTAL LIABILITIES	402,677	401,501
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY
Additional paid-in capital	506,970	492,030
Treasury stock	(9,158)	(9,158)
Retained earnings	903,084	860,027
Accumulated other comprehensive loss	(102)	(320)
TOTAL STOCKHOLDERS' EQUITY	1,401,194	1,342,974
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,803,871	1,744,475
Class A Common Stock [Member]
STOCKHOLDERS' EQUITY
Common stock	268	263
TOTAL STOCKHOLDERS' EQUITY	268	263
Common Stock, Class B
STOCKHOLDERS' EQUITY
Common stock	132	132
TOTAL STOCKHOLDERS' EQUITY	$ 132	$ 132

Consolidated Balance Sheets Par

Consolidated Balance Sheets Parenthetical - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Treasury Stock, Shares	244,113	244,113
Class A Common Stock [Member]
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	150,000,000	150,000,000
Common Stock, Shares Issued	26,817,513	26,285,773
Common Stock, Shares Outstanding	26,573,400	26,041,660
Common Stock, Class B
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Shares Issued	13,188,045	13,189,245
Common Stock, Shares Outstanding	13,188,045	13,189,245

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
REVENUES	$ 1,958,557	$ 1,717,018	$ 1,601,596
Cost of services	1,678,100	1,463,599	1,369,775
General and administrative expenses	167,715	155,225	140,858
OPERATING INCOME	112,742	98,194	90,963
Interest expense	(2,378)	(1,375)	(1,097)
Interest income	161	104	121
Other income, net	80	319	83
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND EQUITY METHOD INVESTMENTS	110,605	97,242	90,070
(Provision) benefit for income taxes	(28,530)	16,859	(33,786)
Equity in earnings of unconsolidated subsidiaries	22	40	107
NET INCOME	$ 82,097	$ 114,141	$ 56,391
Class A Common Stock [Member]
BASIC EARNINGS PER SHARE:
Basic earnings per share	$ 2.08	$ 2.94	$ 1.48
DILUTED EARNINGS PER SHARE:
Diluted earnings per share	2.06	2.91	1.47
Common Stock, Class B
BASIC EARNINGS PER SHARE:
Basic earnings per share	2.08	2.94	1.48
DILUTED EARNINGS PER SHARE:
Diluted earnings per share	$ 2.06	$ 2.91	$ 1.47

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 82,097	$ 114,141	$ 56,391
OTHER COMPREHENSIVE INCOME (LOSS):
Actuarial gain (loss) on defined benefit pension plans, net of tax	245	(84)	(29)
Translation adjustments, net of tax	(27)	(55)	(43)
Total other comprehensive income (loss)	218	(139)	(72)
COMPREHENSIVE INCOME	$ 82,315	$ 114,002	$ 56,319

Consolidated Statement of Chang

Consolidated Statement of Changes in Stockholders' Equity Statement - USD ($)	Total	Common Stock, Class A	Common Stock, Class B	Additional Paid-In Capital	Treasury Stock, at cost	Retained Earnings	Accumulated Other Comprehensive Loss
Stockholders' Equity		$ 247,000	$ 132,000	$ 438,168,000	$ (9,158,000)	$ 754,457,000	$ (109,000)
Stock option exercises		11,000		30,551,000
Stock-based compensation expense		0
Stock-based compensation expense				3,323,000
Payment consideration to tax authority on employees' behalf				0
Cumulative-effect adjustment for adoption of Accounting Standards Update 2016-09				0
Tax deficiency from the exercise of stock options	$ 100,000			(136,000)
Net income	56,391,000					56,391,000
Dividends						(32,138,000)
Cumulative-effect adjustment for adoption of Accounting Standards Update 2014-09						0
Cumulative-effect adjustment for adoption of Accounting Standards Update 2016-09						0
Actuarial gain (loss) on defined benefit pension plans, net of tax	(29,000)						(29,000)
Translation adjustments, net of tax	(43,000)						(43,000)
Stockholders' Equity	1,241,667,000	258,000	132,000	471,906,000	(9,158,000)	778,710,000	(181,000)
Stock option exercises		5,000		13,619,000
Stock-based compensation expense		0
Stock-based compensation expense				6,319,000
Payment consideration to tax authority on employees' behalf				0
Cumulative-effect adjustment for adoption of Accounting Standards Update 2016-09				186,000
Tax deficiency from the exercise of stock options				0
Net income	114,141,000					114,141,000
Dividends						(32,709,000)
Cumulative-effect adjustment for adoption of Accounting Standards Update 2014-09						0
Cumulative-effect adjustment for adoption of Accounting Standards Update 2016-09						(115,000)
Actuarial gain (loss) on defined benefit pension plans, net of tax	(84,000)						(84,000)
Translation adjustments, net of tax	(55,000)						(55,000)
Stockholders' Equity	1,342,974,000	263,000	132,000	492,030,000	(9,158,000)	860,027,000	(320,000)
Stock option exercises		4,000		12,591,000
Stock-based compensation expense		1,000
Stock-based compensation expense				5,072,000
Payment consideration to tax authority on employees' behalf				(2,723,000)
Cumulative-effect adjustment for adoption of Accounting Standards Update 2016-09				0
Tax deficiency from the exercise of stock options				0
Net income	82,097,000					82,097,000
Dividends						(39,627,000)
Cumulative-effect adjustment for adoption of Accounting Standards Update 2014-09						587,000
Cumulative-effect adjustment for adoption of Accounting Standards Update 2016-09						0
Actuarial gain (loss) on defined benefit pension plans, net of tax	245,000						245,000
Translation adjustments, net of tax	(27,000)						(27,000)
Stockholders' Equity	$ 1,401,194,000	$ 268,000	$ 132,000	$ 506,970,000	$ (9,158,000)	$ 903,084,000	$ (102,000)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:
Net income	$ 82,097,000	$ 114,141,000	$ 56,391,000
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	52,569,000	33,792,000	30,191,000
Deferred income taxes	11,762,000	(24,815,000)	18,254,000
Stock-based compensation expense	5,073,000	6,319,000	3,323,000
(Gain) loss on sale and retirement of property and equipment	75,000	76,000	(12,000)
Equity in earnings of unconsolidated subsidiaries	(22,000)	(40,000)	(107,000)
Excess tax benefits from the exercise of stock options	0	0	(1,656,000)
Change in assets and liabilities—net of effects from acquired businesses:
Receivables-net	(87,098,000)	18,643,000	(5,611,000)
Prepaid expenses	(613,000)	(3,619,000)	(1,054,000)
Other current assets	17,411,000	(2,622,000)	(10,864,000)
Employee supplemental savings plan asset	1,754,000	(4,172,000)	(1,826,000)
Accounts payable and accrued expenses	5,327,000	(541,000)	(162,000)
Accrued salaries and related expenses	2,095,000	13,095,000	6,926,000
Contract liabilities	6,110,000	1,177,000	(687,000)
Accrued retirement	(3,518,000)	3,936,000	704,000
Other	417,000	(2,412,000)	1,954,000
Net cash flow from operating activities	93,439,000	152,958,000	95,764,000
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Purchases of property and equipment	(30,114,000)	(31,118,000)	(7,662,000)
Acquisition of businesses-net of cash acquired	(5,279,000)	(177,193,000)	(60,556,000)
Deferred contract costs	(5,233,000)	(2,877,000)	0
Investment in capitalized software for internal use	(5,018,000)	(7,744,000)	(2,748,000)
Proceeds from corporate owned life insurance	1,300,000	0	0
Payments to acquire investments	0	(110,000)	(1,183,000)
Proceeds from sale of property and equipment	0	3,000	17,000
Net cash used in investing activities	(44,344,000)	(219,039,000)	(72,132,000)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Borrowings under revolving credit facility	575,500,000	136,500,000	0
Repayments under revolving credit facility	(599,000,000)	(105,500,000)	0
Dividends paid	(39,624,000)	(32,705,000)	(32,139,000)
Proceeds from exercise of stock options	12,595,000	13,624,000	30,562,000
Payment consideration to tax authority on employee's behalf	(2,723,000)	0	0
Debt issuance costs	0	(1,323,000)	(89,000)
Excess tax benefits from the exercise of stock options	0	0	1,656,000
Net cash flow from (used in) financing activities	(53,252,000)	10,596,000	(10,000)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(4,157,000)	(55,485,000)	23,622,000
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	9,451,000	64,936,000	41,314,000
CASH AND CASH EQUIVALENTS, END OF PERIOD	5,294,000	9,451,000	64,936,000
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for interest	2,315,000	1,166,000	983,000
Noncash investing and financing activities:
Capital expenditures incurred but not yet paid	340,000	1,345,000	325,000
Deferred contract costs incurred but not yet paid	$ 0	$ 872,000	$ 0

