Revenue from Contracts with Customers (Tables)

6 Months Ended

Jun. 30, 2021

Revenue from Contract with Customer [Abstract]

Revenue by Contract Type [Table Text Block]

	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
Cost-reimbursable	$	443,950	$	432,876	$	863,725	$	851,531
Fixed-price	117,474		120,359		249,682		241,914
Time-and-materials	87,154		79,257		168,395		149,959
Revenue	$	648,578	$	632,492	$	1,281,802	$	1,243,404

Revenue by Customer [Table Text Block]

	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
U.S. Government	$	642,755	$	622,627	$	1,271,253	$	1,223,155
State agencies, international agencies and commercial entities	5,823		9,865		10,549		20,249
Revenue	$	648,578	$	632,492	$	1,281,802	$	1,243,404

Revenue by Contractor Type [Table Text Block]

	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
Prime contractor	$	602,306	$	577,377	$	1,191,380	$	1,132,545
Subcontractor	46,272		55,115		90,422		110,859
Revenue	$	648,578	$	632,492	$	1,281,802	$	1,243,404

Schedule Of Contract Receivables [Table Text Block]

The components of our receivables are as follows (in thousands):

	June 30, 2021		December 31, 2020
Billed receivables	$	364,760	$	312,991
Unbilled receivables	112,002		106,007
Allowance for doubtful accounts	(17,918)		(18,377)
Receivables—net	$	458,844	$	400,621

Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]

The following table discloses when we expect to recognize the remaining performance obligation as revenue (in billions):

For the remaining six months ending December 31, 2021		For the year ending
		December 31, 2022		December 31, 2023		Thereafter
$	1.1	$	0.7	$	0.2	$	0.4