Revenue Recognition - Schedule of Percentage of Sales by Contract and Customer (Details) - Sales Revenue, Net	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Customers | U.S. government
Concentration Risk [Line Items]
Percentage of net sales	96.00%	95.00%
Customers | Non U.S. government
Concentration Risk [Line Items]
Percentage of net sales	4.00%	5.00%
Fixed-price | Contract
Concentration Risk [Line Items]
Percentage of net sales	61.00%	62.00%
Cost-reimbursable | Contract
Concentration Risk [Line Items]
Percentage of net sales	39.00%	37.00%
Other | Contract
Concentration Risk [Line Items]
Percentage of net sales	0.00%	1.00%
Real Estate | Segment Concentration Risk
Concentration Risk [Line Items]
Percentage of net sales	1.00%	1.00%