XML 55 R44.htm IDEA: XBRL DOCUMENT v3.21.2
Revenue - Narrative (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Revenue From Contract With Customer [Abstract]          
Negotiable cost reductions cares act $ 4,300,000 $ 6,900,000 $ 21,900,000 $ 25,200,000  
Performance obligation unsatisfied or partially satisfied 150,700,000   150,700,000    
Impairment charges 0 0 0 0  
Cost of contracts net of accumulated amortization 4,200,000   4,200,000   $ 4,800,000
Contract cost, accumulated impairment $ 0 $ 0 $ 0 $ 0