Booz Allen Hamilton Holding (BAH) 10-Q 1 Nov 19 2020 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Sep. 30, 2019	Oct. 29, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-34972
Entity Registrant Name	Booz Allen Hamilton Holding Corp
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-2634160
Entity Address, Address Line One	8283 Greensboro Drive,
Entity Address, City or Town	McLean,
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	22102
City Area Code	703
Local Phone Number	902-5000
Title of 12(b) Security	Class A Common Stock
Trading Symbol	BAH
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		140,380,260
Current Fiscal Year End Date	--03-31
Entity Central Index Key	0001443646
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019
Current assets:
Cash and cash equivalents	$ 781,546	$ 283,990
Accounts receivable, net of allowance	1,321,111	1,330,364
Prepaid expenses and other current assets	60,746	84,986
Total current assets	2,163,403	1,699,340
Property and equipment, net of accumulated depreciation	187,475	172,453
Operating lease right-of-use assets	250,810	0
Intangible assets, net of accumulated amortization	294,300	287,051
Goodwill	1,581,160	1,581,160
Other long-term assets	91,710	91,837
Total assets	4,568,858	3,831,841
Current liabilities:
Current portion of long-term debt	77,924	57,924
Accounts payable and other accrued expenses	684,374	664,948
Accrued compensation and benefits	290,751	325,553
Operating lease liabilities	32,994
Other current liabilities	124,526	130,814
Total current liabilities	1,210,569	1,179,239
Long-term debt, net of current portion	2,044,821	1,701,837
Operating lease liabilities, net of current portion	282,718
Other long-term liabilities	190,567	275,399
Total liabilities	3,728,675	3,156,475
Commitments and contingencies (Note 18)
Stockholders’ equity:
Common stock, Class A — $0.01 par value — authorized, 600,000,000 shares; issued, 160,400,357 shares at September 30, 2019 and 159,924,825 shares at March 31, 2019; outstanding, 140,373,450 shares at September 30, 2019 and 140,027,853 shares at March 31, 2019	1,604	1,599
Treasury stock, at cost — 20,026,907 shares at September 30, 2019 and 19,896,972 shares at March 31, 2019	(719,793)	(711,450)
Additional paid-in capital	427,817	401,596
Retained earnings	1,161,674	994,811
Accumulated other comprehensive loss	(31,119)	(11,190)
Total stockholders’ equity	840,183	675,366
Total liabilities and stockholders’ equity	$ 4,568,858	$ 3,831,841

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2019	Mar. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	600,000,000	600,000,000
Common stock, issued (in shares)	160,400,357	159,924,825
Common stock, outstanding (in shares)	140,373,450	140,027,853
Treasury stock (in shares)	20,026,907	19,896,972

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 1,819,577	$ 1,613,997	$ 3,644,753	$ 3,260,845
Operating costs and expenses:
Cost of revenue	843,942	748,570	1,684,596	1,534,382
Billable expenses	539,846	478,349	1,091,021	955,784
General and administrative expenses	244,122	226,901	478,402	432,737
Depreciation and amortization	19,632	16,426	39,653	32,579
Total operating costs and expenses	1,647,542	1,470,246	3,293,672	2,955,482
Operating income	172,035	143,751	351,081	305,363
Interest expense	(25,863)	(22,247)	(51,050)	(45,321)
Other income (expense), net	2,005	(1,617)	3,976	(2,788)
Income before income taxes	148,177	119,887	304,007	257,254
Income tax expense	33,852	27,174	72,296	60,337
Net income	$ 114,325	$ 92,713	$ 231,711	$ 196,917
Earnings per common share (Note 4):
Basic (in dollars per share)	$ 0.81	$ 0.65	$ 1.64	$ 1.37
Diluted (in dollars per share)	$ 0.80	$ 0.64	$ 1.63	$ 1.36

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 114,325	$ 92,713	$ 231,711	$ 196,917
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Change in unrealized (loss) gain on derivatives designated as cash flow hedges	(5,014)		(19,979)
Change in unrealized (loss) gain on derivatives designated as cash flow hedges		1,038		2,958
Change in postretirement plan costs	16	424	50	831
Total other comprehensive income (loss), net of tax	(4,998)	1,462	(19,929)	3,789
Comprehensive income	$ 109,327	$ 94,175	$ 211,782	$ 200,706

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net income	$ 231,711	$ 196,917
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	39,653	32,579
Noncash lease expense	27,711
Stock-based compensation expense	15,808	13,265
Amortization of debt issuance costs and loss on extinguishment	2,459	6,920
Losses on dispositions	581	408
Changes in assets and liabilities:
Accounts receivable, net of allowance	9,253	(31,621)
Deferred income taxes and income taxes receivable / payable	(30,322)	(14,677)
Prepaid expenses and other current assets	(16,696)	(17,633)
Other long-term assets	(95)	(6,217)
Accrued compensation and benefits	(28,805)	(3,154)
Accounts payable and other accrued expenses	34,623	80,703
Other current liabilities	2,311	13,803
Operating lease liabilities	(24,529)
Other long-term liabilities	3,016	3,274
Net cash provided by operating activities	266,679	274,567
Cash flows from investing activities
Purchases of property, equipment, and software	(59,978)	(39,672)
Payments for business acquisitions, net of cash acquired	0	(20)
Net cash used in investing activities	(59,978)	(39,692)
Cash flows from financing activities
Proceeds from issuance of common stock	7,049	5,227
Stock option exercises	3,687	8,541
Repurchases of common stock	(14,658)	(98,377)
Cash dividends paid	(64,848)	(54,659)
Repayment of debt	(38,962)	(101,550)
Proceeds from debt issuance	400,000	62,072
Other financing activities	(1,413)	(501)
Net cash provided by (used in) financing activities	290,855	(179,247)
Net increase in cash and cash equivalents	497,556	55,628
Cash and cash equivalents––beginning of period	283,990	286,958
Cash and cash equivalents––end of period	781,546	342,586
Net cash paid during the period for:
Interest	44,965	38,140
Income taxes	102,151	74,275
Supplemental disclosures of non-cash investing and financing activities
Noncash financing activities	$ 2,110	$ 2,658

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Total		Class A Common Stock	Treasury Stock		Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (shares) at Mar. 31, 2018				(158,028,673)	(14,582,134)
Beginning of period at Mar. 31, 2018		$ 562,491		$ 1,580	$ (461,457)		$ 346,958	$ 690,516	$ (15,106)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (shares)				417,366
Issuance of common stock		5,227		$ 5			5,222
Stock options exercised (shares)				678,173
Stock options exercised		8,541		$ 6			8,535
Repurchase of common stock (shares)				(1,900,000)	(1,991,299)
Repurchase of common stock		(89,231)		$ (85,400)	$ (89,231)
Net income		196,917						196,917
Other comprehensive income (loss), net of tax		3,789							3,789
Dividends paid per common share		(54,659)						(54,659)
Stock-based compensation expense		13,265					13,265
Ending balance (shares) at Sep. 30, 2018				(159,124,212)	(16,573,433)
End of period at Sep. 30, 2018		646,340		$ 1,591	$ (550,688)		373,980	832,774	(11,317)
Beginning balance (shares) at Jun. 30, 2018				(158,794,015)	(15,672,079)
Beginning of period at Jun. 30, 2018		607,481		$ 1,588	$ (509,521)		360,915	767,278	(12,779)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (shares)				97,091
Issuance of common stock		2,642		$ 1			2,641
Stock options exercised (shares)				233,106
Stock options exercised		3,276		$ 2			3,274
Repurchase of common stock (shares)					(901,354)
Repurchase of common stock		(41,167)			$ (41,167)
Net income		92,713						92,713
Other comprehensive income (loss), net of tax		1,462							1,462
Dividends paid per common share		(27,217)						(27,217)
Stock-based compensation expense		7,150					7,150
Ending balance (shares) at Sep. 30, 2018				(159,124,212)	(16,573,433)
End of period at Sep. 30, 2018		646,340		$ 1,591	$ (550,688)		373,980	832,774	(11,317)
Beginning balance (shares) at Mar. 31, 2019				(159,924,825)	(19,896,972)
Beginning of period at Mar. 31, 2019		675,366		$ 1,599	$ (711,450)		401,596	994,811	(11,190)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (shares)				246,233
Issuance of common stock		7,049		$ 3			7,046
Stock options exercised (shares)				229,299
Stock options exercised		3,687		$ 2			3,685
Repurchase of common stock (shares)				(93,000)	(129,935)	[1]
Repurchase of common stock		(8,343)	[1]	$ (5,900)	$ (8,343)	[1]
Recognition of liability related to future restricted stock units vesting		(318)					(318)
Net income		231,711						231,711
Other comprehensive income (loss), net of tax		(19,929)							(19,929)
Dividends paid per common share		(64,848)						(64,848)
Stock-based compensation expense		15,808					15,808
Ending balance (shares) at Sep. 30, 2019				(160,400,357)	(20,026,907)
End of period at Sep. 30, 2019		840,183		$ 1,604	$ (719,793)		427,817	1,161,674	(31,119)
Beginning balance (shares) at Jun. 30, 2019				(160,244,219)	(20,026,100)
Beginning of period at Jun. 30, 2019		748,823		$ 1,602	$ (719,736)		413,293	1,079,785	(26,121)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (shares)				88,141
Issuance of common stock		3,671		$ 1			3,670
Stock options exercised (shares)				67,997
Stock options exercised		1,532		$ 1			1,531
Repurchase of common stock (shares)	[1]				(807)
Repurchase of common stock	[1]	(57)			$ (57)
Recognition of liability related to future restricted stock units vesting		(41)					(41)
Net income		114,325						114,325
Other comprehensive income (loss), net of tax		(4,998)							(4,998)
Dividends paid per common share		(32,436)						(32,436)
Stock-based compensation expense		9,364					9,364
Ending balance (shares) at Sep. 30, 2019				(160,400,357)	(20,026,907)
End of period at Sep. 30, 2019		$ 840,183		$ 1,604	$ (719,793)		$ 427,817	$ 1,161,674	$ (31,119)
[1]	During the six months ended September 30, 2018 , the Company purchased 1.9 million shares of the Company’s Class A Common Stock in a series of open market transactions for $85.4 million . Additionally, the Company repurchased shares during the first quarter of fiscal 2019 to cover the minimum statutory withholding taxes on restricted stock units that vested on June 30, 2018.

Condensed Consolidated Statem_5

Condensed Consolidated Statements Of Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2019		Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018
Dividends paid (in dollars per share)	$ 0.23		$ 0.19	$ 0.46		$ 0.38
Repurchase of common stock, value	$ 57	[1]	$ 41,167	$ 8,343	[1]	$ 89,231
Class A Common Stock
Repurchase of common stock (in shares)				93		1,900
Repurchase of common stock, value				$ 5,900		$ 85,400
[1]	During the six months ended September 30, 2018 , the Company purchased 1.9 million shares of the Company’s Class A Common Stock in a series of open market transactions for $85.4 million . Additionally, the Company repurchased shares during the first quarter of fiscal 2019 to cover the minimum statutory withholding taxes on restricted stock units that vested on June 30, 2018.

Business Overview

Business Overview	6 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Overview	BUSINESS OVERVIEW Organization Booz Allen Hamilton Holding Corporation, including its wholly owned subsidiaries, or the Company, we, us, and our, was incorporated in Delaware in May 2008. The Company provides management and technology consulting, analytics, engineering, digital solutions, mission operations, and cyber expertise to U.S. and international governments, major corporations, and not-for-profit organizations. The Company reports operating results and financial data in one reportable segment. The Company is headquartered in McLean, Virginia, with approximately 27,000 employees as of September 30, 2019 .