Description of the Business (No

Description of the Business (Notes)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business [Text Block]	Description of the Business ManTech International Corporation (depending on the circumstances, “ManTech” “Company” “we” “our” “ours” or “us”) provides mission-focused technology solutions and services for U.S. defense, intelligence community and federal civilian agencies. We excel in full-spectrum cyber, data collection & analytics, enterprise IT, systems engineering and software application development solutions that support national and homeland security.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies Principles of Consolidation - Our consolidated financial statements include the accounts of ManTech International Corporation, subsidiaries we control and variable interest entities that are required to be consolidated. All intercompany accounts and transactions have been eliminated. Use of Accounting Estimates - We prepare our consolidated financial statements in conformity with U.S. GAAP, which requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates involve judgments with respect to, among other things, various future economic factors that are difficult to predict and are beyond the control of us. Therefore, actual amounts could differ from these estimates. Revenue Recognition - On January 1, 2018, we adopted Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers using the modified retrospective method applied to those contracts that were not substantially complete as of January 1, 2018. ASC 606 outlines a five-step model whereby revenue is recognized as performance obligations within the contract are satisfied. ASC 606 also requires new, expanded disclosures regarding revenue recognition. We recognized the cumulative effect of adopting ASC 606 as an increase to the 2018 opening balance of retained earnings in the pretax amount of $0.8 million , with the impact primarily related to fixed-price contracts. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts were not adjusted and continue to be reported in accordance with ASC 605, Revenue Recognition . Revenue for the year ended December 31, 2018 increased $2.4 million as a result of applying ASC 606. We account for a contract when: both we and the customer approve and commit; our rights and those of the customer 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, referred to as performance obligations. Then we determine the transaction price for the contract; the consideration to which we can expect in exchange for the promised goods or services in the contract. 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 at 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 distinct performance obligation using our best estimate of the standalone selling price for 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. We recognize revenue over time when there is a continuous transfer of control to our customer. For our U.S. government contracts, this continuous transfer of control to the customer 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. We typically use a cost-based input method to measure progress. Contract costs include labor, material and allocable indirect expenses. Revenue is recognized proportionally as contract costs are incurred plus estimated fees. For time-and-material contracts, we bill the customer per labor hour and per material, and revenue is recognized in the amount invoiced since the amount corresponds directly to the value of our performance to date. For stand-ready service contracts, a time-elapsed output method is used to measure progress, and revenue is recognized straight-line 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 transfer when we have a present right to payment and our customer has legal title. Determining a measure of progress and when control transfers requires us to make judgments that affect the timing of when revenue is recognized. Essentially, all of our contracts satisfy their performance obligations over time. Contracts are often modified to account for changes in contract specifications and requirements. Contract modifications impact performance obligations when the modification either creates new or changes the existing enforceable rights and obligations. The effect of a contract modification on the transaction price and our measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenue and profit cumulatively. Furthermore, a significant change in one or more estimates could affect the profitability of our contracts. We recognize adjustments in estimated profit on contracts in the period identified. The impact of adjustments in contract estimates can be reflected in either revenue or operating expenses on our consolidated statement of income. We have an 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 assumptions and 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 year ended December 31, 2018 , the aggregate impact of adjustments in contract estimates increased our revenue by $9.8 million . No adjustment on any one contract was material to our consolidated financial statements for the year ended December 31, 2018 . Results for prior periods were reported in accordance with ASC 605. Revenue for cost-reimbursable contracts were recorded as reimbursable costs were incurred, including an estimated share of the applicable contractual fees earned. For performance-based fees under cost-reimbursable contracts, we recognized the relevant portion of the expected fee to be awarded by the customer at the time such fee can be reasonably estimated, based on factors such as our prior award experience and communications with the customer regarding performance, or upon approval by the customer. For time-and-materials contracts, revenue was recognized to the extent of billable rates times hours delivered plus materials and other reimbursable costs incurred. For long-term fixed-price contracts, revenue was recognized at a rate per unit as the units were delivered or by other methods to measure services provided. Revenue from other long-term fixed-price contracts were recognized ratably over the contract period or by other appropriate methods to measure services provided. Contract costs were expensed as incurred except for certain limited long-term contracts noted below. For long-term contracts, specifically described in the scope section of ASC 605-35, Revenue Recognition - Construction-Type and Production-Type Contracts , we applied the percentage of completion method. Under the percentage of completion method, income was recognized at a consistent profit margin over the period of performance based on estimated profit margins at completion of the contract. This method of accounting required estimating the total revenue and total contract cost at completion of the contract. These estimates were periodically reviewed and revisions were made as required using the cumulative catch-up method. The impact on revenue and contract profit as a result of these revisions were included in the periods in which the revisions were made. Estimated losses on contracts at completion were recognized when identified. In certain circumstances, revenue was recognized when contract amendments were not finalized. Contract Assets - Amounts are invoiced as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Generally, revenue recognition occurs before billing, resulting in contract assets. These contract assets are referred to as unbilled receivables and are reported within receivables, net on our consolidated balance sheet. Billed Receivables - Amounts billed and due from our customers are classified as billed receivables and are reported within receivables, net on the 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. Contract Liabilities - We receive advances and milestone payments from our customers on selected contracts that exceed revenue earned to date, resulting in contract liabilities. Contract liabilities 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. Contract liabilities are reported on our consolidated balance sheet on a net contract basis at the end of each reporting period. Contract Costs - Contract costs include direct labor, direct materials, overhead and, when applicable, general and administrative expenses. Incremental costs of obtaining a contract that we expect to recover are recognized as deferred contract costs and are amortized on a systematic basis that is consistent with the transfer to the customer of the goods or services. Other incremental costs are expensed when incurred. Costs of fulfilling a contract that relate directly to a contract or to an anticipated contract that can be specifically identified, generate or enhance resources that will be used in satisfying future performance obligations and are expected to be recovered are recognized as deferred contract costs and amortized on a systematic basis that is consistent with the transfer of the goods or services to the customer. Other costs of fulfilling a contract (costs of wasted materials, labor or other resources to fulfill the contracts that were not reflected in the price of the contract and costs that relate to satisfied performance obligations in the contract) are expensed when incurred. Deferred Contract Costs - Costs of obtaining or fulfilling a contract that meet the criteria in ASC 340, Other Assets and Deferred Costs , are capitalized and amortized on a systematic basis that is consistent with the transfer of goods or services to the customer. Deferred contracts costs are reported on our consolidated balance sheet within current or non-current other assets based on the expected life of the related contract. At December 31, 2018 , we had $7.8 million of deferred contract costs related to the fulfillment of future contract obligations. For the year ended December 31, 2018 we recorded amortization expense of $0.5 million . General and Administrative Expenses - General and administrative expenses include the salaries and wages, plus associated fringe benefits of our employees not performing work directly for customers, and associated facilities costs. Among the functions covered by these costs are corporate business development, bid and proposal, contracts administration, finance and accounting, legal, corporate governance and executive and senior management. In addition, we include stock-based compensation, as well as depreciation and amortization expenses related to the general and administrative function. We recognize interest related to unrecognized tax benefits within interest expense and penalties related to unrecognized tax benefits in general and administrative expenses. We classify indirect costs incurred as cost of services and general and administrative expenses in the same manner as such costs are defined in our disclosure statements under U.S. Government Cost Accounting Standards. Cash and Cash Equivalents - For the purpose of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks and short-term investments with maturity dates of three months or less at the date of purchase. Property and Equipment - Property and equipment are recorded at original cost to us. Upon sale or retirement, the costs and related accumulated depreciation or amortization are eliminated from the respective accounts and any resulting gain or loss is included in income. Maintenance and repairs are charged to expense as incurred. Depreciation and Amortization Method - Furniture and office equipment are depreciated using the straight-line method with estimated useful lives ranging from one to seven years . Leasehold improvements are amortized using the straight-line method over the shorter of the asset's useful life or the term of the lease. Goodwill - The purchase price of an acquired business is allocated to the tangible assets, financial assets and separately recognized intangible assets acquired less liabilities assumed based upon their respective fair values, with the excess recorded as goodwill. We review goodwill at least annually for impairment, or whenever events or circumstances indicate that the carrying value of long-lived assets may not be fully recoverable. Other Intangible Assets - Contract rights and other intangible assets are amortized primarily using the pattern of benefits method over periods ranging from one to twenty-five years . We account for the cost of computer software developed or obtained for internal use in accordance with ASC 350-985 , Intangibles - Goodwill and Other - Software . These capitalized software costs are included in other intangible assets, net. We account for software development costs related to software products for sale, lease or otherwise marketed in accordance with ASC 985-20 , Software - Costs of Software to Be Sold, Leased, or Marketed . For projects fully funded by us, development costs are capitalized from the point of demonstrated technological feasibility until the point in time that the product is available for general release to customers. Once the product is available for general release, capitalized costs are amortized based on units sold or on a straight-line basis over a five -year period or other such shorter period as may be required. Impairment of Long-Lived Assets - Whenever events or changes in circumstances indicate that the carrying amount of long-lived assets may not be fully recoverable, we evaluate the probability that future undiscounted net cash flows will be less than the carrying amount of the assets. If any impairment were indicated as a result of this review, we would recognize a loss based on the amount by which the carrying amount exceeds the estimated fair value. Employee Supplemental Savings Plan (ESSP) Assets - We maintain several non-qualified defined contribution supplemental retirement plans for certain key employees that are accounted for in accordance with ASC 710-10-05 , Compensation - General - Deferred Compensation - Rabbi Trust , as the underlying assets are held in rabbi trusts with investments directed by the respective employee. A rabbi trust is a grantor trust generally set up to fund compensation for a select group of management and the assets of this trust are available to satisfy the claims of general creditors in the event of bankruptcy of us. The assets held by the rabbi trusts are recorded at cash surrender value in our consolidated financial statements as ESSP assets with a related liability to employees recorded as a deferred compensation liability in accrued retirement. Stock-based Compensation - We account for stock-based compensation in accordance with ASC 718 , Compensation - Stock Compensation , which requires the use of a valuation model to calculate the fair value of stock-based awards. We have elected to use the Black-Scholes-Merton pricing model to determine fair value of stock options on the dates of grant for our stock options. The fair value is included in operating expenses or capitalized, as appropriate, straight-line over the period in which service is provided in exchange for the award. The grant date fair value of the restricted stock is equal to the closing market price of our common stock on the date of grant. The compensation expense for restricted stock is recognized over the service period and is based on the grant date fair value of the shares. The grant date fair value of the restricted stock unit (RSU) is equal to the closing market price of our common stock on the grant date less the present value of dividends expected to be awarded during the service period. We recognize the grant date fair value of RSUs of shares we expect to issue as compensation expense ratably over the requisite service period. We account for forfeitures as they occur. Income Taxes - We account for income taxes in accordance with ASC 740 , Income Taxes . Under this method, deferred income taxes are determined based on the estimated future tax effects of differences between the financial statement and tax bases of assets and liabilities given the provisions of enacted tax laws. Deferred income tax provisions and benefits are based on changes to the assets or liabilities from year-to-year. In providing for deferred taxes, we consider tax regulations of the jurisdictions in which we operate, estimates of future taxable income and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies vary, adjustments to the carrying value of deferred tax assets and liabilities may be required. Valuation allowances are recorded related to deferred tax assets based on the “more likely than not” criteria. We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain the position following an audit. For tax positions meeting the “more likely than not” threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. Foreign-Currency Translation - All assets and liabilities of foreign subsidiaries are translated into U.S. dollars at fiscal year-end exchange rates. Income and expense items are translated at average monthly exchange rates prevailing during the fiscal year. The resulting translation adjustments are recorded as a component of accumulated other comprehensive income (loss). Comprehensive Income (Loss) - Comprehensive income (loss) consists of net income; translation adjustments, net of tax; and actuarial gain (loss) on defined benefit pension plan, net of tax. Fair Value of Financial Instruments - The carrying value of our cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate their fair value because of the short-term nature of these amounts. Variable Interest Entities (VIEs) - We determine whether we have a controlling financial interest in a VIE. The reporting entity with a variable interest or interest that provides the reporting entity with a controlling financial interest in a VIE will have both (a) the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and (b) the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. We have one entity that has been consolidated as a VIE. The purpose of the entity is to perform on certain U.S. Navy contracts. These contracts ended in 2018. The maximum amount of loss we were exposed to as of December 31, 2018 was not material to our consolidated financial statements. Investments - Investments where we have the ability to exercise significant influence, but we do not control, are accounted for under the equity method of accounting and are included in other assets on our consolidated balance sheets. Significant influence typically exists if we have a 20% to 50% ownership interest in the investee. Under this method of accounting, our share of the net earnings or losses of the investee is included in equity in earnings or losses of unconsolidated subsidiaries on our consolidated statement of income. Investments where we have less than 20% ownership interest in the investee and lack the ability to exercise significant influence are accounted for under the cost method. Under the cost method, we recognize our investment in the stock of an investee as an asset. The investment is measured initially at cost. We recognize as income dividends received that are distributed from net accumulated earnings. Dividends received in excess of earnings are considered a return of investment and are recorded as reductions of costs of the investment. Impairment is assessed at the individual investment level. An investment is impaired if the fair value of the investment is less than its costs. If it is determined that the impairment is other than temporary, then an impairment loss is recognized in earnings. The fair value of the investment would become the new cost basis of the investment and will not be adjusted for subsequent recoveries in fair value. Business Combinations - The accounting for our business combinations consists of allocating the purchase price to tangible and intangible assets acquired and liabilities assumed based on their estimated fair values, with the excess recorded as goodwill. We have up to one year from the acquisition date to use information as of each acquisition date to adjust the fair value of the acquired assets and liabilities, which may result in material changes to their recorded values with an offsetting adjustment to goodwill. Recently Adopted ASUs ASU 2014-09, Revenue from Contracts with Customers (ASC 606) , supersedes existing revenue recognition guidance, including ASC 605-35, Revenue Recognition - Construction-Type and Production-Type Contracts . ASU 2014-09 outlines a single set of comprehensive principles for recognizing revenue under GAAP. Among other things, it requires companies to identify contractual performance obligations and determine whether revenue should be recognized at a point in time or over time. It also requires new, expanded disclosures regarding revenue recognition. We elected to adopt using the modified retrospective method that applied to those contracts that were not substantially completed as of January 1, 2018. Additional details are included in the revenue recognition policy above and Note 3 below. ASU 2017-09, Compensation—Stock Compensation (ASC 718): Scope of Modification Accounting , provides guidance concerning which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in ASC 718. Specifically, an entity is to account for the effects of a modification, unless all of the following are satisfied: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and (3) the classification of the modified award as an equity instrument or as a liability instrument is the same as the classification of the original award immediately before the original award is modified. The current disclosure requirements in ASC 718 apply regardless of whether an entity is required to apply modification accounting under the amendments in ASU 2017-09. The adoption of this ASU on January 1, 2018 did not have an effect on our consolidated financial statements. ASU 2017-01, Business Combinations (ASC 805)—Clarifying the Definition of a Business , clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. Under the guidance in Topic 805, there are three elements of a business: inputs, processes and outputs. While an integrated set of assets and activities (collectively, a “set”) that is a business usually has outputs, outputs are not required to be present. Additionally, all of the inputs and processes that a seller uses in operating a set are not required if market participants can acquire the set and continue to produce outputs. The amendments in ASU 2017-01 provide a screen to determine when a set is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This screen reduces the number of transactions that need to be further evaluated. If, however, the screen is not met, then the amendments in this ASU (1) require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs and (2) remove the evaluation of whether a market participant could replace missing elements. Finally, the amendments in this ASU narrow the definition of the term “output” so that the term is consistent with the manner in which outputs are described in ASC 606. The adoption of this ASU on January 1, 2018 did not have an effect on our consolidated financial statements. ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . This ASU addresses the following eight specific cash flow issues: Debt prepayment or debt extinguishment costs; settlement of zero coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies (including bank-owned life insurance policies); distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. We applied the equity method of accounting for applicable investments. We made an accounting policy election to classify distributions received from equity method investees using the cumulative earnings approach. Distributions received are considered returns on investment and classified as cash inflows from operating activities, unless the investor’s cumulative distributions received less distributions received in prior periods that were determined to be returns of investment exceed cumulative equity in earnings recognized by the investor (as adjusted for amortization of basis differences). When such an excess occurs, the current-period distribution up to this excess is considered a return of investment and should be classified as cash inflows from investing. Due to the adoption of ASU 2016-15 on January 1, 2018, we classified proceeds from settlements of corporate-owned life insurance policies as investing activities on our consolidated statement of cash flows for the year ended December 31, 2018 . Recently Issued But Not Yet Adopted ASUs The FASB has issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 , which resolves the diversity in practice concerning the manner in which entities account for transactions on the basis of their view of the economics of the collaborative arrangement. A collaborative arrangement, as defined by the guidance in Topic 808, is a contractual arrangement under which two or more parties actively participate in a joint operating activity and are exposed to significant risks and rewards that depend on the activity’s commercial success. In particular, the amendments in ASU 2018-18 (1) clarify that certain transactions between collaborative participants should be accounted for as revenue under Topic 606 when the collaborative participant is a customer in the context of the unit of account, and that, in those situations, all the guidance in Topic 606 should be applied, including recognition, measurement, presentation, and disclosure requirements; (2) add unit-of-account guidance in Topic 808 to align with the guidance in Topic 606 (i.e., a distinct good or service), limited to when an entity is assessing whether the collaborative arrangement or a part of the arrangement is within the scope of Topic 606; and (3) clarify that in a transaction that is not directly related to sales to third parties, presenting the transaction as revenue would be precluded if the collaborative participant counterparty was not a customer. The amendments are effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. Note that early adoption is permitted, including adoption in any interim period for public business entities for periods for which financial statements have not yet been issued. We are currently evaluating the effect on our consolidated financial statements. The FASB issued ASU 2016-02, Leases (Topic 842) . The amendments in this ASU create Topic 842, Leases , and supersede the leases requirements in Topic 840, Leases . The objective of Topic 842 is to establish the principles that lessees and lessors should apply to report useful information to users of financial statements about the amount, timing and uncertainty of cash flows arising from a lease. This ASU is effective for public entities for annual periods after December 15, 2018, and interim periods therein. Early adoption is permitted for all entities. We developed and substantially completed a detailed implementation plan which includes; implementing a software platform for lease accounting; updating our policies and controls; and developing disclosures. We will adopt ASU 2016-02 retrospectively at the b

Revenue from Contract with Cust

Revenue from Contract with Customers (Notes)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue from Contracts with Customers We derive revenue from contracts with customers primarily from contracts with the U.S. government in the areas of defense, intelligence, homeland security and other federal civilian agencies. Substantially all of our revenue is derived from services and solutions provided to the U.S. government or to prime contractors supporting the U.S. government, including services by our employees and our subcontractors, and solutions that include third-party hardware and software that we purchase and integrate as a part of our overall solutions. Customer requirements may vary from period-to-period depending on specific contract and customer requirements. We provide our services and solutions under three types of contracts: cost-reimbursable, fixed-price and time-and-materials. Under cost-reimbursable contracts, we are reimbursed for costs that are determined to be reasonable, allowable and allocable to the contract and paid a fee representing the profit margin negotiated between us and the contracting agency, which may be fixed or performance based. Under fixed-price contracts, we perform specific tasks for a fixed price. Fixed-price contracts may include either a product delivery or specific service performance over a defined period. Under time-and-materials contracts, we are reimbursed for labor at fixed hourly rates and generally reimbursed separately for allowable materials, costs and expenses at cost. We have one reportable segment. Our U.S. government customers typically exercise independent decision-making and contracting authority. Offices or divisions within an agency or department of the U.S. government may directly, or through a prime contractor, use our services as a separate customer as long as the customer has independent decision-making and contracting authority within its organization. We treat sales to U.S. government customers as sales within the U.S. regardless of where the services are performed. The following tables disclose revenue (in thousands) by contract type, customer, prime or subcontractor and geography for the periods presented. Prior period amounts have not been adjusted under the modified retrospective method. Year Ended December 31, 2018 2017 2016 Cost-reimbursable $ 1,325,024 $ 1,130,134 $ 1,085,429 Fixed-price 435,599 370,517 306,735 Time-and-materials 197,934 216,367 209,432 $ 1,958,557 $ 1,717,018 $ 1,601,596 Year Ended December 31, 2018 2017 2016 Department of Defense and intelligence agencies $ 1,436,627 $ 1,359,309 $ 1,331,551 Federal civilian agencies 476,834 315,036 230,399 State agencies, international agencies and commercial entities 45,096 42,673 39,646 $ 1,958,557 $ 1,717,018 $ 1,601,596 Year Ended December 31, 2018 2017 2016 Prime contractor $ 1,742,097 $ 1,514,924 $ 1,404,490 Subcontractor 216,460 202,094 197,106 $ 1,958,557 $ 1,717,018 $ 1,601,596 Year Ended December 31, 2018 2017 2016 U.S $ 1,928,785 $ 1,688,671 $ 1,576,290 International 29,772 28,347 25,306 $ 1,958,557 $ 1,717,018 $ 1,601,596 We deliver a broad array of IT and technical services solutions under contracts with the U.S. government, state and local governments and commercial customers. The components of contract receivables are as follows (in thousands): December 31, 2018 January 1, 2018 December 31, 2017 Billed receivables $ 301,716 $ 236,113 $ 236,113 Unbilled receivables 109,895 88,767 81,454 Allowance for doubtful accounts (6,233 ) (6,157 ) (6,157 ) Receivables-net $ 405,378 $ 318,723 $ 311,410 Receivables at December 31, 2018 are expected to be substantially collected within one year except for approximately $0.8 million , of which 94% is related to receivables from sales to the U.S. government or from contracts in which we acted as a subcontractor to other contractors selling to the U.S. government. We have one contract which accounts for 12% of our accounts receivable balance. We do not believe that we have significant exposure to credit risk as billed receivable and unbilled receivables are primarily due from the U.S. government. The allowance for doubtful accounts represents our estimate for exposure to compliance, contractual issues and bad debts related to prime contractors. The following table discloses contract liabilities (in thousands): December 31, 2018 January 1, 2018 December 31, 2017 Contract liabilities $ 28,209 $ 22,156 $ 18,816 Changes in the balance of contract liabilities are primarily due to the timing difference between our performance and our customers' payments. For the year ended December 31, 2018 , the amount of revenue that was included in the opening contract liabilities balance was $18.2 million . The remaining performance obligation at December 31, 2018 was $2.8 billion . The following table discloses when we expect to recognize the remaining performance obligation as revenue (in billions): For the year ending December 31, 2019 December 31, 2020 Thereafter Total Revenue expected to be recognized $ 1.6 $ 0.8 $ 0.4 $ 2.8

Acquisitions (Notes)

Acquisitions (Notes)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Acquisitions [Text Block]	Acquisitions InfoZen LLC (InfoZen) —On October 2, 2017 , we completed the acquisition of InfoZen. The results of InfoZen's operations have been included in our consolidated financial statements since that date. The acquisition was completed through an equity purchase agreement dated September 15, 2017 , by and among InfoZen LLC., IZ Holdings, LLC and other beneficiaries and ManTech Advanced Systems International, Inc. We funded the acquisition with cash on hand and borrowings on our revolving credit facility. InfoZen is a leading IT solution provider, with domain expertise in modernization, agile/DevOps software development, cloud migration and threat monitoring and assessment capabilities in support of critical national and homeland security missions. The purchase agreement did not contain provisions for contingent consideration. For the year ended December 31, 2017, we incurred approximately $0.8 million of acquisition costs related to the InfoZen transaction, which are included in general and administrative expenses in our consolidated statement of income. The purchase price of $184.0 million was allocated to the underlying assets and liabilities based on their estimated fair value at the date of acquisition. The goodwill recorded related to this transaction will be deductible for tax purposes over 15 years . Recognition of goodwill is largely attributed to the value paid for InfoZen's capabilities to support customers in modernization, agile software development, cloud migration and threat monitoring assessment capabilities. In allocating the purchase price, we considered, among other factors, analysis of historical financial performance and estimates of future performance of InfoZen's contracts. The components of other intangible assets associated with the acquisition were customer relationships and backlog valued at $49.2 million and $5.7 million , respectively. Customer contracts and related relationships represent the underlying relationships and agreements with InfoZen's existing customers. Customer relationships are amortized using the pattern of benefits method over their estimated useful lives of approximately 20 years . Backlog is amortized straight-line over its estimated useful life of 1 year . The weighted-average amortization period for the intangible assets is 18 years . The following table represents the purchase price allocation for InfoZen (in thousands): Cash and cash equivalents $ 1,406 Receivables 8,991 Prepaid expenses 4,046 Other current assets 7 Goodwill 129,932 Other intangible assets 54,850 Property and equipment 485 Other assets 111 Accounts payable and accrued expenses (7,488 ) Accrued salaries and related expenses (3,092 ) Contract liabilities (5,258 ) Net assets acquired and liabilities assumed $ 183,990

