Annual report pursuant to Section 13 and 15(d)

Quarterly Operating Results (Unaudited) - Summary of Quarterly Results of Operations (Parenthetical) (Details)

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Quarterly Operating Results (Unaudited) - Summary of Quarterly Results of Operations (Parenthetical) (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Quarterly Financial Information Disclosure [Line Items]          
Impairments and (gain) loss on assets held for sale     $ 4,130 $ 17,528 $ (6,850)
Corporate          
Quarterly Financial Information Disclosure [Line Items]          
Impairment charges related to inventory and assets   $ 700      
Shipyard          
Quarterly Financial Information Disclosure [Line Items]          
Increase in operating income (loss) due to project charges $ 8,800 10,200 16,600 12,300 6,700
Impairments and (gain) loss on assets held for sale 1,600   1,639 7,920 964
Impairment charges related to inventory and assets   7,600      
F&S          
Quarterly Financial Information Disclosure [Line Items]          
Increase in operating income (loss) due to project charges   3,800 $ 2,700 $ 4,900 $ 2,400
Impairments and (gain) loss on assets held for sale $ 2,400        
Impairment charges related to inventory and assets   $ 9,000