Basis of Presentation

Basis of Presentation	6 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP, and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission, or SEC, and should be read in conjunction with the information contained in the Company's Annual Report on Form 10-K for the year ended March 31, 2019. The interim period unaudited condensed consolidated financial statements are presented as described below. Certain information and disclosures normally required for annual financial statements have been condensed or omitted pursuant to GAAP and SEC rules and regulations. In the opinion of management, all adjustments considered necessary for fair presentation of the results of the interim period presented have been included. The Company’s fiscal year ends on March 31 and unless otherwise noted, references to fiscal year or fiscal are for fiscal years ended March 31. The results of operations for the six months ended September 30, 2019 are not necessarily indicative of results to be expected for the full fiscal year. The condensed consolidated financial statements and notes of the Company include its subsidiaries, and the joint ventures and partnerships over which the Company has a controlling financial interest. The Company uses the equity method to account for investments in entities that it does not control if it is otherwise able to exert significant influence over the entities' operating and financial policies. Effective April 1, 2019, the Company adopted Accounting Standards Update (ASU) 2016-02, Leases (Topic 842), using the modified retrospective transition approach and, as a result, comparative information for the prior fiscal year has not been retrospectively adjusted. Certain amounts reported in the Company's prior year condensed consolidated financial statements have been reclassified to conform to the current year presentation. Accounting Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting periods. Areas of the financial statements where estimates may have the most significant effect include contractual and regulatory reserves, valuation and lives of tangible and intangible assets, contingent consideration related to business acquisitions, impairment of long-lived assets, accrued liabilities, revenue recognition, including the accrual of indirect costs, bonus and other incentive compensation, lease incremental borrowing rates, stock-based compensation, reserves for tax benefits and valuation allowances on deferred tax assets, provisions for income taxes, postretirement obligations, certain deferred costs, collectability of receivables, and loss accruals for litigation. Actual results experienced by the Company may differ materially from management's estimates. Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), to increase transparency and comparability of accounting for lease transactions. The new leasing standard requires lessees to recognize lease assets and lease liabilities on their balance sheet for all leases with a lease term greater than 12 months. Topic 842 is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB provided an alternative transition method of adoption through ASU 2018-11, Targeted Improvements, which permits the recognition of a cumulative-effect adjustment to retained earnings on the date of adoption. The Company adopted the standard on April 1, 2019 using the modified retrospective transition approach provided by ASU 2018-11, and, as a result, did not recast comparative prior period information. In addition, the Company elected certain practical expedients permitted under Topic 842, including the option not to apply lease recognition for short-term leases; an election to not separate lease from non-lease components; and a package of practical expedients such that, upon the initial adoption of Topic 842, the Company did not reassess whether expired or existing contracts contain leases, nor did the Company reassess the lease classification for expired or existing leases. The Company did not elect the practical expedient to use hindsight in determining the lease term and in assessing impairment of right-of-use (ROU) assets. Upon the adoption of Topic 842, the Company recognized ROU assets of $268.8 million and lease liabilities of $330.6 million on the condensed consolidated balance sheets, inclusive of required conforming balance sheet reclassifications pertaining to accounts such as deferred rent, tenant allowances, and lease receivables. As required under Topic 842 transition guidance, the lease liabilities recognized were measured at the present value of remaining minimum rental payments pursuant to Topic 840 which include executory costs. The impact to the condensed consolidated balance sheet at April 1 for the adoption of Topic 842 is as follows: Balance at March 31, 2019 Adoption adjustments for Topic 842 Balance at April 1, 2019 Current assets: Prepaid expenses and other current assets $ 84,986 $ (27,515 ) $ 57,471 Non-current assets: Operating lease right-of-use assets $ — $ 268,840 $ 268,840 Other long-term assets 91,837 (4,619 ) 87,218 Current liabilities: Accounts payable and other accrued expenses $ 664,948 $ (15,197 ) $ 649,751 Operating lease liabilities — 34,645 34,645 Non-current liabilities: Operating lease liabilities, net of current portion $ — $ 295,915 $ 295,915 Other long-term liabilities 275,399 (78,657 ) 196,742 Further, at the adoption of Topic 842, the Company recognized a deferred tax liability corresponding to the operating lease right-of-use assets of $69 million and a deferred tax asset corresponding to the operating lease liabilities of $93 million , inclusive of a decrease to deferred tax assets for the deferred rent and tenant allowances of $24 million as of March 31, 2019. There was no cumulative impact to retained earnings and the April 1, 2019 adoption of Topic 842 did not have a material impact to either of the condensed consolidated statements of operations or cash flows. In March 2019, the SEC issued Final Rule Release No. 33-10618, FAST Act Modernization and Simplification of Regulation S-K, amending certain disclosure requirements in Regulation S-K, with the intent of improving the readability of filed documents and simplifying registrants' compliance efforts. The Company adopted certain aspects of this final rule in the fourth quarter of fiscal 2019 which did not have a material impact on the condensed consolidated financial statements. Other aspects not yet adopted are still being evaluated but are not expected to be material. In August 2018, the SEC issued Final Rule Release No. 33-10532, Disclosure Update and Simplification , amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. This analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. The amendments became effective on November 5, 2018; however the SEC allows the filer’s first presentation of the changes in stockholders’ equity to be included in its Form 10-Q for the quarter that begins after the effective date of the amendments. Accordingly, the Company first presented the condensed consolidated statement of stockholders' equity in the Form 10-Q in the first quarter of fiscal 2020. The Company's adoption of this final rule did not have a material effect on the condensed consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In August 2018, the FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . This guidance requires a customer in a cloud computing arrangement that is a service contract to follow existing internal-use software guidance to determine which implementation costs to defer and recognize as an asset. ASU 2018-15 generally aligns the guidance on capitalizing implementation costs incurred in a cloud computing arrangement that is a service contract with that of implementation costs incurred to develop or obtain internal-use software, including hosting arrangements that include an internal-use software license. ASU 2018-15 is effective for interim reporting periods for fiscal years beginning after December 15, 2019. Early adoption is permitted. The standard may be adopted either retrospectively or prospectively. The Company is currently assessing the future impact of this update on its consolidated financial statements and related disclosures. Other accounting and reporting pronouncements effective after September 30, 2019 and issued through the filing date are not expected to have a material impact on the Company's condensed consolidated financial statements.

Revenue

Revenue	6 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE The Company's revenues from contracts with customers (clients) are derived from offerings that include consulting, analytics, digital solutions, engineering, and cyber services, substantially with the U.S. government and its agencies and, to a lesser extent, subcontractors. The Company also serves foreign governments, as well as domestic and international commercial clients. The Company performs under various types of contracts, which include cost-reimbursable-plus-fee contracts, time-and-materials contracts, and fixed-price contracts. Contract Estimates Many of our contracts recognize revenue under a contract cost-based input method and require an Estimate-at-Completion (EAC) process, which management uses to review and monitor the progress towards the completion of our performance obligations. Under this process, management considers various inputs and assumptions related to the EAC, including, but not limited to, progress towards completion, labor costs and productivity, material and subcontractor costs, and identified risks. Estimating the total cost at completion of performance obligations is subjective and requires management to make assumptions about future activity and cost drivers under the contract. Changes in these estimates can occur for a variety of reasons and, if significant, may impact the profitability of the Company’s contracts. Changes in estimates related to contracts accounted for under the EAC process are recognized on a cumulative catch-up basis in the period when such changes are determinable and reasonably estimable. If the estimate of contract profitability indicates an anticipated loss on a contract, the Company recognizes the total loss at the time it is identified. For each of the three and six months ended September 30, 2019 and 2018 , the aggregate impact of adjustments in contract estimates was not material. Disaggregation of Revenue We disaggregate our revenue from contracts with customers by contract type, customer, as well as whether the Company acts as prime contractor or sub-contractor, as we believe these categories best depict how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. The following series of tables presents our revenue disaggregated by these categories. Revenue by Contract Type: We generate revenue under the following three basic types of contracts: • Cost-Reimbursable Contracts: Cost-reimbursable contracts provide for the payment of allowable costs incurred during performance of the contract, up to a ceiling based on the amount that has been funded, plus a fixed fee or award fee. • Time-and-Materials Contracts: Under contracts in this category, we are paid a fixed hourly rate for each direct labor hour expended, and we are reimbursed for billable material costs and billable out-of-pocket expenses inclusive of allocable indirect costs. We assume the financial risk on time-and-materials contracts because our costs of performance may exceed negotiated hourly rates. • Fixed-Price Contracts: Under a fixed-price contract, we agree to perform the specified work for a predetermined price. To the extent our actual direct and allocated indirect costs decrease or increase from the estimates upon which the price was negotiated, we will generate more or less profit, respectively, or could incur a loss. The table below presents the total revenue for each type of contract: Three Months Ended Six Months Ended 2019 2018 2019 2018 Cost-reimbursable $ 1,026,055 57 % $ 851,394 53 % $ 2,052,648 56 % $ 1,711,278 53 % Time-and-materials 423,605 23 % 390,509 24 % 844,200 23 % 796,093 24 % Fixed-price 369,917 20 % 372,094 23 % 747,905 21 % 753,474 23 % Total Revenue $ 1,819,577 100 % $ 1,613,997 100 % $ 3,644,753 100 % $ 3,260,845 100 % Revenue by Customer Type: Three Months Ended Six Months Ended 2019 2018 2019 2018 U.S. government: Defense Clients $ 845,270 47 % $ 755,570 47 % $ 1,704,206 47 % $ 1,513,552 47 % Intelligence Clients 405,220 22 % 385,733 24 % 824,287 22 % 783,213 24 % Civil Clients 511,012 28 % 417,636 26 % 1,003,045 28 % 853,162 26 % Total U.S. government 1,761,502 97 % 1,558,939 97 % 3,531,538 97 % 3,149,927 97 % Global Commercial Clients 58,075 3 % 55,058 3 % 113,215 3 % 110,918 3 % Total Revenue $ 1,819,577 100 % $ 1,613,997 100 % $ 3,644,753 100 % $ 3,260,845 100 % Revenue by Whether the Company Acts as a Prime Contractor or a Sub-Contractor: Three Months Ended Six Months Ended 2019 2018 2019 2018 Prime Contractor $ 1,676,522 92 % $ 1,482,153 92 % $ 3,349,952 92 % $ 2,989,335 92 % Sub-contractor 143,055 8 % 131,844 8 % 294,801 8 % 271,510 8 % Total Revenue $ 1,819,577 100 % $ 1,613,997 100 % $ 3,644,753 100 % $ 3,260,845 100 % Performance Obligations Remaining performance obligations represent the transaction price of exercised contracts for which work has not yet been performed, irrespective of whether funding has or has not been authorized and appropriated as of the date of exercise. Remaining performance obligations do not include negotiated but unexercised options or the unfunded value of expired contracts. As of September 30, 2019 and March 31, 2019 , the Company had $7.6 billion and $5.8 billion , respectively, of remaining performance obligations and we expect to recognize more than half of the remaining performance obligations as revenue over the next 12 months, and approximately three quarters over the next 24 months. The remainder is expected to be recognized thereafter. Contract Balances The Company's performance obligations are typically satisfied over time and revenue is generally recognized using a cost-based input method. Fixed-price contracts are typically billed to the customer using milestone or fixed monthly payments, while cost-reimbursable-plus-fee and time-and-material contracts are typically billed to the customer at periodic intervals (e.g. monthly or weekly) as indicated by the terms of the contract. Disparities between the timing of revenue recognition and customer billings and cash collections results in net contract assets or liabilities being recognized at the end of each reporting period. Contract assets primarily consist of unbilled receivables typically resulting from revenue recognized exceeding the amount billed to the customer and right to payment is not just subject to the passage of time. Contract liabilities primarily consist of advance payments, billings in excess of costs incurred and deferred revenue. Contract assets and liabilities are reported on a net contract basis at the end of each reporting period. The Company maintains an allowance for doubtful accounts to provide for an estimate of uncollected receivables. Refer to Note 5 for more information on receivables recognized from contracts accounted for under Topic 606. The following table summarizes the contract balances recognized on the Company’s condensed consolidated balance sheets: September 30, March 31, Contract assets: Current $ 873,968 $ 846,372 Long-term 61,503 61,391 Total $ 935,471 $ 907,763 Contract liabilities: Advance payments, billings in excess of costs incurred and deferred revenue $ 22,822 $ 21,316 Changes in contract assets and contract liabilities are primarily due to the timing difference between the Company’s performance of services and payments from customers. For the three months ended September 30, 2019 and 2018 , we recognized revenue of $ 1.7 million and $ 2.1 million , respectively, and for the six months ended September 30, 2019 and 2018 , we recognized revenue of $18.4 million and $ 21.9 million related to our contract liabilities on April 1, 2019 and 2018, respectively. To determine revenue recognized from contract liabilities during the reporting periods, the Company allocates revenue to individual contract liability balances and applies revenue recognized during the reporting periods first to the beginning balances of contract liabilities until the revenue exceeds the balances.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The Company computes basic and diluted earnings per share amounts based on net income for the periods presented. The Company uses the weighted-average number of common shares outstanding during the period to calculate basic earnings per share, or EPS. Diluted EPS adjusts the weighted average number of shares outstanding to include the dilutive effect of outstanding common stock options and other stock-based awards. The Company currently has outstanding shares of Class A Common Stock. Unvested Class A Restricted Common Stock holders are entitled to participate in non-forfeitable dividends or other distributions. These unvested restricted shares participated in the Company's dividends declared and were paid in the first and second quarters of fiscal 2020 and 2019 . As such, EPS is calculated using the two-class method whereby earnings are reduced by distributed earnings as well as any available undistributed earnings allocable to holders of unvested restricted shares. A reconciliation of the income used to compute basic and diluted EPS for the periods presented are as follows: Three Months Ended Six Months Ended 2019 2018 2019 2018 Earnings for basic computations (1) $ 113,725 $ 92,127 $ 230,492 $ 195,681 Weighted-average common shares outstanding for basic computations 140,245,038 142,443,058 140,125,779 142,861,491 Earnings for diluted computations (1) $ 113,728 $ 92,130 $ 230,499 $ 195,690 Dilutive stock options and restricted stock 1,117,098 1,265,851 1,127,138 1,353,582 Weighted-average common shares outstanding for diluted computations 141,362,136 143,708,909 141,252,917 144,215,073 Earnings per common share Basic $ 0.81 $ 0.65 $ 1.64 $ 1.37 Diluted $ 0.80 $ 0.64 $ 1.63 $ 1.36 (1) During the three months ended September 30, 2019 and 2018 , approximately 0.7 million and 0.9 million participating securities, respectively, were paid dividends totaling $0.2 million in both periods. During the six months ended September 30, 2019 and 2018 , approximately 0.7 million and 0.9 million participating securities, respectively, were paid dividends totaling $0.3 million in both periods. For the three months ended September 30, 2019 and 2018 , there were undistributed earnings of $0.4 million allocated to the participating class of securities in both basic and diluted EPS in both periods. For the six months ended September 30, 2019 and 2018 , there were undistributed earnings of $0.9 million allocated to the participating class of securities in both basic and diluted EPS in both periods. The allocated undistributed earnings and the dividends paid comprise the difference between net income presented on the condensed consolidated statements of operations and earnings for basic and diluted computations for the three and six months ended September 30, 2019 and 2018 . The EPS calculation for the three and six months ended September 30, 2019 and 2018 excludes 0.2 million

Accounts Receivable, Net of All

Accounts Receivable, Net of Allowance	6 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Accounts Receivable, Net of Allowance	ACCOUNTS RECEIVABLE, NET OF ALLOWANCE Accounts receivable, net of allowance consisted of the following: September 30, March 31, Current assets Accounts receivable–billed $ 460,120 $ 494,671 Accounts receivable–unbilled 873,968 846,372 Allowance for doubtful accounts (12,977 ) (10,679 ) Accounts receivable, net of allowance 1,321,111 1,330,364 Other long-term assets Accounts receivable–unbilled 61,503 61,391 Total accounts receivable, net $ 1,382,614 $ 1,391,755 Unbilled amounts represent revenues for which billings have not been presented to customers at quarter-end or year-end. These amounts are generally billed and collected within one year subject to various conditions including, without limitation, appropriated and available funding. Long-term unbilled receivables not anticipated to be billed and collected within one year, which are primarily related to retainage, holdbacks, and long-term rate settlements to be billed at contract closeout, are included in other long-term assets in the accompanying condensed consolidated balance sheets. The Company recognized a provision for doubtful accounts (including certain unbilled reserves) of $0.5 million and $10.6 million for the three months ended September 30, 2019 and 2018 , respectively, and $ 1.3 million and $ 10.7 million for the six months ended September 30, 2019 and 2018 , respectively. The primary financial instruments, other than derivatives, that potentially subject the Company to concentrations of credit risk are accounts receivable. The Company's primary customers are U.S. federal government agencies and prime contractors under contracts with the U.S. government. The Company continuously reviews its accounts receivable and records provisions for doubtful accounts as needed.

Accounts Payable and Other Accr

Accounts Payable and Other Accrued Expenses	6 Months Ended
	Sep. 30, 2019
Payables and Accruals [Abstract]
Accounts Payable and Other Accrued Expenses	ACCOUNTS PAYABLE AND OTHER ACCRUED EXPENSES Accounts payable and other accrued expenses consisted of the following: September 30, March 31, Vendor payables $ 398,727 $ 417,648 Accrued expenses 285,647 247,300 Total accounts payable and other accrued expenses $ 684,374 $ 664,948 Accrued expenses consisted primarily of the Company’s reserve related to potential cost disallowance in conjunction with government audits. Refer to Note 18 for further discussion of this reserve.