Earnings per Share (Notes)

Earnings per Share (Notes)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Earnings per Share Under ASC 260 , Earnings per Share , the two-class method is an earnings allocation formula that determines earnings per share for each class of common stock according to dividends declared (or accumulated) and participation rights in undistributed earnings. Under that method, basic and diluted earnings per share data are presented for each class of common stock. In applying the two-class method, we determined that undistributed earnings should be allocated equally on a per share basis between Class A and Class B common stock. Under our Certificate of Incorporation, the holders of the common stock are entitled to participate ratably, on a share-for-share basis as if all shares of common stock were of a single class, in such dividends, as may be declared by the Board of Directors. During the years ended December 31, 2018 , 2017 and 2016 , we declared and paid quarterly dividends, in the amount of $0.25 , $0.21 and $0.21 per share on both classes of common stock. Basic earnings per share has been computed by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding during each period. Shares issued during the period and shares reacquired during the period are weighted for the portion of the period in which the shares were outstanding. Diluted earnings per share have been computed in a manner consistent with that of basic earnings per share while giving effect to all potentially dilutive common shares that were outstanding during each period. The net income available to common stockholders and weighted average number of common shares outstanding used to compute basic and diluted earnings per share for each class of common stock are as follows (in thousands, except per share amounts): Year Ended 2018 2017 2016 Distributed earnings $ 39,627 $ 32,709 $ 32,138 Undistributed earnings 42,470 81,432 24,253 Net income $ 82,097 $ 114,141 $ 56,391 Class A common stock: Basic net income available to common stockholders $ 54,715 $ 75,413 $ 36,885 Basic weighted average common shares outstanding 26,354 25,685 24,944 Basic earnings per share $ 2.08 $ 2.94 $ 1.48 Diluted net income available to common stockholders $ 54,937 $ 75,698 $ 36,988 Effect of potential exercise of stock options 324 288 202 Diluted weighted average common shares outstanding 26,678 25,973 25,146 Diluted earnings per share $ 2.06 $ 2.91 $ 1.47 Class B common stock: Basic net income available to common stockholders $ 27,382 $ 38,728 $ 19,506 Basic weighted average common shares outstanding 13,189 13,190 13,192 Basic earnings per share $ 2.08 $ 2.94 $ 1.48 Diluted net income available to common stockholders $ 27,160 $ 38,443 $ 19,403 Diluted weighted average common shares outstanding 13,189 13,190 13,192 Diluted earnings per share $ 2.06 $ 2.91 $ 1.47 For the years ended December 31, 2018 , 2017 and 2016 , options to purchase 293,898 shares, 265,866 shares and 369,300 shares, respectively, were outstanding but not included in the computation of diluted earnings per share because the options' effect would have been anti-dilutive. For the years ended December 31, 2018 , 2017 and 2016 , there were 420,524 shares, 463,800 shares and 1,045,789 shares, respectively, issued from the exercise of stock options.

Property and Equipment (Notes)

Property and Equipment (Notes)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment [Text Block]	Property and Equipment Major classes of property and equipment are summarized as follows (in thousands): December 31, 2018 2017 Furniture and equipment $ 97,577 $ 79,218 Leasehold improvements 43,065 39,022 Property and equipment-gross 140,642 118,240 Accumulated depreciation and amortization (89,215 ) (72,158 ) Property and equipment-net $ 51,427 $ 46,082 Depreciation and amortization expense related to property and equipment for the years ended December 31, 2018 , 2017 and 2016 was $25.5 million , $9.5 million and $7.8 million , respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets (Notes)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets [Text Block]	Goodwill and Other Intangible Assets Under ASC 350 , Intangibles - Goodwill and Other , goodwill is to be reviewed at least annually for impairment and whenever events or circumstances indicate that the carrying value of goodwill may not be fully recoverable. We have elected to perform this annual review as of October 31st of each calendar year. In reviewing goodwill for impairment, we have the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If we elect to perform a qualitative assessment and determine that an impairment is more likely than not, the entity is then required to perform the existing two-step quantitative impairment test (described below), otherwise no further analysis is required. We also may elect not to perform the qualitative assessment and, instead, proceed directly to the two-step quantitative impairment test. The goodwill impairment test is a two-step process performed at the reporting unit level. The first step of the goodwill impairment test compares the fair value of a reporting unit with its carrying amount (including goodwill). If the reporting unit's fair value exceeds its carrying value, no further procedures are required. However, if the reporting unit's fair value is less than its carrying value, an impairment of goodwill may exist, requiring a second step to be performed. Step two of this test measures the amount of the impairment loss, if any. Step two of this test requires the allocation of the reporting unit's fair value to its assets and liabilities, including any unrecognized intangible assets in a hypothetical analysis that calculates the implied fair value of goodwill as if the reporting unit were being acquired in a business combination. If the implied fair value of goodwill is less than the carrying value, the difference is recorded as a goodwill impairment charge in operations. The fair values of the reporting units are determined based on a weighting of the income approach, market approach and market transaction approach. The income approach is a valuation technique in which fair value is based from forecasted future cash flow discounted at the appropriate rate of return commensurate with the risk as well as current rates of return for equity and debt capital as of the valuation date. The forecast used in our estimation of fair value was developed by management based on a contract basis, incorporating adjustments to reflect known contract and market considerations (such as reductions and uncertainty in government spending, pricing pressure and opportunities). The discount rate utilizes a risk adjusted weighted average cost of capital. The market approach is a valuation technique in which the fair value is calculated based on market prices realized in an actual arm's length transaction. The technique consists of undertaking a detailed market analysis of publicly traded companies that provides a reasonable basis for comparison to us. Valuation ratios, which relate market prices to selected financial statistics derived from comparable companies, are selected and applied to us after consideration of adjustments for financial position, growth, market, profitability and other factors. The market transaction approach is a valuation technique in which the fair value is calculated based on market prices realized in actual arm's length transactions. The technique consists of undertaking a detailed market analysis of merged and acquired companies that provides a reasonable basis for comparison to us. Valuation ratios, which relate market prices to selected financial statistics derived from comparable companies, are selected and applied to us after consideration of adjustments for financial position, growth, market, profitability and other factors. To assess the reasonableness of the calculated reporting unit fair values, we compare the sum of the reporting units' fair values to our market capitalization (per share stock price times the number of shares outstanding) and calculate an implied control premium (the excess of the sum of the reporting units' fair values over the market capitalization) and then assess the reasonableness of our implied control premium. The changes in the carrying amounts of goodwill during fiscal years 2018 and 2017 were as follows (in thousands): Goodwill Balance Goodwill at December 31, 2016 $ 955,874 Acquisitions 128,686 Goodwill at December 31, 2017 1,084,560 Acquisition fair value adjustment 1,246 Goodwill at December 31, 2018 $ 1,085,806 Other intangible assets consisted of the following (in thousands): December 31, 2018 December 31, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Other intangible assets: Contract and program intangible assets $ 355,932 $ 201,298 $ 154,634 $ 355,932 $ 179,049 $ 176,883 Capitalized software cost for internal use 50,925 33,597 17,328 46,995 29,530 17,465 Total other intangible assets-net $ 406,857 $ 234,895 $ 171,962 $ 402,927 $ 208,579 $ 194,348 Amortization expense relating to intangible assets for the years ended December 31, 2018 , 2017 and 2016 was $26.3 million , $23.5 million and $21.8 million , respectively. We estimate that we will have the following amortization expense for the future periods indicated below (in thousands): Year ending: December 31, 2019 $ 22,621 December 31, 2020 $ 21,781 December 31, 2021 $ 19,051 December 31, 2022 $ 16,456 December 31, 2023 $ 13,485

Debt (Notes)

Debt (Notes)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt [Text Block]	Debt Revolving Credit Facility - We maintain a credit agreement with a syndicate of lenders led by Bank of America, N.A., as sole administrative agent. The credit agreement provides for a $500 million revolving credit facility, with a $75 million letter of credit sublimit and a $30 million swing line loan sublimit. The credit agreement also includes an accordion feature that permits us to arrange with the lenders for the provision of additional commitments. The maturity date is August 17, 2022 . Borrowings under our credit agreement are collateralized by substantially all of our assets and our Material Subsidiaries (as defined in the credit agreement) and bear interest at one of the following variable rates as selected by us at the time of borrowing: a LIBOR based rate plus market spreads ( 1.25% to 2.25% based on our consolidated total leverage ratio) or Bank of America's base rate plus market spreads ( 0.25% to 1.25% based on our consolidated total leverage ratio). The aggregate annual weighted average interest rates were 3.91% and 2.99% for the years ended December 31, 2018 and 2017 , respectively. The terms of the credit agreement permit prepayment and termination of the loan commitments at any time, subject to certain conditions. The credit agreement requires us to comply with specified financial covenants, including the maintenance of certain leverage ratios and a certain consolidated coverage ratio. The credit agreement also contains various covenants, including affirmative covenants with respect to certain reporting requirements and maintaining certain business activities, and negative covenants that, among other things, may limit or impose restrictions on our ability to incur liens, incur additional indebtedness, make investments, make acquisitions and undertake certain other actions. As of, and during the fiscal years ending, December 31, 2018 and 2017 , we were in compliance with our financial covenants under the credit agreement. There was $7.5 million and $31.0 million outstanding on our revolving credit facility at December 31, 2018 and 2017 , respectively. The weighted average borrowings under the revolving portion of the facility during the years ended December 31, 2018 and 2017 were $34.2 million and $2.7 million , respectively. The maximum available borrowing under the revolving credit facility at December 31, 2018 was $482.9 million . At December 31, 2018 and 2017 , we have $9.6 million and $15.3 million , respectively, outstanding on our letter of credit that reduces our availability to borrow under our revolving credit facility.

Commitments and Contingencies (

Commitments and Contingencies (Notes)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies Contracts with the U.S. government, including subcontracts, are subject to extensive legal and regulatory requirements and, from time-to-time, agencies of the U.S. government, in the ordinary course of business, investigate whether our operations are conducted in accordance with these requirements and the terms of the relevant contracts. U.S. government investigations of us, whether related to our U.S. government contracts or conducted for other reasons, could result in administrative, civil, or criminal liabilities, including repayments, fines or penalties being imposed upon us, or could lead to suspension or debarment from future U.S. government contracting activities. Management believes it has adequately reserved for any losses that may be experienced from any investigation of which it is aware. The Defense Contract Audit Agency has completed our incurred cost audits through 2015 with adjustments expected to be settled within established reserves. The remaining audits for 2016 through 2018 are not expected to have a material effect on our financial position, results of operations or cash flow and management believes it has adequately reserved for any losses. In the normal course of business, we are involved in certain governmental and legal proceedings, claims and disputes and have litigation pending under several suits. We believe that the ultimate resolution of these matters will not have a material effect on our financial position, results of operations or cash flows, except for the matter noted below. An officer of our Company is a party to a pending arbitration proceeding with a former employer that relates to certain breach of contract claims. Pursuant to indemnification arrangements we have with this officer, we may be exposed to a potential loss related to this claim. Pursuant to applicable accounting standards, we have determined that it is not probable that an unfavorable outcome could cause us to incur a liability/loss under these indemnification arrangements. However, given the nature of the claim, the early stage of the process, the limitations on information and other factual details relating to the claims that are available to us at this time and management’s intent to contest the matter vigorously, we are unable to make a reasonable estimate of loss at this time. As such, we have not accrued, nor disclosed an amount of potential loss as of December 31, 2018 . We were a defendant in a lawsuit filed by two former employees with allegations of retaliation under both the False Claims Act and the Defense Contractor Whistleblower Protection Act. A jury found ManTech liable for discharging the two former employees. Both parties filed appeals to the Fourth Circuit Court of Appeals. In August 2018, the Fourth Circuit Court of Appeals reversed the finding of liability as to one of the former employees and affirmed the finding of liability as to the other former employee in the amount of $1.4 million . Our insurance policy covers the amount of the liability, therefore, no loss was recognized for the year ended December 31, 2018 . The impact of future events in connection with this matter is not expected to have a material effect on our financial position, results of operations or cash flow. We have $9.6 million outstanding on our letter of credit, of which $9.5 million is related to an outstanding performance bond in connection with a contract between ManTech MENA, LLC and Jadwalean International Operations and Management Company to fulfill technical support requirements for the Royal Saudi Air Force. We lease office space and equipment under long-term operating leases. A number of the leases contain renewal options and escalation clauses. Office space and equipment rent expense totaled approximately $39.9 million , $36.9 million and $37.4 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. We had $13.2 million and $10.6 million of deferred rent liabilities resulting from recording rent expense on a straight-line basis over the life of the respective lease for the years ended December 31, 2018 and 2017 , respectively. At December 31, 2018 , our aggregate future minimum rental commitments under these leases are as follows (in thousands): Total Year ending: December 31, 2019 $ 33,953 December 31, 2020 28,954 December 31, 2021 25,794 December 31, 2022 21,852 December 31, 2023 18,353 Thereafter 9,296 Total $ 138,202

