Revenue Recognition (Tables)

6 Months Ended

Jun. 30, 2022

Revenue From Contract With Customer [Abstract]

Disaggregation of Revenue

Disaggregation of Revenue

	Three Months Ended June 30,										Six Months Ended June 30,
	2022					2021					2022					2021
	Dollars		Percent			Dollars		Percent			Dollars		Percent			Dollars		Percent
Client Markets:
Energy, environment, and infrastructure	$	160,401		38	%	$	167,309		43	%	$	316,444		38	%	$	330,533		43	%
Health, education, and social programs		208,953		49	%		167,640		43	%		414,750		50	%		325,906		42	%
Safety and security		33,409		8	%		29,618		7	%		62,809		7	%		60,816		8	%
Consumer and financial		20,347		5	%		27,958		7	%		42,575		5	%		53,748		7	%
Total	$	423,110		100	%	$	392,525		100	%	$	836,578		100	%	$	771,003		100	%

	Three Months Ended June 30,										Six Months Ended June 30,
	2022					2021					2022					2021
	Dollars		Percent			Dollars		Percent			Dollars		Percent			Dollars		Percent
Client Type:
U.S. federal government	$	225,229		53	%	$	182,241		46	%	$	444,221		53	%	$	358,225		46	%
U.S. state and local government		64,056		15	%		58,487		15	%		130,165		16	%		115,637		15	%
International government		27,144		7	%		37,148		10	%		53,863		6	%		73,894		10	%
Total Government		316,429		75	%		277,876		71	%		628,249		75	%		547,756		71	%
Commercial		106,681		25	%		114,649		29	%		208,329		25	%		223,247		29	%
Total	$	423,110		100	%	$	392,525		100	%	$	836,578		100	%	$	771,003		100	%

	Three Months Ended June 30,										Six Months Ended June 30,
	2022					2021					2022					2021
	Dollars		Percent			Dollars		Percent			Dollars		Percent			Dollars		Percent
Contract Mix:
Time-and-materials	$	169,980		40	%	$	162,249		41	%	$	334,821		40	%	$	322,085		42	%
Fixed price		185,823		44	%		160,288		41	%		369,962		44	%		307,757		40	%
Cost-based		67,307		16	%		69,988		18	%		131,795		16	%		141,161		18	%
Total	$	423,110		100	%	$	392,525		100	%	$	836,578		100	%	$	771,003		100	%

Schedule of Contract Balances and Changes in Contract Balances

Contract Balances:

Contract assets consist primarily of unbilled amounts resulting from long-term contracts when revenue recognized exceeds the amount billed often due to billing schedule timing. Contract liabilities result from advance payments received on a contract or from billings in excess of revenue recognized on long-term contracts due to billing schedule timing.

The following table summarizes the contract balances as of June 30, 2022 and December 31, 2021:

	June 30, 2022			December 31, 2021			$ Change		% Change
Contract assets	$	190,506		$	137,867		$	52,639		38.2	%
Contract liabilities		(24,612	)		(39,665	)		15,053		(38.0	%)
Net contract assets (liabilities)	$	165,894		$	98,202		$	67,692		68.9	%