Accrued Compensation and Benefi

Accrued Compensation and Benefits	6 Months Ended
	Sep. 30, 2019
Compensation Related Costs [Abstract]
Accrued Compensation and Benefits	ACCRUED COMPENSATION AND BENEFITS Accrued compensation and benefits consisted of the following: September 30, March 31, Bonus $ 52,199 $ 117,604 Retirement 68,902 37,678 Vacation 146,329 141,953 Other 23,321 28,318 Total accrued compensation and benefits $ 290,751 $ 325,553

Debt

Debt	6 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt	DEBT Debt consisted of the following: September 30, 2019 March 31, 2019 Interest Rate Outstanding Balance Interest Rate Outstanding Balance Term Loan A 3.54 % $ 1,400,726 4.00 % $ 1,037,713 Term Loan B 4.04 % 389,075 4.50 % 391,050 Senior Notes 5.13 % 350,000 5.13 % 350,000 Less: Unamortized debt issuance costs and discount on debt (17,056 ) (19,002 ) Total 2,122,745 1,759,761 Less: Current portion of long-term debt (77,924 ) (57,924 ) Long-term debt, net of current portion $ 2,044,821 $ 1,701,837 Term Loans and Revolving Credit Facility On July 23, 2018 (the "Amendment Effective Date"), Booz Allen Hamilton Inc. ("Booz Allen Hamilton") and Booz Allen Hamilton Investor Corporation ("Investor"), and certain wholly-owned subsidiaries of Booz Allen Hamilton, entered into the Sixth Amendment (the "Sixth Amendment") to the Credit Agreement (as amended, the "Credit Agreement"), dated as of July 31, 2012 among Booz Allen Hamilton, Investor, certain wholly-owned subsidiaries of Booz Allen Hamilton and Bank of America, N.A., as Administrative Agent and Collateral Agent and the other lenders and financial institutions from time to time party thereto (as previously amended by the First Amendment to the Credit Agreement, dated as of August 16, 2013, the Second Amendment to the Credit Agreement, dated as of May 7, 2014, the Third Amendment to the Credit Agreement, dated as of July 13, 2016, the Fourth Amendment to the Credit Agreement, dated as of February 6, 2017, and the Fifth Amendment to the Credit Agreement, dated as of March 7, 2018). The Sixth Amendment provided for a delayed draw (the "Delayed Draw Facility") on the tranche A term loan ("Term Loan A") facility in the amount of up to $400.0 million and extended the maturity of the Term Loan A and the revolving credit facility (the "Revolving Credit Facility") to July 2023. Additionally, the Sixth Amendment reduced the interest rate spread applicable to the Term Loan A and the Revolving Credit Facility from a range of 1.50% to 2.25% to a range of 1.25% to 2.00% based on consolidated net total leverage. The interest rate applicable to the Term Loan B ("Term Loan B" and, together with Term Loan A, the "Term Loans") remained unchanged. Prior to the Sixth Amendment, approximately $1,079.5 million was outstanding under Term Loan A. Pursuant to the Sixth Amendment, certain lenders converted their existing Term Loan A loans into a new tranche of Term Loan A loans in an aggregate amount, along with Term Loan A loans advanced by certain new lenders, of approximately $1,479.5 million , $400.0 million of which was available as the Delayed Draw Facility. On April 23, 2019, Booz Allen Hamilton drew down $400 million of the Delayed Draw Facility, the proceeds of which are expected to be used for general corporate purposes and other purposes not prohibited by the Credit Agreement. Prior to the Sixth Amendment, $500.0 million was available under the Revolving Credit Facility. Pursuant to the Sixth Amendment, certain lenders under the Credit Agreement converted their existing revolving commitments into a new tranche of revolving commitments (the "New Revolving Commitments" and the revolving credit loans made thereunder, the "New Revolving Loans") in an aggregate amount, along with New Revolving Commitments of certain new lenders, of $500.0 million . As of September 30, 2019 , the Credit Agreement provided Booz Allen Hamilton with a $1,400.7 million Term Loan A, a $389.1 million Term Loan B, and $500.0 million in New Revolving Commitments with a sub-limit for letters of credit of $100.0 million . As of September 30, 2019 , the maturity date of Term Loan A and the termination date for the Revolving Credit Facility was July 23, 2023 and the maturity date of Term Loan B was June 30, 2023. Booz Allen Hamilton’s obligations and the guarantors’ guarantees under the Credit Agreement are secured by a first priority lien on substantially all of the assets (including capital stock of subsidiaries) of Booz Allen Hamilton, Investor, and the subsidiary guarantors, subject to certain exceptions set forth in the Credit Agreement and related documentation. Subject to specified conditions, without the consent of the then-existing lenders (but subject to the receipt of commitments), the Term Loans or the Revolving Credit Facility may be expanded (or a new term loan facility or revolving credit facility added to the existing facilities) by up to (i) the greater of (x) $627 million and (y) 100% of consolidated EBITDA of Booz Allen Hamilton, as of the end of the most recently ended four quarter period for which financial statements have been delivered pursuant to the Credit Agreement plus (ii) the aggregate principal amount under which pro forma consolidated net secured leverage remains less than or equal to 3.50 : 1.00 . At Booz Allen Hamilton’s option, borrowings under the Secured Credit Facility bear interest based either on LIBOR (adjusted for maximum reserves, and subject to a floor of zero ) for the applicable interest period or a base rate (equal to the highest of (x) the administrative agent’s prime corporate rate, (y) the overnight federal funds rate plus 0.50% , and (z) three-month LIBOR (adjusted for maximum reserves, and subject to a floor of zero ) plus 1.00% ), in each case plus an applicable margin, payable at the end of the applicable interest period and in any event at least quarterly. The applicable margin for Term Loan A and borrowings under the Revolving Credit Facility ranges from 1.25% to 2.00% for LIBOR loans and 0.25% to 1.00% for base rate loans, in each case based on Booz Allen Hamilton’s consolidated total net leverage ratio. The applicable margin for Term Loan B is 2.00% for LIBOR loans and 1.00% for base rate loans. Unused commitments under the Revolving Credit Facility are subject to a quarterly fee ranging from 0.20% to 0.35% based on Booz Allen Hamilton’s consolidated total net leverage ratio. Booz Allen Hamilton occasionally borrows under the Revolving Credit Facility in anticipation of cash demands. During the first and second quarters of fiscal 2020 , Booz Allen Hamilton accessed no amounts of its $500.0 million Revolving Credit Facility. During the first and second quarters of fiscal 2019, Booz Allen Hamilton accessed a total of $70.0 million of its $500.0 million Revolving Credit Facility. As of September 30, 2019 and March 31, 2019 , there were no amounts outstanding under the Revolving Credit Facility. The Credit Agreement requires quarterly principal payments of 1.25% of the stated principal amount of Term Loan A until maturity, and quarterly principal payments of 0.25% of the stated principal amount of Term Loan B until maturity. The Credit Agreement contains customary representations and warranties and customary affirmative and negative covenants. The negative covenants include limitations on the following, in each case subject to certain exceptions: (i) indebtedness and liens; (ii) mergers, consolidations or amalgamations, liquidations, wind-ups or dissolutions, and disposition of all or substantially all assets; (iii) dispositions of property; (iv) restricted payments; (v) investments; (vi) transactions with affiliates; (vii) change in fiscal periods; (viii) negative pledges; (ix) restrictive agreements; (x) line of business; and (xi) speculative hedging. The events of default include the following, in each case subject to certain exceptions: (a) failure to make required payments under the Secured Credit Facility; (b) material breaches of representations or warranties under the Secured Credit Facility; (c) failure to observe covenants or agreements under the Secured Credit Facility; (d) failure to pay or default under certain other material indebtedness; (e) bankruptcy or insolvency; (f) certain Employee Retirement Income Security Act, or ERISA events; (g) certain material judgments; (h) actual or asserted invalidity of the Guarantee and Collateral Agreements or the other security documents or failure of the guarantees or perfected liens thereunder; and (i) a change of control. In addition, Booz Allen Hamilton is required to meet certain financial covenants at each quarter end, namely Consolidated Net Total Leverage and Consolidated Net Interest Coverage Ratios. As of September 30, 2019 and March 31, 2019 , Booz Allen Hamilton was in compliance with all financial covenants associated with its debt and debt-like instruments. For the three months ended September 30, 2019 and 2018 , interest payments of $13.9 million and $10.1 million were made for Term Loan A and $4.4 million and $4.0 million were made for Term Loan B, respectively. For the six months ended September 30, 2019 and 2018 , interest payments of $27.2 million and $21.1 million were made for Term Loan A and $8.8 million and $8.0 million were made for Term Loan B, respectively. Senior Notes On April 25, 2017, Booz Allen Hamilton issued $350 million aggregate principal amount of its 5.125% Senior Notes (the "Senior Notes") due 2025, under an Indenture, dated as of April 25, 2017, among Booz Allen Hamilton, certain subsidiaries of Booz Allen Hamilton, as guarantors (the "Subsidiary Guarantors"), and Wilmington Trust, National Association, as trustee (the "Trustee"), as supplemented by the First Supplemental Indenture, dated as of April 25, 2017, among Booz Allen Hamilton, the Subsidiary Guarantors and the Trustee. Each of Booz Allen Hamilton's existing and future domestic restricted subsidiaries that guarantee its obligations under the Secured Credit Facility and certain other indebtedness guarantee the Senior Notes on a senior unsecured basis. Interest is payable semi-annually on May 1 and November 1 of each year, beginning on November 1, 2017, and principal is due at maturity on May 1, 2025. In connection with the Senior Notes, the Company recognized $6.7 million of issuance costs, which were recorded as an offset against the carrying value of debt and will be amortized to interest expense over the term of the Senior Notes. Booz Allen Hamilton made interest payments of $9.0 million for the Senior Notes for each of the three and six months ended September 30, 2019 and 2018 . Borrowings under the Term Loans and, if used, the Revolving Credit Facility, incur interest at a variable rate. In accordance with Booz Allen Hamilton’s risk management strategy, between April 6, 2017 and April 4, 2019, Booz Allen Hamilton executed a series of interest rate swaps. As of September 30, 2019 , Booz Allen Hamilton had interest rate swaps with an aggregate notional amount of $1 billion . These instruments hedge the variability of cash outflows for interest payments on the floating portion of the Company's debt. The Company's objectives in using cash flow hedges are to reduce volatility due to interest rate movements and to add stability to interest expense (See Note 9 in our condensed consolidated financial statements). Interest on debt and debt-like instruments consisted of the following: Three Months Ended Six Months Ended 2019 2018 2019 2018 (In thousands) (In thousands) Term Loan A Interest Expense $ 13,584 $ 10,345 $ 27,034 $ 21,187 Term Loan B Interest Expense 4,232 4,115 8,652 8,032 Interest on Revolving Credit Facility — 2 — 61 Senior Notes Interest Expense 4,298 4,485 8,969 8,969 Deferred Payment Obligation Interest (1) 2,011 1,993 4,022 4,015 Amortization of Debt Issuance Cost (DIC) and Original Issue Discount (OID) (2) 1,425 1,258 2,459 2,618 Other 313 49 (86 ) 439 Total Interest Expense $ 25,863 $ 22,247 $ 51,050 $ 45,321 (1) Interest payments on the deferred payment obligation are made twice a year in January and July. (2) DIC and OID on the Term Loans and Senior Notes are recorded as a reduction of long-term debt in the condensed consolidated balance sheet and are amortized ratably over the life of the related debt using the effective rate method. DIC on the Revolving Credit Facility is recorded as a long-term asset on the condensed consolidated balance sheet and amortized ratably over the term of the Revolving Credit Facility.

Derivatives

Derivatives	6 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVES The Company utilizes derivative financial instruments to manage interest rate risk related to its variable rate debt. The Company’s objectives in using these interest rate derivatives, which were designated as cash flow hedges, are to manage its exposure to interest rate movements and reduce volatility of interest expense. During the first quarter of fiscal 2020, the Company entered into eight floating-to-fixed interest rate swap agreements with six financial institutions with a start date of April 30, 2019 with an aggregate notional amount of $400 million . The aggregate notional amount of all interest rate swap agreements increased to $1 billion as of September 30, 2019 . The swaps have staggered maturities, ranging from June 30, 2021 to June 30, 2025. The floating-to-fixed interest rate swaps involve the exchange of variable interest amounts from a counterparty for the Company making fixed-rate interest payments over the life of the agreements without exchange of the underlying notional amount and effectively converting a portion of the variable rate debt into fixed interest rate debt. Derivative instruments are recorded in the condensed consolidated balance sheet on a gross basis at estimated fair value. As of September 30, 2019 , $6.1 million and $23.8 million were classified as other current liabilities and other long-term liabilities, respectively, on the condensed consolidated balance sheet. As of March 31, 2019 , $1.8 million , $0.6 million , $0.9 million , and $4.3 million were classified as other current assets, other long-term assets, other current liabilities, and other long-term liabilities, respectively, on the condensed consolidated balance sheet. For interest rate swaps designated as cash flow hedges, the changes in the fair value of derivatives is recorded in Accumulated Other Comprehensive Income, or AOCI, net of taxes, and is subsequently reclassified into interest expense in the period that the hedged forecasted interest payments are made on the Company's variable-rate debt. The effect of derivative instruments on the accompanying condensed consolidated financial statements for the three and six months ended September 30, 2019 and 2018 is as follows: Three Months Ended September 30, Derivatives in Cash Flow Hedging Relationships Location of Gain or Loss Recognized in Income on Derivatives Amount of Gain or (Loss) Recognized in AOCI on Derivatives Amount of Gain or (Loss) Reclassified from AOCI into Income Interest Expense on Condensed Consolidated Statements of Operations 2019 2018 2019 2018 2019 2018 Interest rate swaps Interest expense $ (6,837 ) $ 1,522 $ 46 $ (116 ) $ (25,863 ) $ (22,247 ) Six Months Ended September 30, Derivatives in Cash Flow Hedging Relationships Location of Gain or Loss Recognized in Income on Derivatives Amount of Gain or (Loss) Recognized in AOCI on Derivatives Amount of Gain or (Loss) Reclassified from AOCI into Income Interest Expense on Condensed Consolidated Statements of Operations 2019 2018 2019 2018 2019 2018 Interest rate swaps Interest expense $ (26,585 ) $ 4,090 $ (477 ) $ (83 ) $ (51,050 ) $ (45,321 ) Over the next 12 months, the Company estimates that $6.2 million will be reclassified as an increase to interest expense. Cash flows associated with periodic settlements of interest rate swaps will be classified as operating activities in the condensed consolidated statement of cash flows. The Company is subject to counterparty risk in connection with its interest rate swap derivative contracts. Credit risk related to a derivative financial instrument represents the possibility that the counterparty will not fulfill the terms of the contract. The Company mitigates this credit risk by entering into agreements with credit-worthy counterparties and regularly reviews its credit exposure and the creditworthiness of the counterparties.