Stockholders Equity and Stock-B

Stockholders Equity and Stock-Based Compensation (Notes)	12 Months Ended
	Dec. 31, 2018
Stockholders Equity and Stock-Based Compensation [Abstract]
Stockholders Equity and Stock-Based Compensation [Text Block]	Stockholders' Equity and Stock-Based Compensation Common Stock - We have 150,000,000 shares of authorized Class A common stock, par value $0.01 per share. We have 50,000,000 shares of authorized Class B common stock, par value $0.01 per share. On December 31, 2018 , there were 26,573,400 shares of Class A common stock outstanding, 244,113 shares of Class A common stock recorded as treasury stock and 13,188,045 shares of Class B common stock outstanding. Holders of Class A common stock are entitled to one vote for each share held of record and holders of Class B common stock are entitled to ten votes for each share held of record, except with respect to any “going private transaction” (generally, a transaction in which George J. Pedersen (our Executive Chairman and Chairman of the Board), his affiliates, his direct and indirect permitted transferees or a group, generally including Mr. Pedersen, such affiliates and permitted transferees, seek to buy all outstanding shares), as to which each share of Class A common stock and Class B common stock are entitled to one vote per share. The Class A common stock and the Class B common stock vote together as a single class on all matters submitted to a vote of stockholders, including the election of directors, except as required by law. Holders of common stock do not have cumulative voting rights in the election of directors. Stockholders are entitled to receive, when and if declared by the Board of Directors from time-to-time, such dividends and other distributions in cash, stock or property from our assets or funds legally and contractually available for such purposes subject to any dividend preferences that may be attributable to preferred stock that may be authorized. Each share of Class A common stock and Class B common stock is equal in respect to dividends and other distributions in cash, stock or property, except that in the case of stock dividends, only shares of Class A common stock will be distributed with respect to the Class A common stock and only shares of Class B common stock will be distributed with respect to Class B common stock. In no event will either Class A common stock or Class B common stock be split, divided or combined unless the other class is proportionately split, divided or combined. The shares of Class A common stock are not convertible into any other series or class of securities. Each share of Class B common stock, however, is freely convertible into one share of Class A common stock at the option of the Class B stockholder. Upon the death of Mr. Pedersen, all outstanding shares of Class B common stock automatically convert to Class A common stock. Preferred Stock - We are authorized to issue an aggregate of 20,000,000 shares of preferred stock, $0.01 par value per share, the terms and conditions of which are determined by our Board of Directors upon issuance. The rights, preferences and privileges of holders of our common stock are subject to, and may be adversely affected by, the rights of holders of any shares of preferred stock that we may designate and issue in the future. At December 31, 2018 and 2017 , no shares of preferred stock were outstanding and the Board of Directors currently has no plans to issue a series of preferred stock. Accounting for Stock-Based Compensation: Our 2016 Management Incentive Plan (the Plan) was designed to attract, retain and motivate key employees. The types of awards available under the Plan include stock options, restricted stock and RSUs. Equity awards granted under the Plan are settled in shares of Class A common stock. At the beginning of each year, the Plan provides that the number of shares available for issuance automatically increases by an amount equal to 1.5% of the total number of shares of Class A and Class B common stock outstanding on December 31st of the previous year. On January 2, 2019 , there were 596,422 additional shares made available for issuance under the Plan. Through December 31, 2018 , the Board of Directors has authorized the issuance of up to 14,551,899 shares under this Plan. Through December 31, 2018 , the remaining aggregate number of shares of our common stock available for future grants under the Plan was 6,113,209 . The Plan expires in March 2026 . The Plan is administered by the compensation committee of our Board of Directors, along with its delegates. Subject to the express provisions of the Plan, the committee has the Board of Directors' authority to administer and interpret the Plan, including the discretion to determine the exercise price, vesting schedule, contractual life and the number of shares to be issued. Stock Compensation Expense - For the years ended December 31, 2018 , 2017 and 2016 , we recorded $5.1 million , $6.3 million and $3.3 million of stock-based compensation expense, respectively. No compensation expense of employees with stock awards was capitalized during the years ended December 31, 2018 , 2017 and 2016 . For the year ended December 31, 2018 and 2017 , we recorded $3.1 million and $2.7 million to income tax expense for tax benefits related to the exercise of stock options, vested cancellations and the vesting of restricted stock. For the year ended December 31, 2016 , we recorded $0.1 million to paid in capital related to tax deficiencies from the exercise of stock options, vested cancellations and the vesting of restricted stock. Stock Options - Under the Plan, we have issued stock options. A stock option granted gives the holder the right, but not the obligation to purchase a certain number of shares at a predetermined price for a specific period of time. We typically issue options that vest over three years in equal installments beginning on the first anniversary of the date of grant. Under the terms of the Plan, the contractual life of the option grants may not exceed eight years . During the years ended December 31, 2018 , 2017 and 2016 , we issued options that expire five years from the date of grant. Fair Value Determination - We have used the Black-Scholes-Merton option pricing model to determine fair value of our stock option awards on the date of grant. We will reconsider the use of the Black-Scholes-Merton model if additional information becomes available in the future that indicates another model would be more appropriate or if grants issued in future periods have characteristics that cannot be reasonably estimated under this model. The following weighted-average assumptions were used for option grants during the years ended December 31, 2018 , 2017 and 2016 : • Volatility - The expected volatility of the options granted was estimated based upon historical volatility of our share price through weekly observations of our trading history. • Expected life of options - The expected life of options granted to employees was determined from historical exercises of the grantee population. The options had graded vesting over three years in equal installments beginning on the first anniversary of the date of the grant and a contractual term of five years . • Risk-free interest rate - The yield on zero-coupon U.S. Treasury strips was used to extrapolate a forward-yield curve. This “term structure” of future interest rates was then input into a numeric model to provide the equivalent risk-free rate to be used in the Black-Scholes-Merton model based on the expected term of the underlying grants. • Dividend yield - The Black-Scholes-Merton valuation model requires an expected dividend yield as an input. For the years ended December 31, 2018 , 2017 and 2016 , we have calculated our expected dividend yield based on an expected annual cash dividend of $1.00 per share, $0.84 per share and $0.84 per share, respectively. The following table summarizes weighted-average assumptions used in our calculations of fair value for the years ended December 31, 2018 , 2017 and 2016 : Year Ended 2018 2017 2016 Volatility 26.57 % 25.59 % 23.70 % Expected life of options 3 years 3 years 3 years Risk-free interest rate 2.72 % 1.72 % 1.10 % Dividend yield 2.00 % 2.75 % 2.88 % Stock Option Activity - The weighted-average fair value of options granted during the years ended December 31, 2018 , 2017 and 2016 , as determined under the Black-Scholes-Merton valuation model, was $10.42 , $6.75 and $4.60 , respectively. Option grants that vested during the years ended December 31, 2018 , 2017 and 2016 had a combined fair value of $1.5 million , $1.7 million and $2.6 million , respectively. The following table summarizes stock option activity for the years ended December 31, 2018 , 2017 and 2016 : Number of Shares Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Life Stock options outstanding at December 31, 2015 2,495,310 $ 30.86 $ 3,583 Granted 199,938 $ 34.22 Exercised (1,045,789 ) $ 29.24 $ 8,858 Cancelled and expired (489,040 ) $ 37.91 Stock options outstanding at December 31, 2016 1,160,419 $ 29.93 $ 14,299 Granted 534,030 $ 42.90 Exercised (463,800 ) $ 29.34 $ 7,203 Cancelled and expired (61,241 ) $ 33.80 Stock options outstanding at December 31, 2017 1,169,408 $ 35.88 $ 16,731 Granted 466,828 $ 54.87 Exercised (420,524 ) $ 30.05 $ 12,411 Cancelled and expired (122,312 ) $ 43.85 Stock options outstanding at December 31, 2018 1,093,400 $ 45.34 $ 8,776 4 years Stock options exercisable at December 31, 2018 318,998 $ 35.57 $ 5,336 2 years The following table summarizes non-vested stock options for the year ended December 31, 2018 : Number of Shares Weighted Average Fair Value Non-vested stock options at December 31, 2017 684,979 $ 6.23 Granted 466,828 $ 10.42 Vested (257,293 ) $ 5.83 Cancelled (120,112 ) $ 7.04 Non-vested stock options at December 31, 2018 774,402 $ 8.77 Unrecognized compensation expense related to outstanding stock options was $5.6 million as of December 31, 2018 , which is expected to be recognized over a weighted-average period of 2 years and will be adjusted for forfeitures as they occur. Restricted Stock - Under the Plan, we have issued restricted stock. A restricted stock award is an issuance of shares that cannot be sold or transferred by the recipient until the vesting period lapses. Restricted stock issued to members of our Board of Directors vest in one year . The related compensation expense is recognized over the service period and is based on the grant date fair value of the stock and the number of shares expected to vest. The grant date fair value of the restricted stock is equal to the closing market price of our common stock on the date of grant. Restricted Stock Activity - The following table summarizes the restricted stock activity during the years ended December 31, 2018 and 2017 : Number of Shares Weighted Average Fair Value Non-vested restricted stock at December 31, 2016 18,000 $ 33.84 Granted 24,000 $ 37.90 Vested (18,000 ) $ 33.84 Non-vested restricted stock at December 31, 2017 24,000 $ 37.90 Granted 24,000 $ 52.83 Vested (28,000 ) $ 40.03 Non-vested restricted stock at December 31, 2018 20,000 $ 52.83 RSUs - Under the Plan, we issued performance-based and time-based RSUs. RSUs are not actual shares, but rather a right to receive shares in the future. The shares are not issued and the employee cannot sell or transfer shares prior to vesting and has no voting rights until the RSUs vest. Employees who are granted RSUs do not receive dividend payments during the vesting period. The employees' performance-based RSUs will result in the delivery of shares if (a) performance criteria is met and (b) the employee remains employed, in good standing, through the date of the performance period of 2 years . The employees' time-based RSUs will result in the delivery of shares in one-third increments on the first, second and third anniversaries of the date of grant. The grant date fair value of the RSUs is equal to the closing market price of our common stock on the grant date less the present value of dividends expected to be awarded during the service period. We recognize the grant date fair value of RSUs of shares we expect to issue as compensation expense ratably over the requisite service period. RSU Activity - For performance-based RSUs that vested in 2018, each RSU awarded resulted in the issuance of 1.5 shares, which were issued net of applicable payroll tax withholdings. The following table summarizes the RSU activity during the years ended December 31, 2018 and 2017 : Number of Units Weighted Average Fair Value RSUs at December 31, 2016 206,338 $ 30.10 Granted 55,830 $ 35.34 Vested (3,300 ) $ 30.60 Forfeited (97,525 ) $ 31.00 RSUs at December 31, 2017 161,343 $ 31.36 Granted 76,713 $ 53.97 Vested (87,200 ) $ 28.40 Forfeited (13,260 ) $ 38.98 RSUs at December 31, 2018 137,596 $ 45.11

Retirement Plans (Notes)

Retirement Plans (Notes)	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Retirement Plans [Text Block]	Retirement Plans As of December 31, 2018 , we maintained a qualified defined contribution plan. Our qualified defined contribution plan covers substantially all employees and complies with Section 401 of the Internal Revenue Code. Under this plan, we stipulated a basic matching contribution that matches a portion of the participants' contribution based upon a defined schedule. Additionally, this plan contains a discretionary contribution component where we may contribute additional amounts based on a percentage of eligible employees' compensation. Contributions are invested by an independent investment company. The choice of investment alternatives is at the election of each participating employee. Our contributions to the plan were approximately $23.5 million , $20.6 million and $19.8 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. As of December 31, 2018 , we also maintained an Employee Supplemental Savings Plan (ESSP), which is a nonqualified deferred compensation plan for certain key employees. Under this plan, eligible employees may defer up to 75% of qualified annual base compensation and 100% of bonus. In the ESSP, participant deferral accounts are credited with a rate of return based on investment elections as selected by the participant. The assets related to the ESSP are held in a rabbi trust owned by us for benefit of the participating employees. The trust investments are in the form of variable universal life insurance products, which are owned by us. These investments seek to replicate the return of the participant investment elections. Employee contributions to this plan were approximately $3.4 million , $3.0 million and $2.6 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. We maintained a nonqualified supplemental defined benefit pension plan for certain retired employees of an acquired company as of December 31, 2018 . These plans were informally and partially funded beginning in 1999 through a rabbi trust. Assets held in a rabbi trust are not eligible to be included in the calculation of plan status. At both December 31, 2018 and 2017 , 100% of the rabbi trust assets were invested in a money market account with a commercial bank. All covered employees retired prior to 1998. Our benefit obligation was $0.8 million and $1.2 million at December 31, 2018 and 2017 , respectively.

Income Taxes (Notes)

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes [Text Block]	Income Taxes The domestic and foreign components of income operations before income taxes and equity method investments were as follows (in thousands): Year Ended 2018 2017 2016 Domestic $ 110,514 $ 97,718 $ 89,988 Foreign 91 (476 ) 82 Income from operations before income taxes and equity method investments $ 110,605 $ 97,242 $ 90,070 The provision (benefit) for income taxes was comprised of the following components (in thousands): Year Ended 2018 2017 2016 Federal $ 11,602 $ 5,340 $ 13,454 State 4,937 2,523 2,394 Foreign 133 38 (45 ) Current provision 16,672 7,901 15,803 Federal 8,010 (28,013 ) 17,170 State 3,586 3,313 2,831 Deferred provision (benefit) 11,596 (24,700 ) 20,001 Federal 234 (60 ) (1,573 ) State 28 — (445 ) Non-current provision (benefit) resulting from allocating tax benefits directly to additional paid in capital and changes in liabilities 262 (60 ) (2,018 ) Provision (benefit) for income taxes $ 28,530 $ (16,859 ) $ 33,786 For the years ended December 31, 2018 , 2017 and 2016 the non-current benefits related to liabilities for uncertain tax positions was $0.3 million , $0.1 million and $0.2 million , respectively. The schedule of effective income tax rate reconciliation is as follows: Year Ended 2018 2017 2016 Statutory U.S. Federal tax rate 21.0 % 35.0 % 35.0 % Increase (decrease) in tax rate resulting from: State taxes—net of Federal benefit 6.1 % 3.9 % 3.4 % Stock-based compensation (2.2 )% (2.8 )% — % Excess executive compensation 0.8 % 0.4 % 0.7 % ESSP 0.4 % (1.5 )% (0.7 )% Net deferred tax liability remeasurement — % (52.0 )% — % Section 199 deductions — % (0.4 )% (0.4 )% Other, net (0.3 )% 0.1 % (0.5 )% Effective tax rate 25.8 % (17.3 )% 37.5 % We received an income taxes refund, net of payments of $4.3 million for the year ended December 31, 2018 . We paid income taxes, net of refunds, of $15.9 million and $18.1 million for the years ended December 31, 2017 and 2016 , respectively. Deferred income taxes arise from temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements. A summary of the tax effect of the significant components of deferred income taxes is as follows (in thousands): December 31, 2018 2017 Goodwill and other assets $ 114,532 $ 100,967 Property and equipment 8,168 7,303 Unbilled receivables - IRC Section 481(a) 8,816 11,693 Gross deferred tax liabilities 131,516 119,963 Retirement and other liabilities (20,707 ) (20,636 ) Allowance for potential contract losses and other contract reserves (1,681 ) (1,598 ) Foreign and state operating loss carryforwards (1,709 ) (1,252 ) Less: Valuation allowance 1,537 717 Gross deferred tax assets (22,560 ) (22,769 ) Net deferred tax liabilities $ 108,956 $ 97,194 The Tax Cuts and Jobs Act of 2017 (TCJA) was enacted on December 22, 2017, TCJA reduced the U.S. federal corporate tax rate from 35% to 21% effective January 1, 2018. At December 31, 2017 , we made a reasonable estimate of the effects on our existing deferred tax balances and effective tax rate for the deductibility of officer's compensation, the acquisition of InfoZen and assets that qualify for an immediate deduction. Our accounting for those items, as impacted by the TCJA, is now complete and no material adjustments were required. The re-measurement of the deferred taxes at December 31, 2017 due to the decrease in the federal corporate tax rate resulted in a decrease to income tax expense of $50.6 million and reduced the 2017 effective tax rate by 52.0% . After the 2017 corporate tax return was filed the adjustment related to the re-measurement of the deferred taxes changed by an immaterial amount. At December 31, 2018 , we had state and foreign net operating losses of approximately $10.3 million and $5.7 million , respectively. The state net operating losses expire beginning 2020 through 2036 . We recorded a full valuation allowance against the foreign net operating losses and a partial valuation allowance against the state net operating losses, as we do not believe those losses will be fully utilized in the future. A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows (in thousands): December 31, 2018 2017 2016 Gross unrecognized tax benefits at beginning of year $ 220 $ 293 $ 519 Lapse in statute of limitations (86 ) (105 ) (285 ) Increases in tax positions for prior years 36 — — Increases in tax positions for current year 320 32 59 Gross unrecognized tax benefits at end of year $ 490 $ 220 $ 293 The total liability for gross unrecognized tax benefits as of December 31, 2018 , 2017 and 2016 includes $0.4 million , $0.2 million and $0.2 million , respectively, of unrecognized net tax benefits which, if ultimately recognized, would reduce our annual effective tax rate in a future period. We are subject to income taxes in the U.S., various state and foreign jurisdictions. Tax statutes and regulations within each jurisdiction are subject to interpretation and require significant judgment to apply. We are no longer subject to U.S. federal or non-U.S. income tax examinations by tax authorities for the years before 2014. We are no longer subject to U.S. state tax examinations by tax authorities for the years before 2013. We believe it is reasonably possible that no gross unrecognized tax benefits will be settled within the next year due to expirations of statute of limitations.

