Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurement (Details)

v3.10.0.1
Fair Value Measurement (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations - USD ($)
$ in Millions
3 Months Ended 6 Months Ended 10 Months Ended
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2017
Jun. 30, 2017
Jun. 30, 2018
Jun. 28, 2017
South Texas Fabrication Yards              
Long Lived Assets Held-for-sale [Line Items]              
Insurance settlement             $ 15.4
Texas North Yard              
Long Lived Assets Held-for-sale [Line Items]              
Impairment of real estate   $ 5.1       $ 8.9  
Impairment of assets held for sale   $ 0.8          
Shipyard Division Assets              
Long Lived Assets Held-for-sale [Line Items]              
Impairment of assets held for sale $ 0.6   $ 0.6 $ 0.4 $ 0.4