Leases

Leases	6 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	LEASES Under Topic 842, the Company determines whether the contract is, or contains, a lease, which exists when the contract conveys the right to control the use of identified property or equipment for a period of time in exchange for consideration. Operating leases are included in operating lease ROU assets, operating lease liabilities, and operating lease liabilities, net of current portion in our condensed consolidated balance sheets. Cash payments arising from operating leases are classified within operating activities in the condensed consolidated statement of cash flows. As of September 30, 2019 , the Company had no finance leases. The Company's leases are generally for facilities and office space and the Company recognizes operating lease ROU assets and operating lease liabilities at lease commencement date for those arrangements. The initial lease liability is equal to the present value of the future minimum lease payments over the lease term. The initial measurement of the right-of-use asset is equal to the initial lease liability plus any initial direct costs and prepaid lease payments, less any lease incentives. At the lease commencement date the Company estimates its collateralized incremental borrowing rate based on publicly available yields adjusted for Company-specific considerations and the Company's varying lease terms in determining the present value of future payments. Certain of the Company’s leases contain options to renew or to terminate the lease which are included in the determination of the ROU assets and lease liabilities when it is reasonably certain that the Company will exercise the option. The Company's leases may also include variable lease payments, such as maintenance costs, utilities, or other variable lease-related payments which are not included in measuring ROU assets and lease liabilities and are recorded as lease expense in the period incurred. As permitted under Topic 842, the Company elected not to recognize ROU assets and lease liabilities for leases with an initial term of 12 months or less; lease expense from these leases are recognized on a straight-line basis over the lease term. As further permitted under Topic 842, the Company elected to not separate lease components from non-lease components, accounting for both components as a single lease component. The Company’s total lease cost is recorded primarily within general and administrative expenses on the condensed consolidated statement of operations and consisted of the following: Three Months Ended September 30, 2019 Six Months Ended September 30, 2019 Operating lease cost $ 17,760 $ 35,720 Short-term lease cost 2,333 4,750 Variable lease cost 3,016 5,578 Total operating lease costs $ 23,109 $ 46,048 Future minimum operating lease payments for noncancelable operating leases as of September 30, 2019 are as follows: For the Fiscal Year Ending March 31, Operating Lease Payments Remainder of 2020 $ 19,899 2021 59,993 2022 60,883 2023 55,868 2024 48,057 Thereafter 130,040 Total future lease payments 374,740 Less: imputed interest (59,028 ) Total lease liabilities $ 315,712 Supplemental cash flow information related to leases was as follows: Six Months Ended September 30, 2019 Cash paid for amounts included in the measurement of lease liabilities $ 32,472 Operating lease liabilities arising from obtaining ROU assets (1) 9,681 (1) Includes all noncash increases and decreases arising from new or remeasured operating lease arrangements Other information related to leases was as follows: As of September 30, 2019 Weighted average remaining lease term (in years) 6.28 Weighted average discount rate 4.63 %

Income Taxes

Income Taxes	6 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The Company’s effective income tax rates were 22.8% and 22.7% for the three months ended September 30, 2019 and 2018 , respectively, and 23.8% and 23.5% for the six months ended September 30, 2019 and 2018 , respectively. The effective tax rates of 22.8% and 23.8% for the three and six months ended September 30, 2019 differ from the federal statutory rate of 21.0% primarily due to the inclusion of state and foreign income taxes and permanent rate differences, which are predominantly related to meals and entertainment and certain executive compensation, partially offset by discrete tax items. The Company is currently contesting tax assessments from the District of Columbia Office of Tax and Revenue for fiscal years 2013 through 2015 at various stages of applicable administrative and judicial processes, with a combined amount at issue of approximately $11.4 million , net of associated tax benefits as of September 30, 2019 . The Company has taken similar tax positions with respect to subsequent fiscal years, totaling in aggregate $33.5 million . As of September 30, 2019 , the Company does not maintain reserves for any uncertain tax positions related to the contested tax benefits or the similar tax positions taken in the subsequent fiscal years. Given the recoverable nature of the state tax expense, the Company does not believe that the resolution of these matters will have a material adverse effect on its results of operations, cash flows or financial condition. The Company maintained a reserve of $10.2 million as of September 30, 2019 relating to the acquisition of eGov Holdings, Inc. (d/b/a Aquilent) in the fourth quarter of fiscal 2017 for pre-acquisition period tax return uncertain tax positions.

Other Long-Term Liabilities

Other Long-Term Liabilities	6 Months Ended
	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Other Long-Term Liabilities	OTHER LONG-TERM LIABILITIES Other long-term liabilities consisted of the following: September 30, March 31, Deferred rent (1) $ — $ 78,658 Postretirement benefit obligations 127,877 124,925 Other (2) 62,690 71,816 Total other long-term liabilities $ 190,567 $ 275,399 (1) Deferred rent balance was reclassified to operating lease right-of-use assets on the condensed consolidated balance sheet as a result of the adoption of Topic 842. See Notes 2 and 10, respectively to our condensed consolidated financial statements. (2) Because of condensed financial statement presentation, components of other long-term liabilities at September 30, 2019 and March 31, 2019

Employee Benefit Plans

Employee Benefit Plans	6 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS Defined Contribution Plan The Company sponsors the Employees’ Capital Accumulation Plan, or ECAP, which is a qualified defined contribution plan that covers eligible U.S. and international employees. ECAP provides for distributions, subject to certain vesting provisions, to participants by reason of retirement, death, disability, or termination of employment. The Company has an annual matching contribution of up to 6% of eligible annual income as determined by the Internal Revenue Code for the ECAP. Total expense recognized under ECAP was $36.2 million and $33.6 million for the three months ended September 30, 2019 and 2018 , respectively, and $73.1 million and $66.2 million for the six months ended September 30, 2019 and 2018 , respectively. The Company-paid contributions were $22.1 million and $16.9 million for the three months ended September 30, 2019 and 2018 , respectively, and $42.0 million and $34.4 million for the six months ended September 30, 2019 and 2018 , respectively. Defined Benefit Plan and Other Postretirement Benefit Plans The Company provides postretirement healthcare benefits to former officers under a medical indemnity insurance plan, with premiums paid by the Company. This plan is referred to as the Officer Medical Plan. The Company also established a non-qualified defined benefit plan for all officers in May 1995, or the Retired Officers' Bonus Plan, which pays a lump-sum amount of $10,000 per year of service as an officer, provided the officer meets retirement vesting requirements. In addition, the Company provides a fixed annual allowance after retirement to cover financial counseling and other expenses. The Retired Officers' Bonus Plan is not salary related, but rather is based primarily on years of service. During fiscal 2017, the Company adopted a new plan which will provide for a one-time, lump sum retirement payment of one month’s salary when a vice-president retires from the Company, effective April 1, 2017. This is referred to as the Retired Vice-President Bonus Plan. Additionally, the Company offers medical and dental benefits to inactive employees (and their eligible dependents) on long-term disability. The components of net postretirement medical expense for the Officer Medical Plan were as follows: Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 1,239 $ 1,488 $ 2,478 $ 2,976 Interest cost 1,215 1,282 2,430 2,564 Net actuarial loss — 527 — 1,054 Total postretirement medical expense $ 2,454 $ 3,297 $ 4,908 $ 6,594 The service cost component of net periodic benefit cost is included in cost of revenue and general and administrative expenses, and the non-service cost components of net periodic benefit cost (interest cost and net actuarial loss) is included as part of other income (expense), net in the accompanying condensed consolidated statements of operations. As of September 30, 2019 and March 31, 2019 , the unfunded status of the post-retirement medical plan was $123.3 million and $120.3 million , respectively, which is included in other long-term liabilities in the accompanying condensed consolidated balance sheets. Long-term Disability Benefits The Company offers medical and dental benefits to inactive employees (and their eligible dependents) on long-term disability. These benefits do not vary with an employee's years of service; therefore, the Company is required to accrue the costs of the benefits at the date the inactive employee becomes disability eligible and elects to participate in the benefit. The accrued cost for such benefits is calculated using an actuarial estimate. The accrued cost for these benefits was $11.6 million at both September 30, 2019 and March 31, 2019 , and is presented in other long-term liabilities in the accompanying consolidated balance sheets. Deferred Compensation Plan The Company established a non-qualified deferred compensation plan (the "Plan") for certain executives and other highly compensated employees that was effective in fiscal 2018. Pursuant to the Plan, participants are eligible to defer up to 100% of their incentive cash compensation on a tax deferred basis in excess of the IRS limits imposed on 401(k) plans. The assets of the plan are held in a consolidated trust and are subject to the claims of the Company's general creditors under federal and state laws in the event of insolvency. Consequently, the trust qualifies as a Rabbi trust for income tax purposes. The fair values of plan investments and obligations at September 30, 2019 and March 31, 2019 were $6.7 million and $3.2 million , respectively, and were recorded in other long term assets and in other long term liabilities, respectively, in the condensed consolidated balance sheets. Adjustments to the fair value of the plan investments and obligations are recorded in operating expenses.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Loss	ACCUMULATED OTHER COMPREHENSIVE LOSS All amounts recorded in other comprehensive loss are related to the Company's post-retirement plans and interest rate swaps designated as cash flow hedges. The following table shows the changes in accumulated other comprehensive income (loss), net of tax: Three Months Ended September 30, 2019 Six Months Ended September 30, 2019 Post-retirement plans Derivatives designated as cash flow hedges Totals Post-retirement plans Derivatives designated as cash flow hedges Totals Beginning of period $ (9,034 ) $ (17,087 ) $ (26,121 ) $ (9,068 ) $ (2,122 ) $ (11,190 ) Other comprehensive loss before reclassifications (1) — (5,048 ) (5,048 ) — (19,627 ) (19,627 ) Amounts reclassified from accumulated other comprehensive loss 16 34 50 50 (352 ) (302 ) Net current-period other comprehensive income (loss) 16 (5,014 ) (4,998 ) 50 (19,979 ) (19,929 ) End of period $ (9,018 ) $ (22,101 ) $ (31,119 ) $ (9,018 ) $ (22,101 ) $ (31,119 ) (1) Changes in other comprehensive loss before reclassification for derivatives designated as cash flow hedges are recorded net of tax benefits of $1.8 million and $7.0 million for the three and six months ended September 30, 2019 , respectively. Three Months Ended September 30, 2018 Six Months Ended September 30, 2018 Post-retirement plans Derivatives designated as cash flow hedges Totals Post-retirement plans Derivatives designated as cash flow hedges Totals Beginning of period $ (20,548 ) $ 7,769 $ (12,779 ) $ (20,955 ) $ 5,849 $ (15,106 ) Other comprehensive income (loss) before reclassifications (2) — 1,123 1,123 — 3,019 3,019 Amounts reclassified from accumulated other comprehensive loss 424 (85 ) 339 831 (61 ) 770 Net current-period other comprehensive income (loss) 424 1,038 1,462 831 2,958 3,789 End of period $ (20,124 ) $ 8,807 $ (11,317 ) $ (20,124 ) $ 8,807 $ (11,317 ) (2) Changes in other comprehensive income (loss) before reclassification for derivatives designated as cash flow hedges are recorded net of tax expenses of $0.4 million and $1.1 million for the three and six months ended September 30, 2018 , respectively. The following table presents the reclassifications out of accumulated other comprehensive loss to net income: Three Months Ended Six Months Ended 2019 2018 2019 2018 Amounts reclassified from accumulated other comprehensive loss: Post-retirement plans (Note 13): Amortization of net actuarial loss included in net periodic benefit cost $ 22 $ 551 $ 66 $ 1,101 Tax benefit (expense) (6 ) (127 ) (16 ) (270 ) Net of tax $ 16 $ 424 $ 50 $ 831 Derivatives designated as cash flow hedges (Note 9): Reclassification of hedge (loss) gain $ 46 $ (116 ) $ (477 ) $ (83 ) Tax benefit (expense) (12 ) 31 125 22 Net of tax $ 34 $ (85 ) $ (352 ) $ (61 )