Quarterly Financial Information

Quarterly Financial Information (Unaudited) (Notes)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited) [Text Block]	Quarterly Financial Information (Unaudited) The quarterly financial data reflects, in our opinion, all normal and recurring adjustments to present fairly the results of operations for such periods. Results of any one or more quarters are not necessarily indicative of annual results or continuing trends. The following tables set forth selected unaudited quarterly financial data: 2018 March 31, June 30, September 30, December 31, (in thousands, except per share data) Revenues $ 473,236 $ 491,044 $ 497,205 $ 497,072 Operating income $ 26,421 $ 28,329 $ 29,399 $ 28,593 Income from operations before income taxes and equity method investments $ 25,706 $ 27,757 $ 28,827 $ 28,315 Net income $ 20,067 $ 19,915 $ 21,923 $ 20,192 Class A common stock: Basic weighted average common shares outstanding 26,115 26,339 26,421 26,536 Basic earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.51 Diluted weighted average common shares outstanding 26,525 26,627 26,743 26,812 Diluted earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.50 Class B common stock: Basic weighted average common shares outstanding 13,189 13,189 13,189 13,188 Basic earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.51 Diluted weighted average common shares outstanding 13,189 13,189 13,189 13,188 Diluted earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.50 2017 March 31, June 30, September 30, December 31, (in thousands, except per share data) Revenues $ 418,374 $ 413,694 $ 422,665 $ 462,285 Operating income $ 24,390 $ 24,935 $ 23,140 $ 25,729 Income from operations before income taxes and equity method investments $ 24,159 $ 24,651 $ 23,114 $ 25,318 Net income $ 15,028 $ 15,561 $ 15,182 $ 68,370 Class A common stock: Basic weighted average common shares outstanding 25,547 25,618 25,684 25,886 Basic earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.75 Diluted weighted average common shares outstanding 25,778 25,827 25,929 26,353 Diluted earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.73 Class B common stock: Basic weighted average common shares outstanding 13,191 13,191 13,191 13,189 Basic earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.75 Diluted weighted average common shares outstanding 13,191 13,191 13,191 13,189 Diluted earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.73

Schedule II

Schedule II	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	SCHEDULE II Valuation and Qualifying Accounts Activities in our allowance accounts for the years ended December 31, 2018 , 2017 and 2016 were as follows (in thousands): Doubtful Accounts Balance at Beginning of Period Charged to Costs and Expenses Deductions Other* Balance at End of Period 2016 $ 8,473 — (215 ) (750 ) $ 7,508 2017 $ 7,508 — — (1,351 ) $ 6,157 2018 $ 6,157 — — 76 $ 6,233 * Other represents doubtful account reserves released or recorded as part of net revenues for estimated customer disallowances. Deferred Tax Asset Valuation Balance at Beginning of Period Charged to Costs and Expenses Deductions Other Balance at End of Period 2016 $ — 272 — — $ 272 2017 $ 272 444 — 1 $ 717 2018 $ 717 820 — — $ 1,537

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Principles of Consolidation [Policy Text Block]	Principles of Consolidation - Our consolidated financial statements include the accounts of ManTech International Corporation, subsidiaries we control and variable interest entities that are required to be consolidated. All intercompany accounts and transactions have been eliminated.
Use of Accounting Estimates [Policy Text Block]	Use of Accounting Estimates - We prepare our consolidated financial statements in conformity with U.S. GAAP, which requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates involve judgments with respect to, among other things, various future economic factors that are difficult to predict and are beyond the control of us. Therefore, actual amounts could differ from these estimates.
Revenue Recognition [Policy Text Block]	Revenue Recognition - On January 1, 2018, we adopted Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers using the modified retrospective method applied to those contracts that were not substantially complete as of January 1, 2018. ASC 606 outlines a five-step model whereby revenue is recognized as performance obligations within the contract are satisfied. ASC 606 also requires new, expanded disclosures regarding revenue recognition. We recognized the cumulative effect of adopting ASC 606 as an increase to the 2018 opening balance of retained earnings in the pretax amount of $0.8 million , with the impact primarily related to fixed-price contracts. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts were not adjusted and continue to be reported in accordance with ASC 605, Revenue Recognition . Revenue for the year ended December 31, 2018 increased $2.4 million as a result of applying ASC 606. We account for a contract when: both we and the customer approve and commit; our rights and those of the customer 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, referred to as performance obligations. Then we determine the transaction price for the contract; the consideration to which we can expect in exchange for the promised goods or services in the contract. 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 at 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 distinct performance obligation using our best estimate of the standalone selling price for 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. We recognize revenue over time when there is a continuous transfer of control to our customer. For our U.S. government contracts, this continuous transfer of control to the customer 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. We typically use a cost-based input method to measure progress. Contract costs include labor, material and allocable indirect expenses. Revenue is recognized proportionally as contract costs are incurred plus estimated fees. For time-and-material contracts, we bill the customer per labor hour and per material, and revenue is recognized in the amount invoiced since the amount corresponds directly to the value of our performance to date. For stand-ready service contracts, a time-elapsed output method is used to measure progress, and revenue is recognized straight-line 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 transfer when we have a present right to payment and our customer has legal title. Determining a measure of progress and when control transfers requires us to make judgments that affect the timing of when revenue is recognized. Essentially, all of our contracts satisfy their performance obligations over time. Contracts are often modified to account for changes in contract specifications and requirements. Contract modifications impact performance obligations when the modification either creates new or changes the existing enforceable rights and obligations. The effect of a contract modification on the transaction price and our measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenue and profit cumulatively. Furthermore, a significant change in one or more estimates could affect the profitability of our contracts. We recognize adjustments in estimated profit on contracts in the period identified. The impact of adjustments in contract estimates can be reflected in either revenue or operating expenses on our consolidated statement of income. We have an 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 assumptions and 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 year ended December 31, 2018 , the aggregate impact of adjustments in contract estimates increased our revenue by $9.8 million . No adjustment on any one contract was material to our consolidated financial statements for the year ended December 31, 2018 . Results for prior periods were reported in accordance with ASC 605. Revenue for cost-reimbursable contracts were recorded as reimbursable costs were incurred, including an estimated share of the applicable contractual fees earned. For performance-based fees under cost-reimbursable contracts, we recognized the relevant portion of the expected fee to be awarded by the customer at the time such fee can be reasonably estimated, based on factors such as our prior award experience and communications with the customer regarding performance, or upon approval by the customer. For time-and-materials contracts, revenue was recognized to the extent of billable rates times hours delivered plus materials and other reimbursable costs incurred. For long-term fixed-price contracts, revenue was recognized at a rate per unit as the units were delivered or by other methods to measure services provided. Revenue from other long-term fixed-price contracts were recognized ratably over the contract period or by other appropriate methods to measure services provided. Contract costs were expensed as incurred except for certain limited long-term contracts noted below. For long-term contracts, specifically described in the scope section of ASC 605-35, Revenue Recognition - Construction-Type and Production-Type Contracts , we applied the percentage of completion method. Under the percentage of completion method, income was recognized at a consistent profit margin over the period of performance based on estimated profit margins at completion of the contract. This method of accounting required estimating the total revenue and total contract cost at completion of the contract. These estimates were periodically reviewed and revisions were made as required using the cumulative catch-up method. The impact on revenue and contract profit as a result of these revisions were included in the periods in which the revisions were made. Estimated losses on contracts at completion were recognized when identified. In certain circumstances, revenue was recognized when contract amendments were not finalized.
Contract Assets [Policy Test Block]	Contract Assets - Amounts are invoiced as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Generally, revenue recognition occurs before billing, resulting in contract assets. These contract assets are referred to as unbilled receivables and are reported within receivables, net on our consolidated balance sheet.
Billed Receivables [Policy Text Block]	Billed Receivables - Amounts billed and due from our customers are classified as billed receivables and are reported within receivables, net on the 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.
Contract Liabilities [Policy Text Block]	Contract Liabilities - We receive advances and milestone payments from our customers on selected contracts that exceed revenue earned to date, resulting in contract liabilities. Contract liabilities 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. Contract liabilities are reported on our consolidated balance sheet on a net contract basis at the end of each reporting period.
Contract Costs [Policy Text Block]	Contract Costs - Contract costs include direct labor, direct materials, overhead and, when applicable, general and administrative expenses. Incremental costs of obtaining a contract that we expect to recover are recognized as deferred contract costs and are amortized on a systematic basis that is consistent with the transfer to the customer of the goods or services. Other incremental costs are expensed when incurred. Costs of fulfilling a contract that relate directly to a contract or to an anticipated contract that can be specifically identified, generate or enhance resources that will be used in satisfying future performance obligations and are expected to be recovered are recognized as deferred contract costs and amortized on a systematic basis that is consistent with the transfer of the goods or services to the customer. Other costs of fulfilling a contract (costs of wasted materials, labor or other resources to fulfill the contracts that were not reflected in the price of the contract and costs that relate to satisfied performance obligations in the contract) are expensed when incurred.
Deferred Contract Costs [Policy Text Block]	Deferred Contract Costs - Costs of obtaining or fulfilling a contract that meet the criteria in ASC 340, Other Assets and Deferred Costs , are capitalized and amortized on a systematic basis that is consistent with the transfer of goods or services to the customer. Deferred contracts costs are reported on our consolidated balance sheet within current or non-current other assets based on the expected life of the related contract. At December 31, 2018 , we had $7.8 million of deferred contract costs related to the fulfillment of future contract obligations. For the year ended December 31, 2018 we recorded amortization expense of $0.5 million .
General and Administrative Expenses [Policy Text Block]	General and Administrative Expenses - General and administrative expenses include the salaries and wages, plus associated fringe benefits of our employees not performing work directly for customers, and associated facilities costs. Among the functions covered by these costs are corporate business development, bid and proposal, contracts administration, finance and accounting, legal, corporate governance and executive and senior management. In addition, we include stock-based compensation, as well as depreciation and amortization expenses related to the general and administrative function. We recognize interest related to unrecognized tax benefits within interest expense and penalties related to unrecognized tax benefits in general and administrative expenses. We classify indirect costs incurred as cost of services and general and administrative expenses in the same manner as such costs are defined in our disclosure statements under U.S. Government Cost Accounting Standards.
Cash and Cash Equivalents [Policy Text Block]	Cash and Cash Equivalents - For the purpose of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks and short-term investments with maturity dates of three months or less at the date of purchase.
Property and Equipment [Policy Text Block]	Property and Equipment - Property and equipment are recorded at original cost to us. Upon sale or retirement, the costs and related accumulated depreciation or amortization are eliminated from the respective accounts and any resulting gain or loss is included in income. Maintenance and repairs are charged to expense as incurred.
Depreciation and Amortization Method [Policy Text Block]	Depreciation and Amortization Method - Furniture and office equipment are depreciated using the straight-line method with estimated useful lives ranging from one to seven years . Leasehold improvements are amortized using the straight-line method over the shorter of the asset's useful life or the term of the lease.
Goodwill [Policy Text Block]	Goodwill - The purchase price of an acquired business is allocated to the tangible assets, financial assets and separately recognized intangible assets acquired less liabilities assumed based upon their respective fair values, with the excess recorded as goodwill. We review goodwill at least annually for impairment, or whenever events or circumstances indicate that the carrying value of long-lived assets may not be fully recoverable.
Other Intangible Assets [Policy Text Block]	Other Intangible Assets - Contract rights and other intangible assets are amortized primarily using the pattern of benefits method over periods ranging from one to twenty-five years . We account for the cost of computer software developed or obtained for internal use in accordance with ASC 350-985 , Intangibles - Goodwill and Other - Software . These capitalized software costs are included in other intangible assets, net. We account for software development costs related to software products for sale, lease or otherwise marketed in accordance with ASC 985-20 , Software - Costs of Software to Be Sold, Leased, or Marketed . For projects fully funded by us, development costs are capitalized from the point of demonstrated technological feasibility until the point in time that the product is available for general release to customers. Once the product is available for general release, capitalized costs are amortized based on units sold or on a straight-line basis over a five -year period or other such shorter period as may be required.
Impairment of Long-Lived Assets [Policy Text Block]	Impairment of Long-Lived Assets - Whenever events or changes in circumstances indicate that the carrying amount of long-lived assets may not be fully recoverable, we evaluate the probability that future undiscounted net cash flows will be less than the carrying amount of the assets. If any impairment were indicated as a result of this review, we would recognize a loss based on the amount by which the carrying amount exceeds the estimated fair value.
Employee Supplemental Savings Plan Assets [Policy Text Block]	Employee Supplemental Savings Plan (ESSP) Assets - We maintain several non-qualified defined contribution supplemental retirement plans for certain key employees that are accounted for in accordance with ASC 710-10-05 , Compensation - General - Deferred Compensation - Rabbi Trust , as the underlying assets are held in rabbi trusts with investments directed by the respective employee. A rabbi trust is a grantor trust generally set up to fund compensation for a select group of management and the assets of this trust are available to satisfy the claims of general creditors in the event of bankruptcy of us. The assets held by the rabbi trusts are recorded at cash surrender value in our consolidated financial statements as ESSP assets with a related liability to employees recorded as a deferred compensation liability in accrued retirement.
Stock-based Compensation [Policy Text Block]	Stock-based Compensation - We account for stock-based compensation in accordance with ASC 718 , Compensation - Stock Compensation , which requires the use of a valuation model to calculate the fair value of stock-based awards. We have elected to use the Black-Scholes-Merton pricing model to determine fair value of stock options on the dates of grant for our stock options. The fair value is included in operating expenses or capitalized, as appropriate, straight-line over the period in which service is provided in exchange for the award. The grant date fair value of the restricted stock is equal to the closing market price of our common stock on the date of grant. The compensation expense for restricted stock is recognized over the service period and is based on the grant date fair value of the shares. The grant date fair value of the restricted stock unit (RSU) is equal to the closing market price of our common stock on the grant date less the present value of dividends expected to be awarded during the service period. We recognize the grant date fair value of RSUs of shares we expect to issue as compensation expense ratably over the requisite service period. We account for forfeitures as they occur.
Income Taxes [Policy Text Block]	Income Taxes - We account for income taxes in accordance with ASC 740 , Income Taxes . Under this method, deferred income taxes are determined based on the estimated future tax effects of differences between the financial statement and tax bases of assets and liabilities given the provisions of enacted tax laws. Deferred income tax provisions and benefits are based on changes to the assets or liabilities from year-to-year. In providing for deferred taxes, we consider tax regulations of the jurisdictions in which we operate, estimates of future taxable income and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies vary, adjustments to the carrying value of deferred tax assets and liabilities may be required. Valuation allowances are recorded related to deferred tax assets based on the “more likely than not” criteria. We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain the position following an audit. For tax positions meeting the “more likely than not” threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
Foreign-Currency Translation [Policy Text Block]	Foreign-Currency Translation - All assets and liabilities of foreign subsidiaries are translated into U.S. dollars at fiscal year-end exchange rates. Income and expense items are translated at average monthly exchange rates prevailing during the fiscal year. The resulting translation adjustments are recorded as a component of accumulated other comprehensive income (loss).
Comprehensive Income (Loss) [Policy Text Block]	Comprehensive Income (Loss) - Comprehensive income (loss) consists of net income; translation adjustments, net of tax; and actuarial gain (loss) on defined benefit pension plan, net of tax.
Fair Value of Financial Instruments [Policy Text Block]	Fair Value of Financial Instruments - The carrying value of our cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate their fair value because of the short-term nature of these amounts.
Variable Interest Entities [Policy Text Block]	Variable Interest Entities (VIEs) - We determine whether we have a controlling financial interest in a VIE. The reporting entity with a variable interest or interest that provides the reporting entity with a controlling financial interest in a VIE will have both (a) the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and (b) the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. We have one entity that has been consolidated as a VIE. The purpose of the entity is to perform on certain U.S. Navy contracts. These contracts ended in 2018. The maximum amount of loss we were exposed to as of December 31, 2018 was not material to our consolidated financial statements.
Investments [Policy Text Block]	Investments - Investments where we have the ability to exercise significant influence, but we do not control, are accounted for under the equity method of accounting and are included in other assets on our consolidated balance sheets. Significant influence typically exists if we have a 20% to 50% ownership interest in the investee. Under this method of accounting, our share of the net earnings or losses of the investee is included in equity in earnings or losses of unconsolidated subsidiaries on our consolidated statement of income. Investments where we have less than 20% ownership interest in the investee and lack the ability to exercise significant influence are accounted for under the cost method. Under the cost method, we recognize our investment in the stock of an investee as an asset. The investment is measured initially at cost. We recognize as income dividends received that are distributed from net accumulated earnings. Dividends received in excess of earnings are considered a return of investment and are recorded as reductions of costs of the investment. Impairment is assessed at the individual investment level. An investment is impaired if the fair value of the investment is less than its costs. If it is determined that the impairment is other than temporary, then an impairment loss is recognized in earnings. The fair value of the investment would become the new cost basis of the investment and will not be adjusted for subsequent recoveries in fair value.
Business Combinations Policy [Policy Text Block]	Business Combinations - The accounting for our business combinations consists of allocating the purchase price to tangible and intangible assets acquired and liabilities assumed based on their estimated fair values, with the excess recorded as goodwill. We have up to one year from the acquisition date to use information as of each acquisition date to adjust the fair value of the acquired assets and liabilities, which may result in material changes to their recorded values with an offsetting adjustment to goodwill.
Recently Adopted ASUs [Text Block]	Recently Adopted ASUs ASU 2014-09, Revenue from Contracts with Customers (ASC 606) , supersedes existing revenue recognition guidance, including ASC 605-35, Revenue Recognition - Construction-Type and Production-Type Contracts . ASU 2014-09 outlines a single set of comprehensive principles for recognizing revenue under GAAP. Among other things, it requires companies to identify contractual performance obligations and determine whether revenue should be recognized at a point in time or over time. It also requires new, expanded disclosures regarding revenue recognition. We elected to adopt using the modified retrospective method that applied to those contracts that were not substantially completed as of January 1, 2018. Additional details are included in the revenue recognition policy above and Note 3 below. ASU 2017-09, Compensation—Stock Compensation (ASC 718): Scope of Modification Accounting , provides guidance concerning which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in ASC 718. Specifically, an entity is to account for the effects of a modification, unless all of the following are satisfied: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and (3) the classification of the modified award as an equity instrument or as a liability instrument is the same as the classification of the original award immediately before the original award is modified. The current disclosure requirements in ASC 718 apply regardless of whether an entity is required to apply modification accounting under the amendments in ASU 2017-09. The adoption of this ASU on January 1, 2018 did not have an effect on our consolidated financial statements. ASU 2017-01, Business Combinations (ASC 805)—Clarifying the Definition of a Business , clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. Under the guidance in Topic 805, there are three elements of a business: inputs, processes and outputs. While an integrated set of assets and activities (collectively, a “set”) that is a business usually has outputs, outputs are not required to be present. Additionally, all of the inputs and processes that a seller uses in operating a set are not required if market participants can acquire the set and continue to produce outputs. The amendments in ASU 2017-01 provide a screen to determine when a set is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This screen reduces the number of transactions that need to be further evaluated. If, however, the screen is not met, then the amendments in this ASU (1) require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs and (2) remove the evaluation of whether a market participant could replace missing elements. Finally, the amendments in this ASU narrow the definition of the term “output” so that the term is consistent with the manner in which outputs are described in ASC 606. The adoption of this ASU on January 1, 2018 did not have an effect on our consolidated financial statements. ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . This ASU addresses the following eight specific cash flow issues: Debt prepayment or debt extinguishment costs; settlement of zero coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies (including bank-owned life insurance policies); distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. We applied the equity method of accounting for applicable investments. We made an accounting policy election to classify distributions received from equity method investees using the cumulative earnings approach. Distributions received are considered returns on investment and classified as cash inflows from operating activities, unless the investor’s cumulative distributions received less distributions received in prior periods that were determined to be returns of investment exceed cumulative equity in earnings recognized by the investor (as adjusted for amortization of basis differences). When such an excess occurs, the current-period distribution up to this excess is considered a return of investment and should be classified as cash inflows from investing. Due to the adoption of ASU 2016-15 on January 1, 2018, we classified proceeds from settlements of corporate-owned life insurance policies as investing activities on our consolidated statement of cash flows for the year ended December 31, 2018 .
Recently Issued But Not Yet Adopted ASUs [Policy,Text Block]	Recently Issued But Not Yet Adopted ASUs The FASB has issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 , which resolves the diversity in practice concerning the manner in which entities account for transactions on the basis of their view of the economics of the collaborative arrangement. A collaborative arrangement, as defined by the guidance in Topic 808, is a contractual arrangement under which two or more parties actively participate in a joint operating activity and are exposed to significant risks and rewards that depend on the activity’s commercial success. In particular, the amendments in ASU 2018-18 (1) clarify that certain transactions between collaborative participants should be accounted for as revenue under Topic 606 when the collaborative participant is a customer in the context of the unit of account, and that, in those situations, all the guidance in Topic 606 should be applied, including recognition, measurement, presentation, and disclosure requirements; (2) add unit-of-account guidance in Topic 808 to align with the guidance in Topic 606 (i.e., a distinct good or service), limited to when an entity is assessing whether the collaborative arrangement or a part of the arrangement is within the scope of Topic 606; and (3) clarify that in a transaction that is not directly related to sales to third parties, presenting the transaction as revenue would be precluded if the collaborative participant counterparty was not a customer. The amendments are effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. Note that early adoption is permitted, including adoption in any interim period for public business entities for periods for which financial statements have not yet been issued. We are currently evaluating the effect on our consolidated financial statements. The FASB issued ASU 2016-02, Leases (Topic 842) . The amendments in this ASU create Topic 842, Leases , and supersede the leases requirements in Topic 840, Leases . The objective of Topic 842 is to establish the principles that lessees and lessors should apply to report useful information to users of financial statements about the amount, timing and uncertainty of cash flows arising from a lease. This ASU is effective for public entities for annual periods after December 15, 2018, and interim periods therein. Early adoption is permitted for all entities. We developed and substantially completed a detailed implementation plan which includes; implementing a software platform for lease accounting; updating our policies and controls; and developing disclosures. We will adopt ASU 2016-02 retrospectively at the beginning of the period of adoption, January 1, 2019, through a cumulative adjustment to retained earnings and the recognition of a lease liability and corresponding right of use asset. We will elect the following transition related practical expedients; not to reassess whether any expired or existing contracts are or contain leases, not to reassess lease classification as determined under ASC 840 and, not to reassess initial direct costs for any existing lease. We have also elected not to apply the recognition and measurement requirements to short-term leases (less than 1 year). We expect the adoption of ASU 2016-02 to have a material effect on our consolidated financial statements resulting from the recognition of a lease liability of approximately $125 million and right of use asset of approximately $115 million as well as significant additional disclosures required under the ASU. The adoption will not impact financial covenant calculations required under our existing credit agreement. The FASB has issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement , which focuses on improving the effectiveness of disclosures in the notes to financial statements by facilitating clear communication of the information required by GAAP that is most important to users of each entity’s financial statements. The amendments in ASU 2018-13 modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement . Specifically, the amendments in this ASU remove disclosure requirements in Topic 820 related to (1) the amount of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy; (2) the policy for timing of transfers between levels; (3) the valuation processes for Level 3 fair value measurements. Additionally, the ASU adds disclosure requirements for public entities about (1) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period, and (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendments are effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2019. The amendments regarding changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Note that early application is permitted for all entities; moreover, an entity is allowed to early adopt any removed or modified disclosures upon issuance of this ASU and delay adoption of the additional disclosures until their effective date. We do not expect the adoption of this ASU to have a material effect on our consolidated financial statements. The FASB has issued ASU 2018-17, Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities , which reduces the cost and complexity of financial reporting associated with consolidation of variable interest entities (VIEs). Specially, the indirect interests held through related parties in common control arrangements should be considered on a proportional basis (as opposed to a direct interest in its entirety) for determining whether fees paid to decision makers and service providers are variable interests. This is consistent with how indirect interests held through related parties under common control are considered for determining whether a reporting entity must consolidate a VIE. The amendments are effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. We do not expect the adoption of this ASU to have a material effect on our consolidated financial statements. The FASB has 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 (a consensus of the FASB Emerging Issues Task Force) , which aims to reduce complexity in the accounting for costs of implementing a cloud computing service arrangement. In fact, ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Accordingly, the amendments in this ASU require an entity (customer) in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40, Intangibles—Goodwill and Other—Internal-Use Software, in order to determine which implementation costs to capitalize as an asset related to the service contract and which costs to expense. Costs to develop or obtain internal-use software that cannot be capitalized under Subtopic 350-40 (e.g., training costs and certain data conversion costs) also cannot be capitalized for a hosting arrangement that is a service contract. Additionally, the amendments in this ASU require the entity (customer) to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement (i.e., the noncancellable period of the arrangement plus periods covered by (1) an option to extend the arrangement if the customer is reasonably certain to exercise that option, (2) an option to terminate the arrangement if the customer is reasonably certain not to exercise the termination option, and (3) an option to extend (or not to terminate) the arrangement in which exercise of the option is in the control of the vendor. The amendments in this ASU also require the entity to present the expense related to the capitalized implementation costs in the same line item in the statement of income as the fees associated with the hosting element (service) of the arrangement, and to classify payments for capitalized implementation costs in the statement of cash flows in the same manner as payments made for fees associated with the hosting element. Note that the accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this ASU. The amendments are effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. We are currently evaluating methods of adoption as well as the effect on our consolidated financial statements. The FASB has issued ASU 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting which supersedes the guidance in Subtopic 505-50, Equity—Equity-Based Payments to Non-Employees . In particular, ASU 2018-07 expands the scope of topic 718, Compensation—Stock Compensation (which previously only included payments to employees), to include share-based payment transactions for acquiring goods and services from non-employees. In fact, an entity should now apply the requirements of Topic 718 to non-employee awards, except for specific guidance on inputs to an option pricing model and the attribution of cost (i.e., the period of time over which share-based payment awards vest and the pattern of cost recognition over that period). Additionally, the amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in the grantor’s own operations by issuing share-based payment awards, and clarify that Topic 718 does not apply to share-based payments used to effectively provide (1) financing to the issuer, or (2) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Topic 606, Revenue from Contracts with Customers . The amendments are effective for fiscal years beginning after December 15, 2019, and for interim periods with fiscal years beginning after December 15, 2020. Early adoption is permitted, including adoption in any interim period, for reporting periods for which financial statements have not yet been issued. We do not expect the adoption of this ASU to have a material effect on our consolidated financial statements. The FASB has issued ASU 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which helps organizations reclassify certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017 (TCJA), enacted on December 22, 2017. Specifically, this ASU allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the TCJA, eliminating the stranded tax effects resulting from the TCJA and improving the usefulness of information reported to financial statement users. Because the amendments only relate to the reclassification of the income tax effects of the TCJA, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. Additionally it requires financial statement preparers to disclose (1) a description of their accounting policy for releasing income tax effects from accumulated other comprehensive income, (2) whether they elect to reclassify the stranded income tax effects from the TCJA and (3) information about other income tax effects related to the application of the TCJA that are reclassified from accumulated other comprehensive income to retained earnings, if any. The amendments are effective for annual periods, and for interim periods within those annual periods, beginning after December 15, 2018. Early adoption is permitted, including adoption in any interim period, for reporting periods for which financial statements have not yet been issued. We do not expect the adoption of this ASU to have a material effect on our consolidated financial statements. The FASB has issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment , which simplifies the manner in which an entity determines the amount of a goodwill impairment by eliminating Step 2 from the goodwill impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. In computing the implied fair value of goodwill under Step 2, an entity, prior to the amendments in ASU 2017-04, had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities, including unrecognized assets and liabilities, in accordance with the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Under the amendments in this ASU, an entity should (1) perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and (2) recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the understanding that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Public entities should adopt the amendments in this ASU prospectively for their annual, or any interim periods, in fiscal years beginning after December 15, 2019. Early adoption is permitted for all entities for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We do not expect the adoption of this ASU to have a material effect on our consolidated financial statements. Other ASUs effective after December 31, 2018 are not expected to have a material effect on our consolidated financial statements.

