XML 61 R46.htm IDEA: XBRL DOCUMENT v3.20.4
Contract Assets and Liabilities - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Contractors [Abstract]    
Allowance for contract retainage $ 0.4 $ 0.1
Revenues recognized during period $ 72.2 $ 39.2