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The following table summarizes stock-based compensation expense recognized in the condensed consolidated statements of operations: Three Months Ended Six Months Ended 2019 2018 2019 2018 Cost of revenue $ 2,538 $ 2,534 $ 4,472 $ 3,978 General and administrative expenses 6,826 4,616 11,336 9,287 Total $ 9,364 $ 7,150 $ 15,808 $ 13,265 The following table summarizes the total stock-based compensation expense recognized in the condensed consolidated statements of operations by the following types of equity awards: Three Months Ended Six Months Ended 2019 2018 2019 2018 Equity Incentive Plan Options $ 722 $ 586 $ 1,207 $ 919 Class A Restricted Common Stock 8,642 6,564 14,601 12,346 Total $ 9,364 $ 7,150 $ 15,808 $ 13,265 As of September 30, 2019 , there was $47.7 million of total unrecognized compensation cost related to unvested stock-based compensation agreements. The unrecognized compensation cost as of September 30, 2019 is expected to be fully amortized over the next 4.50 years. Absent the effect of accelerating stock compensation cost for any departures of employees who may continue to vest in their equity awards, the following table summarizes the unrecognized compensation cost and the weighted-average period the cost is expected to be amortized. September 30, 2019 Unrecognized Compensation Cost Weighted Average Remaining Period to be Recognized (in years) Equity Incentive Plan Options $ 4,990 3.83 Class A Restricted Common Stock 42,711 2.02 Total $ 47,701 Equity Incentive Plan As of September 30, 2019 , there were 2,075,077 EIP options outstanding, of which 821,634 were unvested. Grants of Restricted Stock Units and Class A Restricted Common Stock During the three months ended September 30, 2019 , the Board of Directors granted 11,271 restricted stock units to certain employees of the Company and granted 30,389 shares of Class A Restricted Common Stock to members of the Board of Directors. The aggregate value of these awards was $2.9 million based on the grant date stock price, which ranged from $67.80 to $72.94 . Employee Stock Purchase Plan For the quarterly offering period that closed on September 30, 2019 , 54,408 Class A Common Stock shares were purchased by employees under the Company's Employee Stock Purchase Plan, or ESPP. Since the program's inception, 2,540,103 shares have been purchased by employees.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The accounting standard for fair value measurements establishes a three-tier value hierarchy, which prioritizes the inputs used in measuring fair value as follows: observable inputs such as quoted prices in active markets (Level 1); inputs other than quoted prices in active markets that are observable either directly or indirectly (Level 2); and unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions (Level 3). A financial instrument's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The financial instruments measured at fair value in the accompanying condensed consolidated balance sheets consist of the following: Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Assets: Long term deferred compensation costs (2) 6,725 — — 6,725 Total Assets $ 6,725 $ — $ — $ 6,725 Liabilities: Contingent consideration liability (3) $ — $ — $ 1,224 1,224 Current derivative instruments (1) — 6,101 — 6,101 Long term derivative instruments (1) — 23,834 — 23,834 Long term deferred compensation costs (2) 6,725 — — 6,725 Total Liabilities $ 6,725 $ 29,935 $ 1,224 $ 37,884 Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Assets: Current derivative instruments (1) $ — $ 1,790 $ — $ 1,790 Long term derivative instruments (1) — 614 — 614 Long term deferred compensation costs (2) 3,169 — — 3,169 Total Assets $ 3,169 $ 2,404 $ — $ 5,573 Liabilities: Contingent consideration liability (3) $ — $ — $ 1,224 $ 1,224 Current derivative instruments (1) — 929 — 929 Long term derivative instruments (1) — 4,347 — 4,347 Long term deferred compensation costs (2) 3,169 — — 3,169 Total Liabilities $ 3,169 $ 5,276 $ 1,224 $ 9,669 (1) The Company’s interest rate swaps are considered over-the-counter derivatives and fair value is estimated based on the present value of future cash flows using a model-derived valuation that uses Level 2 observable inputs such as interest rate yield curves. See Note 9 for further discussion on the Company’s derivative instruments designated as cash flow hedges. (2) Investments in this category consist primarily of mutual funds whose fair values are determined by reference to the quoted market price per unit in active markets multiplied by the number of units held without consideration of transaction costs. These assets represent investments held in a consolidated trust to fund the Company's non-qualified deferred compensation plan and are recorded in other long-term assets and other long-term liabilities on our condensed consolidated balance sheets. (3) The Company recognized a contingent consideration liability of $3.6 million in connection with its acquisition of Aquilent in fiscal 2017. As of both September 30, 2019 and March 31, 2019 , the estimated fair value of the contingent consideration liability was $1.2 million , and was valued using probability-weighted cash flows, which is based on the use of Level 3 fair value measurement inputs. The fair value of the Company's cash and cash equivalents, which are primarily Level 1 inputs, approximated its carrying values at September 30, 2019 and March 31, 2019 . The fair value of the Company's debt instruments approximated its carrying value at September 30, 2019 and March 31, 2019 . The fair value of debt is determined using quoted prices or other market information obtained from recent trading activity of each debt tranche in markets that are not active (Level 2 inputs). The fair value is corroborated by prices derived from the interest rate spreads of recently completed leveraged loan transactions of a similar credit profile, industry, and terms to that of the Company. The fair value of the Senior Notes is determined using quoted prices or other market information obtained from recent trading activity in the high-yield bond market (Level 2 inputs).

Related-Party Transactions

Related-Party Transactions	6 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related-Party Transactions	RELATED-PARTY TRANSACTIONS Two of our directors currently serve on the board of directors of a subcontractor to which the Company subcontracted $15.6 million and $39.8 million of services for the three and six months ended September 30, 2019 , respectively.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Letters of Credit and Third-Party Guarantees As of September 30, 2019 and March 31, 2019 , the Company was contingently liable under open standby letters of credit and bank guarantees issued by our banks in favor of third parties that totaled $9.2 million and $9.5 million , respectively. These letters of credit and bank guarantees primarily support insurance and bid and performance obligations. At September 30, 2019 and March 31, 2019 , approximately $0.9 million and $1.0 million , respectively, of these instruments reduced the available borrowings under the Revolving Credit Facility. The remainder is guaranteed under a separate $15.0 million facility established in fiscal 2015 of which $6.7 million and $6.5 million were available to the Company at September 30, 2019 and March 31, 2019 , respectively. Government Contracting Matters For the three months ended September 30, 2019 and 2018 , approximately 97% and 96% of the Company's revenue, respectively, was generated from contracts where the end user was an agency or department of the U.S. government, including contracts where the Company performed either as a prime contractor or subcontractor, and regardless of the geographic location in which the work was performed. For both the six months ended September 30, 2019 and 2018 , approximately 97% of the Company's revenue was generated from such contracts. U.S. government contracts and subcontracts are subject to extensive legal and regulatory requirements. From time to time and in the ordinary course of business, agencies of the U.S. government audit our contract costs and conduct inquiries and investigations of our business practices with respect to government contracts to determine whether the Company’s operations are conducted in accordance with these requirements and the terms of the relevant contracts. U.S. government agencies, including the Defense Contract Audit Agency, routinely audit our contract costs, including allocated indirect costs for compliance with the Cost Accounting Standards and the Federal Acquisition Regulation. These agencies also conduct reviews and investigations and make inquiries regarding our accounting and other systems in connection with our performance and business practices with respect to our government contracts and subcontracts. U.S. government audits, inquiries, or investigations of the Company, whether related to the Company's U.S. government contracts or subcontracts or conducted for other reasons, could result in administrative, civil, or criminal liabilities, including withholding of payments, suspension of payments, repayments, fines, or penalties being imposed upon the Company, or could lead to suspension or debarment from future U.S. government contracting. Management believes it has recorded the appropriate provision for any audit, inquiry, or investigation of which it is aware. Management believes it has recorded the appropriate provision for the estimated losses that may be experienced from any such reductions and/or penalties. As of September 30, 2019 and March 31, 2019 , the Company had recorded liabilities of approximately $207.9 million and $195.3 million , respectively, for its current best estimate of amounts to be refunded to customers for potential adjustments from audits or reviews of contract costs incurred subsequent to fiscal 2011, and for contracts not yet closed that are impacted by settlement of audits or reviews of contract costs incurred in prior fiscal years. Litigation Our performance under U.S. government contracts and compliance with the terms of those contracts and applicable laws and regulations are subject to continuous audit, review, and investigation by the U.S. government, which may include such investigative techniques as subpoenas or civil investigative demands. Given the nature of our business, these audits, reviews, and investigations may focus, among other areas, on various aspects of procurement integrity, labor time reporting, sensitive and/or classified information access and control, executive compensation, and post government employment restrictions. We are not always aware of our status in such matters, but we are currently aware of certain pending audits and investigations involving labor time reporting, procurement integrity, and classified information access. In addition, from time to time, we are also involved in legal proceedings and investigations arising in the ordinary course of business, including those relating to employment matters, relationships with clients and contractors, intellectual property disputes, and other business matters. These legal proceedings seek various remedies, including claims for monetary damages in varying amounts, none of which are considered material, or are unspecified as to amount. Although the outcome of any such matter is inherently uncertain and may be materially adverse, based on current information, we do not expect any of the currently ongoing audits, reviews, investigations, or litigation to have a material adverse effect on our financial condition and results of operations. As of September 30, 2019 and March 31, 2019 , there were no material amounts accrued in the condensed consolidated financial statements related to these proceedings. Six former officers and stockholders who had departed the Company prior to the acquisition of the Company by the Carlyle Group (the "Carlyle Acquisition") have filed a total of nine suits in various jurisdictions, with original filing dates ranging from July 3, 2008 through December 15, 2009, against us and certain of our current and former directors and officers. Three of these suits were amended on July 2, 2010 and then further amended into one consolidated complaint on September 7, 2010. Another two of the original nine suits were consolidated into one complaint on September 24, 2014. Each of the suits arises out of the Carlyle Acquisition and alleges that the former stockholders are entitled to certain payments that they would have received if they had held their stock at the time of the Carlyle Acquisition. Some of the suits also allege that the acquisition price paid to stockholders was insufficient. The various suits assert claims for breach of contract, tortious interference with contract, breach of fiduciary duty, civil Racketeer Influenced and Corrupt Organizations Act, or RICO, violations, violations of ERISA, and/or securities and common law fraud. Three of these suits have been dismissed with all appeals exhausted. The two suits that were consolidated into one action on September 24, 2014 were settled on April 16, 2015. One of the remaining suits has been dismissed by the United States District Court for the Southern District of California and such dismissal was upheld by the United States Court of Appeals for the Ninth Circuit. The plaintiff in this suit subsequently filed a Petition for Writ of Certiorari to the United States Supreme Court, which was denied by the United States Supreme Court on January 9, 2017. The other three remaining suits that were previously consolidated on September 7, 2010 have been dismissed by the United States District Court for the Southern District of New York and were on appeal before the United States Court of Appeals for the Second Circuit. On July 13, 2017, the United States Court of Appeals for the Second Circuit affirmed the ruling of the United States District Court for the Southern District of New York, except for one plaintiff’s securities fraud claim, which was remanded to the United States District Court for the Southern District of New York to give the plaintiff, Paul Kocourek, leave to file another amended complaint to attempt to plead a securities fraud claim. On April 6, 2018, the plaintiff filed an amended complaint in which Mr. Kocourek, individually, as Trustee of the Paul Kocourek Trust and on behalf of a putative class, alleges that the Company and certain former officers and directors violated Sections 10(b), 20(a) and 14(e) of the Securities Exchange Act of 1934, as amended, or the Exchange Act. On June 2, 2019, the United States District Court for the Southern District of New York granted defendants' motion to dismiss the amended complaint in its entirety. On July 11, 2019, the plaintiff filed a notice to appeal the ruling. On October 17, 2019, the plaintiff and the defendants reached an agreement to settle this matter. Pursuant to that agreement, the plaintiff is obligated to dismiss his appeal. On June 7, 2017, Booz Allen Hamilton was informed that the U.S. Department of Justice (DOJ) is conducting a civil and criminal investigation of the Company. In connection with the investigation, the DOJ has requested information from the Company relating to certain elements of the Company’s cost accounting and indirect cost charging practices with the U.S. government. Since learning of the investigation, the Company has engaged a law firm experienced in these matters to represent the Company in connection with this matter and respond to the government's requests. As is commonly the case with this type of matter, the Company has also been in contact with other regulatory agencies and bodies, including the Securities and Exchange Commission, which notified the Company that it is conducting an investigation that the Company believes relates to the matters that are also the subject of the DOJ's investigation. The Company may receive additional regulatory or governmental inquiries related to the matters that are the subject of the DOJ's investigation. In accordance with the Company's practice, the Company is cooperating with all relevant government parties. The total cost associated with these matters will depend on many factors, including the duration of these matters and any related findings. At this stage, the Company is not able to reasonably estimate the expected amount or range of cost or any loss associated with these matters. On June 19, 2017, a purported stockholder of the Company filed a putative class action lawsuit in the United States District Court for the Eastern District of Virginia styled Langley v. Booz Allen Hamilton Holding Corp., No. 17-cv-00696 naming the Company, its Chief Executive Officer and its Chief Financial Officer as defendants purportedly on behalf of all purchasers of the Company’s securities from May 19, 2016 through June 15, 2017. On September 5, 2017, the court named two lead plaintiffs, and on October 20, 2017, the lead plaintiffs filed a consolidated amended complaint. The complaint asserts claims under Sections 10(b) and 20(a) of the Exchange Act and Rule 10b-5 promulgated thereunder, alleging misrepresentations or omissions by the Company purporting to relate to matters that are the subject of the DOJ investigation described above. The plaintiffs seek to recover from the Company and the individual defendants an unspecified amount of damages. The Company believes the suit lacks merit and intends to defend against the lawsuit. Motions to dismiss were argued on January 12, 2018, and on February 8, 2018, the court dismissed the amended complaint in its entirety without prejudice. At this stage of the lawsuit, the Company is not able to reasonably estimate the expected amount or range of cost or any loss associated with the lawsuit. On November 13, 2017, a Verified Shareholder Derivative Complaint was filed in the United States District Court for the District of Delaware styled Celine Thum v. Rozanski et al., C.A. No. 17-cv-01638, naming the Company as a nominal defendant and numerous current and former officers and directors as defendants. The complaint asserts claims for breach of fiduciary duties, unjust enrichment, waste of corporate assets, abuse of control, gross mismanagement, and violations of Sections 14(a), 10(b) and 20(a) of the Exchange Act, purportedly relating to matters that are the subject of the DOJ investigation described above. The parties have stipulated to a stay of the proceedings pending the outcome of the securities litigation (described above), which the court so ordered on January 24, 2018. At a status conference on October 31, 2019, the court ordered the parties to meet and confer and submit a status report by November 29, 2019. At this stage of the lawsuit, the Company is not able to reasonably estimate the expected amount or range of cost or any loss associated with the lawsuit.