Revenue from Contract with Cu_2

Revenue from Contract with Customers (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue by Contract Type [Table Text Block]	Year Ended December 31, 2018 2017 2016 Cost-reimbursable $ 1,325,024 $ 1,130,134 $ 1,085,429 Fixed-price 435,599 370,517 306,735 Time-and-materials 197,934 216,367 209,432 $ 1,958,557 $ 1,717,018 $ 1,601,596
Revenue by Customer [Table Text Block]	Year Ended December 31, 2018 2017 2016 Department of Defense and intelligence agencies $ 1,436,627 $ 1,359,309 $ 1,331,551 Federal civilian agencies 476,834 315,036 230,399 State agencies, international agencies and commercial entities 45,096 42,673 39,646 $ 1,958,557 $ 1,717,018 $ 1,601,596
Revenue by Contractor Type [Table Text Block]	Year Ended December 31, 2018 2017 2016 Prime contractor $ 1,742,097 $ 1,514,924 $ 1,404,490 Subcontractor 216,460 202,094 197,106 $ 1,958,557 $ 1,717,018 $ 1,601,596
Revenue From External Customers by Geographic Location [Table Text Block]	Year Ended December 31, 2018 2017 2016 U.S $ 1,928,785 $ 1,688,671 $ 1,576,290 International 29,772 28,347 25,306 $ 1,958,557 $ 1,717,018 $ 1,601,596
Schedule Of Contract Receivables [Table Text Block]	The components of contract receivables are as follows (in thousands): December 31, 2018 January 1, 2018 December 31, 2017 Billed receivables $ 301,716 $ 236,113 $ 236,113 Unbilled receivables 109,895 88,767 81,454 Allowance for doubtful accounts (6,233 ) (6,157 ) (6,157 ) Receivables-net $ 405,378 $ 318,723 $ 311,410
Contract with Customer, Asset and Liability [Table Text Block]	The following table discloses contract liabilities (in thousands): December 31, 2018 January 1, 2018 December 31, 2017 Contract liabilities $ 28,209 $ 22,156 $ 18,816
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	The following table discloses when we expect to recognize the remaining performance obligation as revenue (in billions): For the year ending December 31, 2019 December 31, 2020 Thereafter Total Revenue expected to be recognized $ 1.6 $ 0.8 $ 0.4 $ 2.8

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2018
InfoZen, LLC [Member]
Business Combination Segment Allocation [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table represents the purchase price allocation for InfoZen (in thousands): Cash and cash equivalents $ 1,406 Receivables 8,991 Prepaid expenses 4,046 Other current assets 7 Goodwill 129,932 Other intangible assets 54,850 Property and equipment 485 Other assets 111 Accounts payable and accrued expenses (7,488 ) Accrued salaries and related expenses (3,092 ) Contract liabilities (5,258 ) Net assets acquired and liabilities assumed $ 183,990

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The net income available to common stockholders and weighted average number of common shares outstanding used to compute basic and diluted earnings per share for each class of common stock are as follows (in thousands, except per share amounts): Year Ended 2018 2017 2016 Distributed earnings $ 39,627 $ 32,709 $ 32,138 Undistributed earnings 42,470 81,432 24,253 Net income $ 82,097 $ 114,141 $ 56,391 Class A common stock: Basic net income available to common stockholders $ 54,715 $ 75,413 $ 36,885 Basic weighted average common shares outstanding 26,354 25,685 24,944 Basic earnings per share $ 2.08 $ 2.94 $ 1.48 Diluted net income available to common stockholders $ 54,937 $ 75,698 $ 36,988 Effect of potential exercise of stock options 324 288 202 Diluted weighted average common shares outstanding 26,678 25,973 25,146 Diluted earnings per share $ 2.06 $ 2.91 $ 1.47 Class B common stock: Basic net income available to common stockholders $ 27,382 $ 38,728 $ 19,506 Basic weighted average common shares outstanding 13,189 13,190 13,192 Basic earnings per share $ 2.08 $ 2.94 $ 1.48 Diluted net income available to common stockholders $ 27,160 $ 38,443 $ 19,403 Diluted weighted average common shares outstanding 13,189 13,190 13,192 Diluted earnings per share $ 2.06 $ 2.91 $ 1.47

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment [Table Text Block]	Major classes of property and equipment are summarized as follows (in thousands): December 31, 2018 2017 Furniture and equipment $ 97,577 $ 79,218 Leasehold improvements 43,065 39,022 Property and equipment-gross 140,642 118,240 Accumulated depreciation and amortization (89,215 ) (72,158 ) Property and equipment-net $ 51,427 $ 46,082

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table Text Block]	The changes in the carrying amounts of goodwill during fiscal years 2018 and 2017 were as follows (in thousands): Goodwill Balance Goodwill at December 31, 2016 $ 955,874 Acquisitions 128,686 Goodwill at December 31, 2017 1,084,560 Acquisition fair value adjustment 1,246 Goodwill at December 31, 2018 $ 1,085,806
Schedule of Other Intangible Assets [Table Text Block]	Other intangible assets consisted of the following (in thousands): December 31, 2018 December 31, 2017 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Other intangible assets: Contract and program intangible assets $ 355,932 $ 201,298 $ 154,634 $ 355,932 $ 179,049 $ 176,883 Capitalized software cost for internal use 50,925 33,597 17,328 46,995 29,530 17,465 Total other intangible assets-net $ 406,857 $ 234,895 $ 171,962 $ 402,927 $ 208,579 $ 194,348
Schedule of Other Intangible Assets, Future Amortization Expense [Table Text Block]	We estimate that we will have the following amortization expense for the future periods indicated below (in thousands): Year ending: December 31, 2019 $ 22,621 December 31, 2020 $ 21,781 December 31, 2021 $ 19,051 December 31, 2022 $ 16,456 December 31, 2023 $ 13,485

Commitments and Contingencies_2

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	At December 31, 2018 , our aggregate future minimum rental commitments under these leases are as follows (in thousands): Total Year ending: December 31, 2019 $ 33,953 December 31, 2020 28,954 December 31, 2021 25,794 December 31, 2022 21,852 December 31, 2023 18,353 Thereafter 9,296 Total $ 138,202

