Quarterly report pursuant to Section 13 or 15(d)

Revenue, Contract Assets and Liabilities and Other Contract Matters - Summary of Remaining Performance Obligation by Operating Segment (Parenthetical) (Details)

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Revenue, Contract Assets and Liabilities and Other Contract Matters - Summary of Remaining Performance Obligation by Operating Segment (Parenthetical) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Apr. 19, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Performance obligation sold $ 3.5 $ 17.0  
Shipyard      
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Performance obligation expected to be recognized as revenue 2.9    
Shipyard | Divested Shipyard Contracts      
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Performance obligation sold $ 309.5    
Subsequent Event | Shipyard | Divested Shipyard Contracts | Minimum      
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Performance obligation expected to be recognized as revenue     $ 5.0
Subsequent Event | Shipyard | Divested Shipyard Contracts | Maximum      
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Performance obligation expected to be recognized as revenue     $ 10.0