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounting Estimates	Accounting Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting periods. Areas of the financial statements where estimates may have the most significant effect include contractual and regulatory reserves, valuation and lives of tangible and intangible assets, contingent consideration related to business acquisitions, impairment of long-lived assets, accrued liabilities, revenue recognition, including the accrual of indirect costs, bonus and other incentive compensation, lease incremental borrowing rates, stock-based compensation, reserves for tax benefits and valuation allowances on deferred tax assets, provisions for income taxes, postretirement obligations, certain deferred costs, collectability of receivables, and loss accruals for litigation. Actual results experienced by the Company may differ materially from management's estimates.
Recently Adopted Accounting Standards and Recent Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), to increase transparency and comparability of accounting for lease transactions. The new leasing standard requires lessees to recognize lease assets and lease liabilities on their balance sheet for all leases with a lease term greater than 12 months. Topic 842 is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB provided an alternative transition method of adoption through ASU 2018-11, Targeted Improvements, which permits the recognition of a cumulative-effect adjustment to retained earnings on the date of adoption. The Company adopted the standard on April 1, 2019 using the modified retrospective transition approach provided by ASU 2018-11, and, as a result, did not recast comparative prior period information. In addition, the Company elected certain practical expedients permitted under Topic 842, including the option not to apply lease recognition for short-term leases; an election to not separate lease from non-lease components; and a package of practical expedients such that, upon the initial adoption of Topic 842, the Company did not reassess whether expired or existing contracts contain leases, nor did the Company reassess the lease classification for expired or existing leases. The Company did not elect the practical expedient to use hindsight in determining the lease term and in assessing impairment of right-of-use (ROU) assets. In March 2019, the SEC issued Final Rule Release No. 33-10618, FAST Act Modernization and Simplification of Regulation S-K, amending certain disclosure requirements in Regulation S-K, with the intent of improving the readability of filed documents and simplifying registrants' compliance efforts. The Company adopted certain aspects of this final rule in the fourth quarter of fiscal 2019 which did not have a material impact on the condensed consolidated financial statements. Other aspects not yet adopted are still being evaluated but are not expected to be material. In August 2018, the SEC issued Final Rule Release No. 33-10532, Disclosure Update and Simplification , amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. This analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. The amendments became effective on November 5, 2018; however the SEC allows the filer’s first presentation of the changes in stockholders’ equity to be included in its Form 10-Q for the quarter that begins after the effective date of the amendments. Accordingly, the Company first presented the condensed consolidated statement of stockholders' equity in the Form 10-Q in the first quarter of fiscal 2020. The Company's adoption of this final rule did not have a material effect on the condensed consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In August 2018, the FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . This guidance requires a customer in a cloud computing arrangement that is a service contract to follow existing internal-use software guidance to determine which implementation costs to defer and recognize as an asset. ASU 2018-15 generally aligns the guidance on capitalizing implementation costs incurred in a cloud computing arrangement that is a service contract with that of implementation costs incurred to develop or obtain internal-use software, including hosting arrangements that include an internal-use software license. ASU 2018-15 is effective for interim reporting periods for fiscal years beginning after December 15, 2019. Early adoption is permitted. The standard may be adopted either retrospectively or prospectively. The Company is currently assessing the future impact of this update on its consolidated financial statements and related disclosures. Other accounting and reporting pronouncements effective after September 30, 2019 and issued through the filing date are not expected to have a material impact on the Company's condensed consolidated financial statements.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	6 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The impact to the condensed consolidated balance sheet at April 1 for the adoption of Topic 842 is as follows: Balance at March 31, 2019 Adoption adjustments for Topic 842 Balance at April 1, 2019 Current assets: Prepaid expenses and other current assets $ 84,986 $ (27,515 ) $ 57,471 Non-current assets: Operating lease right-of-use assets $ — $ 268,840 $ 268,840 Other long-term assets 91,837 (4,619 ) 87,218 Current liabilities: Accounts payable and other accrued expenses $ 664,948 $ (15,197 ) $ 649,751 Operating lease liabilities — 34,645 34,645 Non-current liabilities: Operating lease liabilities, net of current portion $ — $ 295,915 $ 295,915 Other long-term liabilities 275,399 (78,657 ) 196,742

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The table below presents the total revenue for each type of contract: Three Months Ended Six Months Ended 2019 2018 2019 2018 Cost-reimbursable $ 1,026,055 57 % $ 851,394 53 % $ 2,052,648 56 % $ 1,711,278 53 % Time-and-materials 423,605 23 % 390,509 24 % 844,200 23 % 796,093 24 % Fixed-price 369,917 20 % 372,094 23 % 747,905 21 % 753,474 23 % Total Revenue $ 1,819,577 100 % $ 1,613,997 100 % $ 3,644,753 100 % $ 3,260,845 100 % Revenue by Customer Type: Three Months Ended Six Months Ended 2019 2018 2019 2018 U.S. government: Defense Clients $ 845,270 47 % $ 755,570 47 % $ 1,704,206 47 % $ 1,513,552 47 % Intelligence Clients 405,220 22 % 385,733 24 % 824,287 22 % 783,213 24 % Civil Clients 511,012 28 % 417,636 26 % 1,003,045 28 % 853,162 26 % Total U.S. government 1,761,502 97 % 1,558,939 97 % 3,531,538 97 % 3,149,927 97 % Global Commercial Clients 58,075 3 % 55,058 3 % 113,215 3 % 110,918 3 % Total Revenue $ 1,819,577 100 % $ 1,613,997 100 % $ 3,644,753 100 % $ 3,260,845 100 % Revenue by Whether the Company Acts as a Prime Contractor or a Sub-Contractor: Three Months Ended Six Months Ended 2019 2018 2019 2018 Prime Contractor $ 1,676,522 92 % $ 1,482,153 92 % $ 3,349,952 92 % $ 2,989,335 92 % Sub-contractor 143,055 8 % 131,844 8 % 294,801 8 % 271,510 8 % Total Revenue $ 1,819,577 100 % $ 1,613,997 100 % $ 3,644,753 100 % $ 3,260,845 100 %
Summary of Contract Balances	The following table summarizes the contract balances recognized on the Company’s condensed consolidated balance sheets: September 30, March 31, Contract assets: Current $ 873,968 $ 846,372 Long-term 61,503 61,391 Total $ 935,471 $ 907,763 Contract liabilities: Advance payments, billings in excess of costs incurred and deferred revenue $ 22,822 $ 21,316

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Reconciliation of the income used to compute basic and diluted EPS	A reconciliation of the income used to compute basic and diluted EPS for the periods presented are as follows: Three Months Ended Six Months Ended 2019 2018 2019 2018 Earnings for basic computations (1) $ 113,725 $ 92,127 $ 230,492 $ 195,681 Weighted-average common shares outstanding for basic computations 140,245,038 142,443,058 140,125,779 142,861,491 Earnings for diluted computations (1) $ 113,728 $ 92,130 $ 230,499 $ 195,690 Dilutive stock options and restricted stock 1,117,098 1,265,851 1,127,138 1,353,582 Weighted-average common shares outstanding for diluted computations 141,362,136 143,708,909 141,252,917 144,215,073 Earnings per common share Basic $ 0.81 $ 0.65 $ 1.64 $ 1.37 Diluted $ 0.80 $ 0.64 $ 1.63 $ 1.36 (1) During the three months ended September 30, 2019 and 2018 , approximately 0.7 million and 0.9 million participating securities, respectively, were paid dividends totaling $0.2 million in both periods. During the six months ended September 30, 2019 and 2018 , approximately 0.7 million and 0.9 million participating securities, respectively, were paid dividends totaling $0.3 million in both periods. For the three months ended September 30, 2019 and 2018 , there were undistributed earnings of $0.4 million allocated to the participating class of securities in both basic and diluted EPS in both periods. For the six months ended September 30, 2019 and 2018 , there were undistributed earnings of $0.9 million allocated to the participating class of securities in both basic and diluted EPS in both periods. The allocated undistributed earnings and the dividends paid comprise the difference between net income presented on the condensed consolidated statements of operations and earnings for basic and diluted computations for the three and six months ended September 30, 2019 and 2018 .

Accounts Receivable, Net of A_2

Accounts Receivable, Net of Allowance (Tables)	6 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Schedule of Accounts Receivable, Net of Allowance	Accounts receivable, net of allowance consisted of the following: September 30, March 31, Current assets Accounts receivable–billed $ 460,120 $ 494,671 Accounts receivable–unbilled 873,968 846,372 Allowance for doubtful accounts (12,977 ) (10,679 ) Accounts receivable, net of allowance 1,321,111 1,330,364 Other long-term assets Accounts receivable–unbilled 61,503 61,391 Total accounts receivable, net $ 1,382,614 $ 1,391,755

Accounts Payable and Other Ac_2

Accounts Payable and Other Accrued Expenses (Tables)	6 Months Ended
	Sep. 30, 2019
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Accounts payable and other accrued expenses consisted of the following: September 30, March 31, Vendor payables $ 398,727 $ 417,648 Accrued expenses 285,647 247,300 Total accounts payable and other accrued expenses $ 684,374 $ 664,948

Accrued Compensation and Bene_2

Accrued Compensation and Benefits (Tables)	6 Months Ended
	Sep. 30, 2019
Compensation Related Costs [Abstract]
Schedule of accrued compensation and benefits	Accrued compensation and benefits consisted of the following: September 30, March 31, Bonus $ 52,199 $ 117,604 Retirement 68,902 37,678 Vacation 146,329 141,953 Other 23,321 28,318 Total accrued compensation and benefits $ 290,751 $ 325,553

Debt (Tables)

Debt (Tables)	6 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Debt	Debt consisted of the following: September 30, 2019 March 31, 2019 Interest Rate Outstanding Balance Interest Rate Outstanding Balance Term Loan A 3.54 % $ 1,400,726 4.00 % $ 1,037,713 Term Loan B 4.04 % 389,075 4.50 % 391,050 Senior Notes 5.13 % 350,000 5.13 % 350,000 Less: Unamortized debt issuance costs and discount on debt (17,056 ) (19,002 ) Total 2,122,745 1,759,761 Less: Current portion of long-term debt (77,924 ) (57,924 ) Long-term debt, net of current portion $ 2,044,821 $ 1,701,837
Schedule of Interest Expense	Interest on debt and debt-like instruments consisted of the following: Three Months Ended Six Months Ended 2019 2018 2019 2018 (In thousands) (In thousands) Term Loan A Interest Expense $ 13,584 $ 10,345 $ 27,034 $ 21,187 Term Loan B Interest Expense 4,232 4,115 8,652 8,032 Interest on Revolving Credit Facility — 2 — 61 Senior Notes Interest Expense 4,298 4,485 8,969 8,969 Deferred Payment Obligation Interest (1) 2,011 1,993 4,022 4,015 Amortization of Debt Issuance Cost (DIC) and Original Issue Discount (OID) (2) 1,425 1,258 2,459 2,618 Other 313 49 (86 ) 439 Total Interest Expense $ 25,863 $ 22,247 $ 51,050 $ 45,321 (1) Interest payments on the deferred payment obligation are made twice a year in January and July. (2) DIC and OID on the Term Loans and Senior Notes are recorded as a reduction of long-term debt in the condensed consolidated balance sheet and are amortized ratably over the life of the related debt using the effective rate method. DIC on the Revolving Credit Facility is recorded as a long-term asset on the condensed consolidated balance sheet and amortized ratably over the term of the Revolving Credit Facility.

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The effect of derivative instruments on the accompanying condensed consolidated financial statements for the three and six months ended September 30, 2019 and 2018 is as follows: Three Months Ended September 30, Derivatives in Cash Flow Hedging Relationships Location of Gain or Loss Recognized in Income on Derivatives Amount of Gain or (Loss) Recognized in AOCI on Derivatives Amount of Gain or (Loss) Reclassified from AOCI into Income Interest Expense on Condensed Consolidated Statements of Operations 2019 2018 2019 2018 2019 2018 Interest rate swaps Interest expense $ (6,837 ) $ 1,522 $ 46 $ (116 ) $ (25,863 ) $ (22,247 ) Six Months Ended September 30, Derivatives in Cash Flow Hedging Relationships Location of Gain or Loss Recognized in Income on Derivatives Amount of Gain or (Loss) Recognized in AOCI on Derivatives Amount of Gain or (Loss) Reclassified from AOCI into Income Interest Expense on Condensed Consolidated Statements of Operations 2019 2018 2019 2018 2019 2018 Interest rate swaps Interest expense $ (26,585 ) $ 4,090 $ (477 ) $ (83 ) $ (51,050 ) $ (45,321 )

Leases (Tables)

Leases (Tables)	6 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedules of Lease Cost	The Company’s total lease cost is recorded primarily within general and administrative expenses on the condensed consolidated statement of operations and consisted of the following: Three Months Ended September 30, 2019 Six Months Ended September 30, 2019 Operating lease cost $ 17,760 $ 35,720 Short-term lease cost 2,333 4,750 Variable lease cost 3,016 5,578 Total operating lease costs $ 23,109 $ 46,048 Supplemental cash flow information related to leases was as follows: Six Months Ended September 30, 2019 Cash paid for amounts included in the measurement of lease liabilities $ 32,472 Operating lease liabilities arising from obtaining ROU assets (1) 9,681 (1) Includes all noncash increases and decreases arising from new or remeasured operating lease arrangements Other information related to leases was as follows: As of September 30, 2019 Weighted average remaining lease term (in years) 6.28 Weighted average discount rate 4.63 %
Schedule of Future Minimum Operating Lease Payments	Future minimum operating lease payments for noncancelable operating leases as of September 30, 2019 are as follows: For the Fiscal Year Ending March 31, Operating Lease Payments Remainder of 2020 $ 19,899 2021 59,993 2022 60,883 2023 55,868 2024 48,057 Thereafter 130,040 Total future lease payments 374,740 Less: imputed interest (59,028 ) Total lease liabilities $ 315,712

Other Long-Term Liabilities (Ta

Other Long-Term Liabilities (Tables)	6 Months Ended
	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Summary of Other Long-Term Liabilities	Other long-term liabilities consisted of the following: September 30, March 31, Deferred rent (1) $ — $ 78,658 Postretirement benefit obligations 127,877 124,925 Other (2) 62,690 71,816 Total other long-term liabilities $ 190,567 $ 275,399 (1) Deferred rent balance was reclassified to operating lease right-of-use assets on the condensed consolidated balance sheet as a result of the adoption of Topic 842. See Notes 2 and 10, respectively to our condensed consolidated financial statements. (2) Because of condensed financial statement presentation, components of other long-term liabilities at September 30, 2019 and March 31, 2019 primarily include the Company's long-term disability obligation, the long-term liability portion of the Company's derivative instruments, income tax reserves and deferred tax liabilities.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	6 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Components of net postretirement medical expense	The components of net postretirement medical expense for the Officer Medical Plan were as follows: Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 1,239 $ 1,488 $ 2,478 $ 2,976 Interest cost 1,215 1,282 2,430 2,564 Net actuarial loss — 527 — 1,054 Total postretirement medical expense $ 2,454 $ 3,297 $ 4,908 $ 6,594