Stockholders Equity and Stock_2

Stockholders Equity and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following table summarizes weighted-average assumptions used in our calculations of fair value for the years ended December 31, 2018 , 2017 and 2016 : Year Ended 2018 2017 2016 Volatility 26.57 % 25.59 % 23.70 % Expected life of options 3 years 3 years 3 years Risk-free interest rate 2.72 % 1.72 % 1.10 % Dividend yield 2.00 % 2.75 % 2.88 %
Share-based Compensation, Stock Options, Activity [Table Text Block]	The following table summarizes stock option activity for the years ended December 31, 2018 , 2017 and 2016 : Number of Shares Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Life Stock options outstanding at December 31, 2015 2,495,310 $ 30.86 $ 3,583 Granted 199,938 $ 34.22 Exercised (1,045,789 ) $ 29.24 $ 8,858 Cancelled and expired (489,040 ) $ 37.91 Stock options outstanding at December 31, 2016 1,160,419 $ 29.93 $ 14,299 Granted 534,030 $ 42.90 Exercised (463,800 ) $ 29.34 $ 7,203 Cancelled and expired (61,241 ) $ 33.80 Stock options outstanding at December 31, 2017 1,169,408 $ 35.88 $ 16,731 Granted 466,828 $ 54.87 Exercised (420,524 ) $ 30.05 $ 12,411 Cancelled and expired (122,312 ) $ 43.85 Stock options outstanding at December 31, 2018 1,093,400 $ 45.34 $ 8,776 4 years Stock options exercisable at December 31, 2018 318,998 $ 35.57 $ 5,336 2 years
Schedule of Non-Vested Share Activity [Table Text Block]	The following table summarizes non-vested stock options for the year ended December 31, 2018 : Number of Shares Weighted Average Fair Value Non-vested stock options at December 31, 2017 684,979 $ 6.23 Granted 466,828 $ 10.42 Vested (257,293 ) $ 5.83 Cancelled (120,112 ) $ 7.04 Non-vested stock options at December 31, 2018 774,402 $ 8.77
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Restricted Stock Activity [Table Text Block]	The following table summarizes the restricted stock activity during the years ended December 31, 2018 and 2017 : Number of Shares Weighted Average Fair Value Non-vested restricted stock at December 31, 2016 18,000 $ 33.84 Granted 24,000 $ 37.90 Vested (18,000 ) $ 33.84 Non-vested restricted stock at December 31, 2017 24,000 $ 37.90 Granted 24,000 $ 52.83 Vested (28,000 ) $ 40.03 Non-vested restricted stock at December 31, 2018 20,000 $ 52.83
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Restricted Stock Activity [Table Text Block]	The following table summarizes the RSU activity during the years ended December 31, 2018 and 2017 : Number of Units Weighted Average Fair Value RSUs at December 31, 2016 206,338 $ 30.10 Granted 55,830 $ 35.34 Vested (3,300 ) $ 30.60 Forfeited (97,525 ) $ 31.00 RSUs at December 31, 2017 161,343 $ 31.36 Granted 76,713 $ 53.97 Vested (87,200 ) $ 28.40 Forfeited (13,260 ) $ 38.98 RSUs at December 31, 2018 137,596 $ 45.11

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	The domestic and foreign components of income operations before income taxes and equity method investments were as follows (in thousands): Year Ended 2018 2017 2016 Domestic $ 110,514 $ 97,718 $ 89,988 Foreign 91 (476 ) 82 Income from operations before income taxes and equity method investments $ 110,605 $ 97,242 $ 90,070
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The provision (benefit) for income taxes was comprised of the following components (in thousands): Year Ended 2018 2017 2016 Federal $ 11,602 $ 5,340 $ 13,454 State 4,937 2,523 2,394 Foreign 133 38 (45 ) Current provision 16,672 7,901 15,803 Federal 8,010 (28,013 ) 17,170 State 3,586 3,313 2,831 Deferred provision (benefit) 11,596 (24,700 ) 20,001 Federal 234 (60 ) (1,573 ) State 28 — (445 ) Non-current provision (benefit) resulting from allocating tax benefits directly to additional paid in capital and changes in liabilities 262 (60 ) (2,018 ) Provision (benefit) for income taxes $ 28,530 $ (16,859 ) $ 33,786
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The schedule of effective income tax rate reconciliation is as follows: Year Ended 2018 2017 2016 Statutory U.S. Federal tax rate 21.0 % 35.0 % 35.0 % Increase (decrease) in tax rate resulting from: State taxes—net of Federal benefit 6.1 % 3.9 % 3.4 % Stock-based compensation (2.2 )% (2.8 )% — % Excess executive compensation 0.8 % 0.4 % 0.7 % ESSP 0.4 % (1.5 )% (0.7 )% Net deferred tax liability remeasurement — % (52.0 )% — % Section 199 deductions — % (0.4 )% (0.4 )% Other, net (0.3 )% 0.1 % (0.5 )% Effective tax rate 25.8 % (17.3 )% 37.5 %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	A summary of the tax effect of the significant components of deferred income taxes is as follows (in thousands): December 31, 2018 2017 Goodwill and other assets $ 114,532 $ 100,967 Property and equipment 8,168 7,303 Unbilled receivables - IRC Section 481(a) 8,816 11,693 Gross deferred tax liabilities 131,516 119,963 Retirement and other liabilities (20,707 ) (20,636 ) Allowance for potential contract losses and other contract reserves (1,681 ) (1,598 ) Foreign and state operating loss carryforwards (1,709 ) (1,252 ) Less: Valuation allowance 1,537 717 Gross deferred tax assets (22,560 ) (22,769 ) Net deferred tax liabilities $ 108,956 $ 97,194
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows (in thousands): December 31, 2018 2017 2016 Gross unrecognized tax benefits at beginning of year $ 220 $ 293 $ 519 Lapse in statute of limitations (86 ) (105 ) (285 ) Increases in tax positions for prior years 36 — — Increases in tax positions for current year 320 32 59 Gross unrecognized tax benefits at end of year $ 490 $ 220 $ 293

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Table Text Block]	The following tables set forth selected unaudited quarterly financial data: 2018 March 31, June 30, September 30, December 31, (in thousands, except per share data) Revenues $ 473,236 $ 491,044 $ 497,205 $ 497,072 Operating income $ 26,421 $ 28,329 $ 29,399 $ 28,593 Income from operations before income taxes and equity method investments $ 25,706 $ 27,757 $ 28,827 $ 28,315 Net income $ 20,067 $ 19,915 $ 21,923 $ 20,192 Class A common stock: Basic weighted average common shares outstanding 26,115 26,339 26,421 26,536 Basic earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.51 Diluted weighted average common shares outstanding 26,525 26,627 26,743 26,812 Diluted earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.50 Class B common stock: Basic weighted average common shares outstanding 13,189 13,189 13,189 13,188 Basic earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.51 Diluted weighted average common shares outstanding 13,189 13,189 13,189 13,188 Diluted earnings per share $ 0.51 $ 0.50 $ 0.55 $ 0.50 2017 March 31, June 30, September 30, December 31, (in thousands, except per share data) Revenues $ 418,374 $ 413,694 $ 422,665 $ 462,285 Operating income $ 24,390 $ 24,935 $ 23,140 $ 25,729 Income from operations before income taxes and equity method investments $ 24,159 $ 24,651 $ 23,114 $ 25,318 Net income $ 15,028 $ 15,561 $ 15,182 $ 68,370 Class A common stock: Basic weighted average common shares outstanding 25,547 25,618 25,684 25,886 Basic earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.75 Diluted weighted average common shares outstanding 25,778 25,827 25,929 26,353 Diluted earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.73 Class B common stock: Basic weighted average common shares outstanding 13,191 13,191 13,191 13,189 Basic earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.75 Diluted weighted average common shares outstanding 13,191 13,191 13,191 13,189 Diluted earnings per share $ 0.39 $ 0.40 $ 0.39 $ 1.73

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	Jan. 02, 2018USD ($)	Dec. 31, 2018USD ($)Entities	Jan. 01, 2019USD ($)
Accounting Policies [Line Items]
Impact to Revenue, Result of ASC 606		$ 2.4
Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price		9.8
Deferred Contract Costs		7.8
Deferred Contract Cost, Amortization Expense		$ 0.5
More Likely Than Not Threshold		50.00%
Number of Consolidated Variable Interest Entities | Entities		1
Minimum [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life		1 year
Equity Method Investment, Ownership Percentage		20.00%
Maximum [Member]
Accounting Policies [Line Items]
Maturity Threshold For Including In Cash And Cash Equivalent		3 months
Property, Plant and Equipment, Useful Life		7 years
Equity Method Investment, Ownership Percentage		50.00%
Other Intangible Assets [Member] | Minimum [Member]
Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life		1 year
Other Intangible Assets [Member] | Maximum [Member]
Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life		25 years
Capitalized Software Cost For Sale [Member]
Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life		5 years
Less than [Member]
Accounting Policies [Line Items]
Cost Method Investment, Ownership Percentage		20.00%
Accounting Standards Update 2014-09 [Member]
Accounting Policies [Line Items]
Cumulative Effect on Retained Earnings, before Tax	$ 0.8
Liabilities, Total [Member] | Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ 125
Assets, Total [Member] | Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ 115

Revenue from Contract with Cu_3

Revenue from Contract with Customers Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)Entities
Additional Revenue [Line Items]
Number of Reportable Segments | Entities	1
Contract Receivable, Due after Next Rolling Twelve Months	$ 0.8
Percentage of Accounts Receivable Not Expected to be Collected Within One Year related to Receivables from Direct Sales to U.S. Government	94.00%
Concentration Credit Risk, Percentage, Accounts Receivable	12.00%
Contract with Customer, Liability, Revenue Recognized	$ 18.2
Revenue, Remaining Performance Obligation, Amount	$ 2,800

Revenue from Contract with Cu_4

Revenue from Contract with Customers Revenue by Contract Type (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue by Contract Type [Line Items]
Revenues	$ 497,072	$ 497,205	$ 491,044	$ 473,236	$ 462,285	$ 422,665	$ 413,694	$ 418,374	$ 1,958,557	$ 1,717,018	$ 1,601,596
Cost-reimbursable
Revenue by Contract Type [Line Items]
Revenues									1,325,024	1,130,134	1,085,429
Fixed-price
Revenue by Contract Type [Line Items]
Revenues									435,599	370,517	306,735
Time-and-materials
Revenue by Contract Type [Line Items]
Revenues									$ 197,934	$ 216,367	$ 209,432

Revenue from Contract with Cu_5

Revenue from Contract with Customers Revenue by Customer (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue by Customer [Line Items]
Revenues	$ 497,072	$ 497,205	$ 491,044	$ 473,236	$ 462,285	$ 422,665	$ 413,694	$ 418,374	$ 1,958,557	$ 1,717,018	$ 1,601,596
Department of Defense and intelligence agencies
Revenue by Customer [Line Items]
Revenues									1,436,627	1,359,309	1,331,551
Federal civilian agencies
Revenue by Customer [Line Items]
Revenues									476,834	315,036	230,399
State agencies, international agencies and commercial entities
Revenue by Customer [Line Items]
Revenues									$ 45,096	$ 42,673	$ 39,646

Revenue from Contract with Cu_6

Revenue from Contract with Customers Revenue by Contractor Type (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue by Contract Type [Line Items]
Revenues	$ 497,072	$ 497,205	$ 491,044	$ 473,236	$ 462,285	$ 422,665	$ 413,694	$ 418,374	$ 1,958,557	$ 1,717,018	$ 1,601,596
Prime contractor
Revenue by Contract Type [Line Items]
Revenues									1,742,097	1,514,924	1,404,490
Subcontractor
Revenue by Contract Type [Line Items]
Revenues									$ 216,460	$ 202,094	$ 197,106

Revenue from Contract with Cu_7

Revenue from Contract with Customers Revenue by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue From External Customers by Geographic Location [Line Items]
Revenues	$ 497,072	$ 497,205	$ 491,044	$ 473,236	$ 462,285	$ 422,665	$ 413,694	$ 418,374	$ 1,958,557	$ 1,717,018	$ 1,601,596
U.S
Revenue From External Customers by Geographic Location [Line Items]
Revenues									1,928,785	1,688,671	1,576,290
International
Revenue From External Customers by Geographic Location [Line Items]
Revenues									$ 29,772	$ 28,347	$ 25,306

Revenue from Contract with Cu_8

Revenue from Contract with Customers Schedule of Contract Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Billed receivables	$ 301,716	$ 236,113	$ 236,113
Unbilled receivables	109,895	88,767	81,454
Allowance for doubtful accounts	(6,233)	(6,157)	(6,157)
Receivables-net	$ 405,378	$ 318,723	$ 311,410

Revenue from Contract with Cu_9

Revenue from Contract with Customers Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract liabilities	$ 28,209	$ 22,156	$ 18,816

Revenue from Contract with C_10

Revenue from Contract with Customers Revenue, Remaining Performance Obligation (Details) $ in Billions	Dec. 31, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 2.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Amount	$ 1.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Amount	$ 0.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Revenue, Remaining Performance Obligation, Amount	$ 0.4

Acquisitions (Narrative) (Detai

Acquisitions (Narrative) (Details) - InfoZen, LLC [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed		$ 0.8
Business Combination, Consideration Transferred	$ 184
Expected Goodwill Tax Amortization Period	15 years
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	18 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Asset, Amount	$ 49.2
Finite-Lived Intangible Asset, Useful Life	20 years
Backlog [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Asset, Amount	$ 5.7
Finite-Lived Intangible Asset, Useful Life	1 year

Acquisitions (Schedule of Recog

Acquisitions (Schedule of Recognized Identified Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 1,085,806	$ 1,084,560	$ 955,874
InfoZen, LLC [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	1,406
Receivables	8,991
Prepaid expenses	4,046
Other current assets	7
Goodwill	129,932
Other intangible assets	54,850
Property and equipment	485
Other assets	111
Accounts payable and accrued expenses	(7,488)
Accrued salaries and related expenses	(3,092)
Contract liabilities	(5,258)
Net assets acquired and liabilities assumed	$ 183,990

Earnings per Share (Narrative)

Earnings per Share (Narrative) (Details) - $ / shares	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Dividend Declared And Paid	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount													293,898	265,866	369,300
Exercised, Number of Shares													420,524	463,800	1,045,789

(Schedule of Earnings Per Share

(Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of Earnings Per Share, Basic and Diluted [Line Items]
Distributed earnings									$ 39,627	$ 32,709	$ 32,138
Undistributed earnings									42,470	81,432	24,253
Net income	$ 20,192	$ 21,923	$ 19,915	$ 20,067	$ 68,370	$ 15,182	$ 15,561	$ 15,028	82,097	114,141	56,391
Class A Common Stock [Member]
Components of Earnings Per Share, Basic and Diluted [Line Items]
Basic net income available to common stockholders									$ 54,715	$ 75,413	$ 36,885
Basic weighted average common shares outstanding	26,536	26,421	26,339	26,115	25,886	25,684	25,618	25,547	26,354	25,685	24,944
Basic earnings per share	$ 0.51	$ 0.55	$ 0.50	$ 0.51	$ 1.75	$ 0.39	$ 0.40	$ 0.39	$ 2.08	$ 2.94	$ 1.48
Diluted net income available to common stockholders									$ 54,937	$ 75,698	$ 36,988
Effect of potential exercise of stock options									324	288	202
Diluted weighted average common shares outstanding	26,812	26,743	26,627	26,525	26,353	25,929	25,827	25,778	26,678	25,973	25,146
Diluted earnings per share	$ 0.50	$ 0.55	$ 0.50	$ 0.51	$ 1.73	$ 0.39	$ 0.40	$ 0.39	$ 2.06	$ 2.91	$ 1.47
Common Stock, Class B
Components of Earnings Per Share, Basic and Diluted [Line Items]
Basic net income available to common stockholders									$ 27,382	$ 38,728	$ 19,506
Basic weighted average common shares outstanding	13,188	13,189	13,189	13,189	13,189	13,191	13,191	13,191	13,189	13,190	13,192
Basic earnings per share	$ 0.51	$ 0.55	$ 0.50	$ 0.51	$ 1.75	$ 0.39	$ 0.40	$ 0.39	$ 2.08	$ 2.94	$ 1.48
Diluted net income available to common stockholders									$ 27,160	$ 38,443	$ 19,403
Diluted weighted average common shares outstanding	13,188	13,189	13,189	13,189	13,189	13,191	13,191	13,191	13,189	13,190	13,192
Diluted earnings per share	$ 0.50	$ 0.55	$ 0.50	$ 0.51	$ 1.73	$ 0.39	$ 0.40	$ 0.39	$ 2.06	$ 2.91	$ 1.47

Property and Equipment (Propert

Property and Equipment (Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment-gross	$ 140,642	$ 118,240
Accumulated depreciation and amortization	(89,215)	(72,158)
Property and equipment-net	51,427	46,082
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment-gross	97,577	79,218
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment-gross	$ 43,065	$ 39,022

Property and Equipment (Narrati

Property and Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation and Amortization Expense	$ 25.5	$ 9.5	$ 7.8

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of Intangible Assets	$ 26.3	$ 23.5	$ 21.8

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill balance, period start	$ 1,084,560	$ 955,874
Acquisitions		128,686
Acquisition fair value adjustment	1,246
Goodwill balance, period end	$ 1,085,806	$ 1,084,560

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets (Schedule of Other Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 406,857	$ 402,927
Accumulated Amortization	234,895	208,579
Net Carrying Amount	171,962	194,348
Contract and program intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	355,932	355,932
Accumulated Amortization	201,298	179,049
Net Carrying Amount	154,634	176,883
Capitalized software cost for internal use
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	50,925	46,995
Accumulated Amortization	33,597	29,530
Net Carrying Amount	$ 17,328	$ 17,465

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets (Schedule of Other Intangible Assets, Future Amortization Expense) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Year ending:
December 31, 2019	$ 22,621
December 31, 2020	21,781
December 31, 2021	19,051
December 31, 2022	16,456
December 31, 2023	$ 13,485

Debt (Revolving Credit Facility

Debt (Revolving Credit Facility) (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt, Weighted Average Interest Rate	3.91%	2.99%
Bank of America Syndicate [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 500,000,000
Long-term Line of Credit	7,500,000	$ 31,000,000
Line of Credit Facility, Weighted Average Borrowings	34,200,000	2,700,000
Line of Credit Facility, Maximum Available Borrowing	482,900,000
Bank of America Syndicate [Member] | Letter of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	75,000,000
Letters of Credit Outstanding, Amount	9,600,000	$ 15,300,000
Bank of America Syndicate [Member] | Revolving Credit Facility, Swing Line Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 30,000,000
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.25%
Bank of America's Base Rate [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Bank of America's Base Rate [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%

Commitments and Contingencies_3

Commitments and Contingencies (Pending Litigation) (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Loss Contingency, Damages Paid, Value	$ 1,400,000
Loss Contingency, Loss in Period	$ 0

Commitments and Contingencies_4

Commitments and Contingencies (Letter of Credit) (Narrative) (Details) - Bank of America Syndicate [Member] - Letter of Credit [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 9.6	$ 15.3
Performance Guarantee [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 9.5

Commitments and Contingencies_5

Commitments and Contingencies (Operating Leases) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Rent Expense, Net	$ 39.9	$ 36.9	$ 37.4
Deferred Rent Credit	$ 13.2	$ 10.6

Commitments and Contingencies_6

Commitments and Contingencies (Schedule of Future Minimum Rental Payments for Operating Leases) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Year ending:
December 31, 2019	$ 33,953
December 31, 2020	28,954
December 31, 2021	25,794
December 31, 2022	21,852
December 31, 2023	18,353
Thereafter	9,296
Total	$ 138,202

Stockholders Equity and Stock_3

Stockholders Equity and Stock-Based Compensation (Narrative) (Details) - USD ($)	Jan. 02, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders Equity and Stock-Based Compensation [Line Items]
Treasury Stock, Shares		244,113	244,113
Class B Share Convertible to Class A Share		1
Preferred Stock, Shares Authorized		20,000,000
Preferred Stock, Par Value Per Share		$ 0.01
Preferred Stock, Shares Outstanding		0	0
Stock-based Compensation Arrangement by Stock-based Payment Award, Number of Shares Authorized		14,551,899
Stock-based Compensation Arrangement by Stock-based Payment Award, Number of Shares Available for Issuance		6,113,209
Stock-based Compensation Expense		$ 5,100,000	$ 6,300,000	$ 3,300,000
Employee Services Stock-based Compensation Expense, Capitalized Amount		0	0	0
Income tax expense (benefit) related to the exercise of stock options and vested cancellations and the vesting of restricted stock		$ (3,100,000)	$ (2,700,000)
Tax deficiency from the exercise of stock options				$ (100,000)
Stock-based Compensation Arrangement by Stock-based Award, Award Vesting Period		3 years	3 years	3 years
Stock-based Compensation Arrangement by Stock-based Payment Award, Expiration Period		5 years	5 years	5 years
Expected Annual Cash Dividend		$ 1	$ 0.84	$ 0.84
Granted, Weighted Average Fair Value		$ 10.42	$ 6.75	$ 4.60
Stock-based Payment Award, Options, Vested, Fair Value		$ 1,500,000	$ 1,700,000	$ 2,600,000
Employee Service Stock-based Compensation, Nonvested Awards, Compensation Cost Not Yet Recognized		$ 5,600,000
Stock-based Compensation, Nonvested Awards, Total Compensation Cost Not Yet Recognized, Period for Recognition		2 years
Performance-based restricted stock units [Member]
Stockholders Equity and Stock-Based Compensation [Line Items]
Stock-based Compensation Arrangement by Stock-based Award, Award Vesting Period		2 years	2 years
RSU Performance Factor, Number of Shares Issued		1.5
Class A Common Stock [Member]
Stockholders Equity and Stock-Based Compensation [Line Items]
Common Stock, Shares Authorized		150,000,000	150,000,000
Common Stock, Par Value Per Share		$ 0.01	$ 0.01
Common Stock, Shares Outstanding		26,573,400	26,041,660
Common Stock, Voting Rights		1
Common Stock, Class B
Stockholders Equity and Stock-Based Compensation [Line Items]
Common Stock, Shares Authorized		50,000,000	50,000,000
Common Stock, Par Value Per Share		$ 0.01	$ 0.01
Common Stock, Shares Outstanding		13,188,045	13,189,245
Common Stock, Voting Rights		10
Maximum [Member]
Stockholders Equity and Stock-Based Compensation [Line Items]
Stock-based Compensation Arrangement by Stock-based Payment Award, Expiration Period		8 years	8 years	8 years
Going Private Transaction [Member] | Class A Common Stock [Member]
Stockholders Equity and Stock-Based Compensation [Line Items]
Common Stock, Voting Rights		1
Going Private Transaction [Member] | Common Stock, Class B
Stockholders Equity and Stock-Based Compensation [Line Items]
Common Stock, Voting Rights		1
Subsequent Event [Member]
Stockholders Equity and Stock-Based Compensation [Line Items]
Annual Percentage Increase In Number Of Shares Available For Issuance	1.50%
Stock-based Compensation Arrangement by Stock-based Payment Award, Number of Additional Shares Authorized	596,422
Director [Member] | Restricted Stock [Member]
Stockholders Equity and Stock-Based Compensation [Line Items]
Stock-based Compensation Arrangement by Stock-based Award, Award Vesting Period		1 year	1 year

Stockholders Equity and Stock_4

Stockholders Equity and Stock-Based Compensation (Schedule of Shared-based Payment Award, Stock Options, Valuation Assumptions) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders Equity and Stock-Based Compensation [Abstract]
Volatility	26.57%	25.59%	23.70%
Expected life of options	3 years	3 years	3 years
Risk-free interest rate	2.72%	1.72%	1.10%
Dividend yield	2.00%	2.75%	2.88%

Stockholders Equity and Stock_5

Stockholders Equity and Stock-Based Compensation (Schedule of Share-based Compensation, Stock Options, Activity) (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock options, Number of Shares, Period Start	1,169,408	1,160,419	2,495,310
Granted, Number of Shares	466,828	534,030	199,938
Exercised, Number of Shares	(420,524)	(463,800)	(1,045,789)
Cancelled and expired, Number of Shares	(122,312)	(61,241)	(489,040)
Stock options, Number of Shares, Period End	1,093,400	1,169,408	1,160,419
Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Stock options, Weighted Average Exercise Price, Period Start	$ 35.88	$ 29.93	$ 30.86
Granted, Weighted Average Exercise Price	54.87	42.90	34.22
Exercised, Weighted Average Exercise Price	30.05	29.34	29.24
Cancelled and expired, Weighted Average Exercise Price	43.85	33.80	37.91
Stock options, Weighted Average Exercise Price, Period End	$ 45.34	$ 35.88	$ 29.93
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Stock options, Aggregate Intrinsic Value	$ 8,776	$ 16,731	$ 14,299	$ 3,583
Exercised, Aggregate Intrinsic Value	$ 12,411	$ 7,203	$ 8,858
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number	318,998
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price	$ 35.57
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	$ 5,336
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	2 years

Stockholders Equity and Stock_6

Stockholders Equity and Stock-Based Compensation (Schedule of Non-Vested Share Activity) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested [Roll Forward]
Non-vested stock options, Number of Shares, Period Start	684,979
Granted, Number of Shares	466,828	534,030	199,938
Vested, Number of Shares	(257,293)
Cancelled, Number of Shares	(120,112)
Non-vested stock options, Number of Shares, Period End	774,402	684,979
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Non-vested stock options, Weighted Average Fair Value, Period Start	$ 6.23
Granted, Weighted Average Fair Value	10.42	$ 6.75	$ 4.60
Vested, Weighted Average Fair Value	5.83
Cancelled, Weighted Average Fair Value	7.04
Non-vested stock options, Weighted Average Fair Value, Period End	$ 8.77	$ 6.23

Stockholders Equity and Stock_7

Stockholders Equity and Stock-Based Compensation (Schedule of Share-based Compensation, Restricted Stock Activity) (Details) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Restricted Stock, Non-vested
Non-vested, Period Start	24,000	18,000
Granted	24,000	24,000
Vested	(28,000)	(18,000)
Non-vested, Period End	20,000	24,000
Share-based Compensation Arrangement by Share-based Payment Award, Restricted Stock, Weighted Average Fair Value
Non-vested, Weighted Average Fair Value, Period Start	$ 37.90	$ 33.84
Granted, Weighted Average Fair Value	52.83	37.90
Vested, Weighted Average Fair Value	40.03	33.84
Non-vested, Weighted Average Fair Value, Period End	$ 52.83	$ 37.90

Stockholders Equity and Stock_8

Stockholders Equity and Stock-Based Compensation Schedule of Share-based Compensation, Restricted Stock Unit Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Restricted Stock Units, Number of Shares [Roll Forward]
Non-vested, Period Start	161,343	206,338
Granted	76,713	55,830
Vested	(87,200)	(3,300)
Forfeited	(13,260)	(97,525)
Non-vested, Period End	137,596	161,343
Share-based Compensation Arrangement by Share-based Payment Award, Restricted Stock Units, Weighted Average Fair Value
Non-vested, Weighted Average Fair Value, Period Start	$ 31.36	$ 30.10
Granted, Weighted Average Fair Value	53.97	35.34
Vested, Weighted Average Fair Value	28.40	30.60
Forfeited, Weighted Average Fair Value	38.98	31
Non-vested, Weighted Average Fair Value, Period End	$ 45.11	$ 31.36

Retirement Plans (Narrative) (D

Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Plan [Line Items]
Defined Contribution Plan, Other Than Employee Stock Ownership Plan, Contributions	$ 23.5	$ 20.6	$ 19.8
Employee Supplemental Savings Plan (ESSP) Percentage of Annual Base Compensation	75.00%	75.00%	75.00%
Employee Supplemental Savings Plan (ESSP) Percentage of Bonus	100.00%	100.00%	100.00%
Employee Supplemental Savings Plan (ESSP), Employee Contribution	$ 3.4	$ 3	$ 2.6
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	100.00%	100.00%
Defined Benefit Plan, Benefit Obligation	$ 0.8	$ 1.2

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Non-current Provision (Benefit) for Income Taxes related to Liabilities for Uncertain Tax Positions	$ (300,000)	$ (100,000)	$ (200,000)
Income Taxes Refund, Net of Payments	$ 4,300,000
Income Taxes Paid, Net of Refunds		$ 15,900,000	$ 18,100,000
Statutory U.S. Federal tax rate	21.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Deduction in Income Tax, Deferred Tax Liability Remeasurement		$ 50,600,000
Effective Income Tax Rate Reconciliation, Deduction, Deferred Tax Liability Remeasurement	0.00%	52.00%	0.00%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 400,000	$ 200,000	$ 200,000
Settlement With Taxing Authority [Member]
Income Tax Contingency [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	0
State [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	10,300,000
Foreign Tax Authority [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	$ 5,700,000

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income before Income Tax, Domestic and Foreign) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Domestic									$ 110,514	$ 97,718	$ 89,988
Foreign									91	(476)	82
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND EQUITY METHOD INVESTMENTS	$ 28,315	$ 28,827	$ 27,757	$ 25,706	$ 25,318	$ 23,114	$ 24,651	$ 24,159	$ 110,605	$ 97,242	$ 90,070

Income Taxes (Schedule of Compo

Income Taxes (Schedule of Components of Income Tax Expense) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal	$ 11,602,000	$ 5,340,000	$ 13,454,000
State	4,937,000	2,523,000	2,394,000
Foreign	133,000	38,000	(45,000)
Current provision	16,672,000	7,901,000	15,803,000
Federal	8,010,000	(28,013,000)	17,170,000
State	3,586,000	3,313,000	2,831,000
Deferred provision (benefit)	11,596,000	(24,700,000)	20,001,000
Federal	234,000	(60,000)	(1,573,000)
State	28,000	0	(445,000)
Non-current provision (benefit) resulting from allocating tax benefits directly to additional paid in capital and changes in liabilities	262,000	(60,000)	(2,018,000)
Provision (benefit) for income taxes	$ 28,530,000	$ (16,859,000)	$ 33,786,000

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory U.S. Federal tax rate	21.00%	35.00%	35.00%
Increase (decrease) in tax rate resulting from:
State taxes—net of Federal benefit	6.10%	3.90%	3.40%
Stock-based compensation	(2.20%)	(2.80%)	0.00%
Excess executive compensation	0.80%	0.40%	0.70%
ESSP	0.40%	(1.50%)	(0.70%)
Net deferred tax liability remeasurement	0.00%	(52.00%)	0.00%
Section 199 deductions	0.00%	(0.40%)	(0.40%)
Other, net	(0.30%)	0.10%	(0.50%)
Effective tax rate	25.80%	(17.30%)	37.50%

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Goodwill and other assets	$ 114,532	$ 100,967
Property and equipment	8,168	7,303
Unbilled receivables - IRC Section 481(a)	8,816	11,693
Gross deferred tax liabilities	131,516	119,963
Retirement and other liabilities	(20,707)	(20,636)
Allowance for potential contract losses and other contract reserves	(1,681)	(1,598)
Foreign and state operating loss carryforwards	(1,709)	(1,252)
Less: Valuation allowance	1,537	717
Gross deferred tax assets	(22,560)	(22,769)
Net deferred tax liabilities	$ 108,956	$ 97,194

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Gross unrecognized tax benefits at beginning of year	$ 220,000	$ 293,000	$ 519,000
Lapse in statute of limitations	(86,000)	(105,000)	(285,000)
Increases in tax positions for prior years	36,000	0	0
Increases in tax positions for current year	320,000	32,000	59,000
Gross unrecognized tax benefits at end of year	$ 490,000	$ 220,000	$ 293,000

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Line Items]
Revenues	$ 497,072	$ 497,205	$ 491,044	$ 473,236	$ 462,285	$ 422,665	$ 413,694	$ 418,374	$ 1,958,557	$ 1,717,018	$ 1,601,596
Operating income	28,593	29,399	28,329	26,421	25,729	23,140	24,935	24,390	112,742	98,194	90,963
Income from operations before income taxes and equity method investments	28,315	28,827	27,757	25,706	25,318	23,114	24,651	24,159	110,605	97,242	90,070
Net income	$ 20,192	$ 21,923	$ 19,915	$ 20,067	$ 68,370	$ 15,182	$ 15,561	$ 15,028	$ 82,097	$ 114,141	$ 56,391
Class A Common Stock [Member]
Quarterly Financial Information Disclosure [Line Items]
Basic weighted average common shares outstanding	26,536	26,421	26,339	26,115	25,886	25,684	25,618	25,547	26,354	25,685	24,944
Basic earnings per share	$ 0.51	$ 0.55	$ 0.50	$ 0.51	$ 1.75	$ 0.39	$ 0.40	$ 0.39	$ 2.08	$ 2.94	$ 1.48
Diluted weighted average common shares outstanding	26,812	26,743	26,627	26,525	26,353	25,929	25,827	25,778	26,678	25,973	25,146
Diluted earnings per share	$ 0.50	$ 0.55	$ 0.50	$ 0.51	$ 1.73	$ 0.39	$ 0.40	$ 0.39	$ 2.06	$ 2.91	$ 1.47
Common Stock, Class B
Quarterly Financial Information Disclosure [Line Items]
Basic weighted average common shares outstanding	13,188	13,189	13,189	13,189	13,189	13,191	13,191	13,191	13,189	13,190	13,192
Basic earnings per share	$ 0.51	$ 0.55	$ 0.50	$ 0.51	$ 1.75	$ 0.39	$ 0.40	$ 0.39	$ 2.08	$ 2.94	$ 1.48
Diluted weighted average common shares outstanding	13,188	13,189	13,189	13,189	13,189	13,191	13,191	13,191	13,189	13,190	13,192
Diluted earnings per share	$ 0.50	$ 0.55	$ 0.50	$ 0.51	$ 1.73	$ 0.39	$ 0.40	$ 0.39	$ 2.06	$ 2.91	$ 1.47

Schedule II (Valuation and Qual

Schedule II (Valuation and Qualifying Accounts) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 6,157,000	$ 7,508,000	$ 8,473,000
Charged to Costs and Expenses		0	0	0
Deductions		0	0	(215,000)
Other	[1]	76,000	(1,351,000)	(750,000)
Balance at End of Period		6,233,000	6,157,000	7,508,000
Deferred Tax Asset Valuation
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		717,000	272,000	0
Charged to Costs and Expenses		820,000	444,000	272,000
Deductions		0	0	0
Other		0	1,000	0
Balance at End of Period		$ 1,537,000	$ 717,000	$ 272,000
[1]	Other represents doubtful account reserves released or recorded as part of net revenues for estimated customer disallowances.