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Schedule of accumulated other comprehensive loss	The following table shows the changes in accumulated other comprehensive income (loss), net of tax: Three Months Ended September 30, 2019 Six Months Ended September 30, 2019 Post-retirement plans Derivatives designated as cash flow hedges Totals Post-retirement plans Derivatives designated as cash flow hedges Totals Beginning of period $ (9,034 ) $ (17,087 ) $ (26,121 ) $ (9,068 ) $ (2,122 ) $ (11,190 ) Other comprehensive loss before reclassifications (1) — (5,048 ) (5,048 ) — (19,627 ) (19,627 ) Amounts reclassified from accumulated other comprehensive loss 16 34 50 50 (352 ) (302 ) Net current-period other comprehensive income (loss) 16 (5,014 ) (4,998 ) 50 (19,979 ) (19,929 ) End of period $ (9,018 ) $ (22,101 ) $ (31,119 ) $ (9,018 ) $ (22,101 ) $ (31,119 ) (1) Changes in other comprehensive loss before reclassification for derivatives designated as cash flow hedges are recorded net of tax benefits of $1.8 million and $7.0 million for the three and six months ended September 30, 2019 , respectively. Three Months Ended September 30, 2018 Six Months Ended September 30, 2018 Post-retirement plans Derivatives designated as cash flow hedges Totals Post-retirement plans Derivatives designated as cash flow hedges Totals Beginning of period $ (20,548 ) $ 7,769 $ (12,779 ) $ (20,955 ) $ 5,849 $ (15,106 ) Other comprehensive income (loss) before reclassifications (2) — 1,123 1,123 — 3,019 3,019 Amounts reclassified from accumulated other comprehensive loss 424 (85 ) 339 831 (61 ) 770 Net current-period other comprehensive income (loss) 424 1,038 1,462 831 2,958 3,789 End of period $ (20,124 ) $ 8,807 $ (11,317 ) $ (20,124 ) $ 8,807 $ (11,317 ) (2) Changes in other comprehensive income (loss) before reclassification for derivatives designated as cash flow hedges are recorded net of tax expenses of $0.4 million and $1.1 million for the three and six months ended September 30, 2018 , respectively.
Reclassification out of accumulated other comprehensive loss to net income	The following table presents the reclassifications out of accumulated other comprehensive loss to net income: Three Months Ended Six Months Ended 2019 2018 2019 2018 Amounts reclassified from accumulated other comprehensive loss: Post-retirement plans (Note 13): Amortization of net actuarial loss included in net periodic benefit cost $ 22 $ 551 $ 66 $ 1,101 Tax benefit (expense) (6 ) (127 ) (16 ) (270 ) Net of tax $ 16 $ 424 $ 50 $ 831 Derivatives designated as cash flow hedges (Note 9): Reclassification of hedge (loss) gain $ 46 $ (116 ) $ (477 ) $ (83 ) Tax benefit (expense) (12 ) 31 125 22 Net of tax $ 34 $ (85 ) $ (352 ) $ (61 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Summary of Stock-Based Compensation Expense Recognized in the Condensed Consolidated Statements of Operations	The following table summarizes stock-based compensation expense recognized in the condensed consolidated statements of operations: Three Months Ended Six Months Ended 2019 2018 2019 2018 Cost of revenue $ 2,538 $ 2,534 $ 4,472 $ 3,978 General and administrative expenses 6,826 4,616 11,336 9,287 Total $ 9,364 $ 7,150 $ 15,808 $ 13,265 The following table summarizes the total stock-based compensation expense recognized in the condensed consolidated statements of operations by the following types of equity awards: Three Months Ended Six Months Ended 2019 2018 2019 2018 Equity Incentive Plan Options $ 722 $ 586 $ 1,207 $ 919 Class A Restricted Common Stock 8,642 6,564 14,601 12,346 Total $ 9,364 $ 7,150 $ 15,808 $ 13,265
Schedule of Unrecognized Compensation Cost	Absent the effect of accelerating stock compensation cost for any departures of employees who may continue to vest in their equity awards, the following table summarizes the unrecognized compensation cost and the weighted-average period the cost is expected to be amortized. September 30, 2019 Unrecognized Compensation Cost Weighted Average Remaining Period to be Recognized (in years) Equity Incentive Plan Options $ 4,990 3.83 Class A Restricted Common Stock 42,711 2.02 Total $ 47,701

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Recurring Fair Value Measurements	The financial instruments measured at fair value in the accompanying condensed consolidated balance sheets consist of the following: Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Assets: Long term deferred compensation costs (2) 6,725 — — 6,725 Total Assets $ 6,725 $ — $ — $ 6,725 Liabilities: Contingent consideration liability (3) $ — $ — $ 1,224 1,224 Current derivative instruments (1) — 6,101 — 6,101 Long term derivative instruments (1) — 23,834 — 23,834 Long term deferred compensation costs (2) 6,725 — — 6,725 Total Liabilities $ 6,725 $ 29,935 $ 1,224 $ 37,884 Recurring Fair Value Measurements Level 1 Level 2 Level 3 Total Assets: Current derivative instruments (1) $ — $ 1,790 $ — $ 1,790 Long term derivative instruments (1) — 614 — 614 Long term deferred compensation costs (2) 3,169 — — 3,169 Total Assets $ 3,169 $ 2,404 $ — $ 5,573 Liabilities: Contingent consideration liability (3) $ — $ — $ 1,224 $ 1,224 Current derivative instruments (1) — 929 — 929 Long term derivative instruments (1) — 4,347 — 4,347 Long term deferred compensation costs (2) 3,169 — — 3,169 Total Liabilities $ 3,169 $ 5,276 $ 1,224 $ 9,669 (1) The Company’s interest rate swaps are considered over-the-counter derivatives and fair value is estimated based on the present value of future cash flows using a model-derived valuation that uses Level 2 observable inputs such as interest rate yield curves. See Note 9 for further discussion on the Company’s derivative instruments designated as cash flow hedges. (2) Investments in this category consist primarily of mutual funds whose fair values are determined by reference to the quoted market price per unit in active markets multiplied by the number of units held without consideration of transaction costs. These assets represent investments held in a consolidated trust to fund the Company's non-qualified deferred compensation plan and are recorded in other long-term assets and other long-term liabilities on our condensed consolidated balance sheets. (3) The Company recognized a contingent consideration liability of $3.6 million in connection with its acquisition of Aquilent in fiscal 2017. As of both September 30, 2019 and March 31, 2019 , the estimated fair value of the contingent consideration liability was $1.2 million , and was valued using probability-weighted cash flows, which is based on the use of Level 3 fair value measurement inputs.

Business Overview (Details)

Business Overview (Details) employee in Thousands	6 Months Ended
	Sep. 30, 2019employeesegment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments | segment	1
Number of employees | employee	27

Basis of Presentation - Narrati

Basis of Presentation - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 01, 2019	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating lease right-of-use assets	$ 250,810	$ 268,840	$ 0
Total lease liabilities	$ 315,712	330,600
Deferred tax liability corresponding to operating lease right-of-use assets		69,000
Deferred tax asset corresponding to operating lease liabilities		$ 93,000
Operating lease, deferred rent and tenant allowances			$ 24,000

Basis of Presentation - Schedul

Basis of Presentation - Schedule of Effect of Adoption of ASC 842 (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 01, 2019	Mar. 31, 2019
Current assets:
Prepaid expenses and other current assets	$ 60,746	$ 57,471	$ 84,986
Non-current assets:
Operating lease right-of-use assets	250,810	268,840	0
Other long-term assets	91,710	87,218	91,837
Current liabilities:
Accounts payable and other accrued expenses	684,374	649,751	664,948
Operating lease liabilities	32,994	34,645
Non-current liabilities:
Operating lease liabilities, net of current portion	282,718	295,915
Other long-term liabilities	$ 190,567	196,742	$ 275,399
Accounting Standards Update 2016-02
Current assets:
Prepaid expenses and other current assets		(27,515)
Non-current assets:
Operating lease right-of-use assets		268,840
Other long-term assets		(4,619)
Current liabilities:
Accounts payable and other accrued expenses		(15,197)
Operating lease liabilities		34,645
Non-current liabilities:
Operating lease liabilities, net of current portion		295,915
Other long-term liabilities		$ (78,657)

Revenue - Schedules of Disaggre

Revenue - Schedules of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 1,819,577	$ 1,613,997	$ 3,644,753	$ 3,260,845
Total revenue (as a percent)	100.00%	100.00%	100.00%	100.00%
Prime Contractor
Disaggregation of Revenue [Line Items]
Revenue	$ 1,676,522	$ 1,482,153	$ 3,349,952	$ 2,989,335
Total revenue (as a percent)	92.00%	92.00%	92.00%	92.00%
Sub-contractor
Disaggregation of Revenue [Line Items]
Revenue	$ 143,055	$ 131,844	$ 294,801	$ 271,510
Total revenue (as a percent)	8.00%	8.00%	8.00%	8.00%
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue	$ 1,761,502	$ 1,558,939	$ 3,531,538	$ 3,149,927
Total revenue (as a percent)	97.00%	97.00%	97.00%	97.00%
Defense Clients | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue	$ 845,270	$ 755,570	$ 1,704,206	$ 1,513,552
Total revenue (as a percent)	47.00%	47.00%	47.00%	47.00%
Intelligence Clients | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue	$ 405,220	$ 385,733	$ 824,287	$ 783,213
Total revenue (as a percent)	22.00%	24.00%	22.00%	24.00%
Civil Clients | UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue	$ 511,012	$ 417,636	$ 1,003,045	$ 853,162
Total revenue (as a percent)	28.00%	26.00%	28.00%	26.00%
Global Commercial Clients
Disaggregation of Revenue [Line Items]
Revenue	$ 58,075	$ 55,058	$ 113,215	$ 110,918
Total revenue (as a percent)	3.00%	3.00%	3.00%	3.00%
Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	$ 1,026,055	$ 851,394	$ 2,052,648	$ 1,711,278
Total revenue (as a percent)	57.00%	53.00%	56.00%	53.00%
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenue	$ 423,605	$ 390,509	$ 844,200	$ 796,093
Total revenue (as a percent)	23.00%	24.00%	23.00%	24.00%
Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	$ 369,917	$ 372,094	$ 747,905	$ 753,474
Total revenue (as a percent)	20.00%	23.00%	21.00%	23.00%

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue, amount of remaining performance obligation	$ 7,600		$ 7,600		$ 5,800
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with customer, liability, revenue recognized	$ 1.7	$ 2.1	$ 18.4	$ 21.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, expected timing, period one			12 months
Remaining performance obligation, expected timing, period two			24 months
Remaining performance obligation, percentage	75.00%		75.00%

Revenue - Schedule of Contract

Revenue - Schedule of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019
Contract assets:
Current	$ 873,968	$ 846,372
Long-term	61,503	61,391
Total	935,471	907,763
Contract liabilities:
Advance payments, billings in excess of costs incurred and deferred revenue	$ 22,822	$ 21,316

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Earnings for basic computations	$ 113,725	$ 92,127	$ 230,492	$ 195,681
Earnings for diluted computations	$ 113,728	$ 92,130	$ 230,499	$ 195,690
Dilutive stock options and restricted stock (in shares)	1,117,098	1,265,851	1,127,138	1,353,582
Earnings per common share
Basic (in dollars per share)	$ 0.81	$ 0.65	$ 1.64	$ 1.37
Diluted (in dollars per share)	$ 0.80	$ 0.64	$ 1.63	$ 1.36
Unvested shares, cash dividends paid			$ 64,848	$ 54,659
Restricted stock
Earnings per common share
Unvested shares participating in the payment of the Company's dividends declared (in shares)	700,000	900,000	700,000	900,000
Unvested shares, cash dividends paid	$ 200	$ 200	$ 300	$ 300
Undistributed earnings allocated to participating securities, basic	400	400	900	900
Undistributed earnings allocated to participating securities, diluted	$ 400	$ 400	$ 900	$ 900
Stock options
Earnings per common share
Antidilutive options excluded from the computation of EPS (in shares)	200,000	200,000	200,000	200,000
Class A Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted-average common shares outstanding for basic computations (in shares)	140,245,038	142,443,058	140,125,779	142,861,491
Weighted-average common shares outstanding for diluted computations (in shares)	141,362,136	143,708,909	141,252,917	144,215,073

Accounts Receivable, Net of A_3

Accounts Receivable, Net of Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Current assets
Accounts receivable–billed	$ 460,120		$ 460,120		$ 494,671
Accounts receivable–unbilled	873,968		873,968		846,372
Allowance for doubtful accounts	(12,977)		(12,977)		(10,679)
Accounts receivable, net of allowance	1,321,111		1,321,111		1,330,364
Other long-term assets
Accounts receivable–unbilled	61,503		61,503		61,391
Total accounts receivable, net	1,382,614		1,382,614		$ 1,391,755
Provision for doubtful accounts	$ 500	$ 10,600	$ 1,300	$ 10,700

Accounts Payable and Other Ac_3

Accounts Payable and Other Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 01, 2019	Mar. 31, 2019
Payables and Accruals [Abstract]
Vendor payables	$ 398,727		$ 417,648
Accrued expenses	285,647		247,300
Total accounts payable and other accrued expenses	$ 684,374	$ 649,751	$ 664,948

Accrued Compensation and Bene_3

Accrued Compensation and Benefits (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019
Compensation Related Costs [Abstract]
Bonus	$ 52,199	$ 117,604
Retirement	68,902	37,678
Vacation	146,329	141,953
Other	23,321	28,318
Total accrued compensation and benefits	$ 290,751	$ 325,553

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019	Jul. 23, 2018	Jul. 22, 2018
Long-term Debt, Current and Noncurrent [Abstract]
Less: Unamortized debt issuance costs and discount on debt	$ (17,056)	$ (19,002)
Total	2,122,745	1,759,761
Less: Current portion of long-term debt	(77,924)	(57,924)
Long-term debt, net of current portion	$ 2,044,821	$ 1,701,837
Secured Debt | Term Loan A
Long-term Debt, Current and Noncurrent [Abstract]
Interest rate	3.54%	4.00%
Long-term debt outstanding	$ 1,400,726	$ 1,037,713	$ 1,479,500	$ 1,079,500
Secured Debt | Term Loan B
Long-term Debt, Current and Noncurrent [Abstract]
Interest rate	4.04%	4.50%
Long-term debt outstanding	$ 389,075	$ 391,050
Senior Notes | Senior Notes
Long-term Debt, Current and Noncurrent [Abstract]
Interest rate	5.13%	5.13%
Long-term debt outstanding	$ 350,000	$ 350,000

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	Apr. 23, 2019	Jul. 23, 2018	Jul. 22, 2018	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019	Apr. 25, 2017
Debt Instrument [Line Items]
Long-term debt, maximum expanded loan facility								$ 627,000,000
Percentage of consolidated EBITDA required for expansion of loan								100.00%
Net secured leverage ratio								350.00%
Delayed Draw Facility
Debt Instrument [Line Items]
Revolving credit facility, maximum borrowing capacity		$ 400,000,000
Proceeds from lines of credit	$ 400,000,000
Term Loan A
Debt Instrument [Line Items]
Interest payments				$ 13,900,000		$ 10,100,000		$ 27,200,000	$ 21,100,000
Term Loan A | Minimum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate		1.25%	1.50%					1.25%
Term Loan A | Maximum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate		2.00%	2.25%					2.00%
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, maximum borrowing capacity		$ 500,000,000	$ 500,000,000	500,000,000				$ 500,000,000
Proceeds from lines of credit				0	$ 0	70,000,000	$ 70,000,000
Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								1.50%
Revolving Credit Facility | London Interbank Offered Rate (LIBOR) | Maximum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								2.00%
Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								0.25%
Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								1.00%
Term Loan B
Debt Instrument [Line Items]
Interest payments				4,400,000		4,000,000		$ 8,800,000	8,000,000
Term Loan B | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								2.00%
Term Loan B | Base Rate
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								1.00%
Secured Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								1.00%
Secured Debt | London Interbank Offered Rate (LIBOR) | Minimum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								0.00%
Secured Debt | Overnight Federal Funds Rate
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								0.50%
Secured Debt | Base Rate | Minimum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								0.00%
Secured Debt | Term Loan A
Debt Instrument [Line Items]
Long-term debt outstanding		$ 1,479,500,000	$ 1,079,500,000	$ 1,400,726,000				$ 1,400,726,000		$ 1,037,713,000
Quarterly periodic payment percentage, principal				1.25%				1.25%
Secured Debt | Term Loan A | Base Rate | Minimum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								0.25%
Secured Debt | Term Loan A | Base Rate | Maximum
Debt Instrument [Line Items]
Long-term debt, basis spread on variable rate								1.00%
Secured Debt | Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee percentage								0.20%
Secured Debt | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee percentage								0.35%
Secured Debt | Term Loan B
Debt Instrument [Line Items]
Long-term debt outstanding				$ 389,075,000				$ 389,075,000		391,050,000
Quarterly periodic payment percentage, principal				0.25%				0.25%
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, maximum borrowing capacity				$ 500,000,000				$ 500,000,000
Revolving credit facility, amount outstanding				0				0		0
Letter of Credit
Debt Instrument [Line Items]
Revolving credit facility, maximum borrowing capacity				100,000,000				100,000,000
Senior Notes | Senior Notes due 2025
Debt Instrument [Line Items]
Long-term debt outstanding				350,000,000				350,000,000		$ 350,000,000
Interest payments				$ 9,000,000		$ 9,000,000		$ 9,000,000	$ 9,000,000
Term loan, face amount											$ 350,000,000
Debt instrument, stated percentage											5.125%
Debt issuance costs											$ 6,700,000

Debt - Schedule of Interest Exp

Debt - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Deferred Payment Obligation Interest	$ 2,011		$ 1,993	$ 4,022	$ 4,015
Amortization of Debt Issuance Cost (DIC) and Original Issue Discount (OID)	1,425		1,258	2,459	2,618
Other	313		49	(86)	439
Total Interest Expense	25,863	$ 22,247	22,247	51,050	45,321
Secured Debt | Term Loan A
Debt Instrument [Line Items]
Interest expense on debt	13,584		10,345	27,034	21,187
Secured Debt | Term Loan B
Debt Instrument [Line Items]
Interest expense on debt	4,232		4,115	8,652	8,032
Revolving Credit Facility
Debt Instrument [Line Items]
Interest expense on debt	0		2	0	61
Senior Notes
Debt Instrument [Line Items]
Interest expense on debt	$ 4,298		$ 4,485	$ 8,969	$ 8,969

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) $ in Millions	3 Months Ended
	Sep. 30, 2019USD ($)agreementfinancial_institution	Mar. 31, 2019USD ($)
Other Current Assets
Derivative [Line Items]
Fair value of derivative assets		$ 1.8
Long-term assets
Derivative [Line Items]
Fair value of derivative assets		0.6
Other Current Liabilities
Derivative [Line Items]
Fair value of derivative liabilities	$ 6.1	0.9
Other Noncurrent Liabilities
Derivative [Line Items]
Fair value of derivative liabilities	$ 23.8	$ 4.3
Designated as Hedging Instrument | Cash Flow Hedging | Forward Starting Floating-To-Fixed Interest Rate Swap
Derivative [Line Items]
Number of interest rate swap agreements entered into during period | agreement	8
Number of financial institutions | financial_institution	6
Derivative, Notional Amount	$ 400
Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Derivative, Notional Amount	1,000
Estimate of amount to be reclassified over the next 12 months	$ 6.2

Derivatives - Schedule of Effec

Derivatives - Schedule of Effect of Derivatives on Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest Expense on Condensed Consolidated Statements of Operations	$ (25,863)	$ (22,247)	$ (22,247)	$ (51,050)	$ (45,321)
Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in AOCI on Derivatives	(6,837)	1,522		(26,585)	4,090
Amount of Gain or (Loss) Reclassified from AOCI into Income	46	(116)		(477)	(83)
Interest Expense on Condensed Consolidated Statements of Operations	$ (25,863)	$ (22,247)		$ (51,050)	$ (45,321)

Leases - Schedule of Lease Cost

Leases - Schedule of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 17,760	$ 35,720
Short-term lease cost	2,333	4,750
Variable lease cost	3,016	5,578
Total operating lease costs	$ 23,109	$ 46,048

Leases - Minimum Future Obligat

Leases - Minimum Future Obligations for Operating Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 01, 2019
Leases [Abstract]
Remainder of 2020	$ 19,899
2021	59,993
2022	60,883
2023	55,868
2024	48,057
Thereafter	130,040
Total future lease payments	374,740
Less: imputed interest	(59,028)
Total lease liabilities	$ 315,712	$ 330,600

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow and Other Information (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2019USD ($)
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 32,472
Operating lease liabilities arising from obtaining ROU assets (1)	$ 9,681
Weighted average remaining lease term (in years)	6 years 3 months 10 days
Weighted average discount rate (as a percent)	4.63%

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating Loss Carryforwards [Line Items]
Effective income tax rate	22.80%	22.70%	23.80%	23.50%
Federal statutory rate (as a percent)			21.00%
Income tax uncertainty	$ 10.2		$ 10.2
Tax Years 2013-2015
Operating Loss Carryforwards [Line Items]
Income tax assessments			11.4
Tax Years 2016-2019
Operating Loss Carryforwards [Line Items]
Income tax assessments			$ 33.5

Other Long-Term Liabilities (De

Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 01, 2019	Mar. 31, 2019
Other Liabilities Disclosure [Abstract]
Deferred rent	$ 0		$ 78,658
Postretirement benefit obligations	127,877		124,925
Other	62,690		71,816
Total other long-term liabilities	$ 190,567	$ 196,742	$ 275,399

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Retirement Benefits [Abstract]
Employer matching contribution, percent of match			6.00%
Employees’ capital accumulation plan, total expense recognized	$ 36,200,000	$ 33,600,000	$ 73,100,000	$ 66,200,000
Employees’ capital accumulation plan, company-paid contributions	22,100,000	16,900,000	42,000,000	34,400,000
Defined Benefit Plan Disclosure [Line Items]
Long-term disability obligation	11,600,000		$ 11,600,000		$ 11,600,000
Maximum eligible deferral of compensation, percentage			100.00%
Deferred compensation plan, assets	6,700,000		$ 6,700,000		3,200,000
Deferred compensation plan, liabilities	6,700,000		6,700,000		3,200,000
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation arrangement with individual, annual cash award granted per year of service, amount			10,000
Officer Medical Plan | Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,239,000	1,488,000	2,478,000	2,976,000
Interest cost	1,215,000	1,282,000	2,430,000	2,564,000
Net actuarial loss	0	527,000	0	1,054,000
Total postretirement medical expense	2,454,000	$ 3,297,000	4,908,000	$ 6,594,000
Defined benefit plan, unfunded status of plan	$ 123,300,000		$ 123,300,000		$ 120,300,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Schedule of Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	$ 748,823	$ 607,481	$ 675,366	$ 562,491
Other comprehensive income (loss) before reclassifications	(5,048)	1,123	(19,627)	3,019
Amounts reclassified from accumulated other comprehensive loss	50	339	(302)	770
Total other comprehensive income (loss), net of tax	(4,998)	1,462	(19,929)	3,789
End of period	840,183	646,340	840,183	646,340
Post-retirement plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(9,034)	(20,548)	(9,068)	(20,955)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive loss	16	424	50	831
Total other comprehensive income (loss), net of tax	16	424	50	831
End of period	(9,018)	(20,124)	(9,018)	(20,124)
Derivatives designated as cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(17,087)		(2,122)
Other comprehensive income (loss) before reclassifications	(5,048)		(19,627)
Amounts reclassified from accumulated other comprehensive loss	34		(352)
Total other comprehensive income (loss), net of tax	(5,014)		(19,979)
End of period	(22,101)		(22,101)
Other comprehensive income (loss) before reclassifications, tax	1,800		7,000
Derivatives designated as cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period		7,769		5,849
Other comprehensive income (loss) before reclassifications		1,123		3,019
Amounts reclassified from accumulated other comprehensive loss		(85)		(61)
Total other comprehensive income (loss), net of tax		1,038		2,958
End of period		8,807		8,807
Other comprehensive income (loss) before reclassifications, tax		400		1,100
Totals
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(26,121)	(12,779)	(11,190)	(15,106)
End of period	$ (31,119)	$ (11,317)	$ (31,119)	$ (11,317)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Reclassifications out of Accumulated Other Comprehensive Loss to Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ 148,177	$ 119,887	$ 304,007	$ 257,254
Tax benefit (expense)	(33,852)	(27,174)	(72,296)	(60,337)
Net income	114,325	92,713	231,711	196,917
Reclassification out of Accumulated Other Comprehensive Income | Post-retirement Plans
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	22	551	66	1,101
Tax benefit (expense)	(6)	(127)	(16)	(270)
Net income	16	424	50	831
Reclassification out of Accumulated Other Comprehensive Income | Derivatives designated as cash flow hedges
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	46	(116)	(477)	(83)
Tax benefit (expense)	(12)	31	125	22
Net income	$ 34	$ (85)	$ (352)	$ (61)

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 9,364	$ 7,150	$ 15,808	$ 13,265
Stock options | EIP
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	722	586	1,207	919
Restricted stock | Annual Incentive Plan | Class A Common Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	8,642	6,564	14,601	12,346
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,538	2,534	4,472	3,978
General and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,826	$ 4,616	$ 11,336	$ 9,287

Stock-Based Compensation - Unre

Stock-Based Compensation - Unrecognized Compensation (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2019USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested stock-based compensation agreements	$ 47,701
Unrecognized compensation cost, amortization period	4 years 6 months
EIP | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested stock-based compensation agreements	$ 4,990
Unrecognized compensation cost, amortization period	3 years 9 months 29 days
Annual Incentive Plan | Restricted stock | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to unvested stock-based compensation agreements	$ 42,711
Unrecognized compensation cost, amortization period	2 years 7 days

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Plans (Details) $ / shares in Units, $ in Millions	3 Months Ended	107 Months Ended
	Sep. 30, 2019USD ($)$ / sharesshares	Sep. 30, 2019$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, total fair value | $	$ 2.9
Stock options | EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	2,075,077	2,075,077
Stock options outstanding, unvested (in shares)	821,634	821,634
Restricted stock units (RSUs) | EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	11,271
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock purchased by employees (in shares)	54,408	2,540,103
Class A Common Stock | Restricted stock | EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	30,389
Minimum | EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price on grant date (in dollars per share) | $ / shares	$ 67.80	$ 67.80
Maximum | EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price on grant date (in dollars per share) | $ / shares	$ 72.94	$ 72.94

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019	Mar. 31, 2017
Assets, Fair Value Disclosure [Abstract]
Long term deferred compensation costs	$ 6,700	$ 3,200
Liabilities, Fair Value Disclosure [Abstract]
Long term deferred compensation costs	6,700	3,200
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Current derivative instruments		1,790
Long term derivative instruments		614
Long term deferred compensation costs	6,725	3,169
Total Assets	6,725	5,573
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration, liability	1,224	1,224
Current derivative instruments	6,101	929
Long term derivative instruments	23,834	4,347
Long term deferred compensation costs	6,725	3,169
Total Liabilities	37,884	9,669
Fair Value, Measurements, Recurring | Level 1
Assets, Fair Value Disclosure [Abstract]
Current derivative instruments		0
Long term derivative instruments		0
Long term deferred compensation costs	6,725	3,169
Total Assets	6,725	3,169
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration, liability	0	0
Current derivative instruments	0	0
Long term derivative instruments	0	0
Long term deferred compensation costs	6,725	3,169
Total Liabilities	6,725	3,169
Fair Value, Measurements, Recurring | Level 2
Assets, Fair Value Disclosure [Abstract]
Current derivative instruments		1,790
Long term derivative instruments		614
Long term deferred compensation costs	0	0
Total Assets	0	2,404
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration, liability	0	0
Current derivative instruments	6,101	929
Long term derivative instruments	23,834	4,347
Long term deferred compensation costs	0	0
Total Liabilities	29,935	5,276
Fair Value, Measurements, Recurring | Level 3
Assets, Fair Value Disclosure [Abstract]
Current derivative instruments		0
Long term derivative instruments		0
Long term deferred compensation costs	0	0
Total Assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration, liability	1,224	1,224
Current derivative instruments	0	0
Long term derivative instruments	0	0
Long term deferred compensation costs	0	0
Total Liabilities	1,224	1,224
Other noncurrent liabilities | Fair Value, Measurements, Recurring | Level 3
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration, liability	$ 1,200	$ 1,200	$ 3,600

Related-Party Transactions (Det

Related-Party Transactions (Details) - Affiliated Entity - Services Performed Under Subcontractor $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2019USD ($)director	Sep. 30, 2019USD ($)director
Related Party Transaction [Line Items]
Number of directors | director	2	2
Payments to related party | $	$ 15.6	$ 39.8

Commitments and Contingencies -

Commitments and Contingencies - Guarantees and Contracts (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019	Mar. 31, 2015
Contracts with U.S. government agencies or other U.S. government contractors
Concentration Risk [Line Items]
Concentration risk, percentage	97.00%	96.00%	97.00%	97.00%
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Liability for reductions and/or penalties from U.S Government audits	$ 207.9		$ 207.9		$ 195.3
Financial Standby Letter of Credit
Concentration Risk [Line Items]
Guarantor obligations, carrying value	9.2		9.2		9.5
Guarantor obligations, reduction to available borrowings			0.9		1
Guarantor obligations, facility						$ 15
Guarantor obligations, available amount	$ 6.7		$ 6.7		$ 6.5

Commitments and Contingencies_2

Commitments and Contingencies - Litigation (Details)	Sep. 05, 2017plaintiff	Jan. 09, 2017claim	Apr. 16, 2015claim	Sep. 30, 2019claim	Dec. 15, 2009claimplaintiff	Sep. 24, 2014claim	Sep. 23, 2014claim	Sep. 07, 2010claim	Jul. 02, 2010claim
Former stockholder litigation
Loss Contingencies [Line Items]
Loss contingencies, number of plaintiffs | plaintiff					6
Loss contingencies, new claims filed, number					9
Loss contingencies, claims amended, number						1		1	3
Loss contingencies, claims dismissed, number		1		3
Loss contingency, claims amended, number of claims consolidated						2	2
Loss contingencies, claims settled, number			1
Former stockholder litigation | United States District Court for Southern District of New York
Loss Contingencies [Line Items]
Loss contingencies, pending claims, number								3
United States District Court for the Eastern District of Virginia styled Langley v. Booz Allen Hamilton Holding Corp.
Loss Contingencies [Line Items]
Loss contingencies, number of plaintiffs | plaintiff	2