Quarterly report pursuant to Section 13 or 15(d)

Assets Held for Sale - Significant Assets Included in Assets Held for Sale (Details)

v3.8.0.1
Assets Held for Sale - Significant Assets Included in Assets Held for Sale (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations - USD ($)
$ in Thousands
Apr. 20, 2018
Mar. 31, 2018
Long Lived Assets Held-for-sale [Line Items]    
Less: accumulated depreciation   $ (96,660)
Total assets held for sale   98,386
Texas South Yard    
Long Lived Assets Held-for-sale [Line Items]    
Less: accumulated depreciation   (43,808)
Total assets held for sale   49,897
Texas North Yard    
Long Lived Assets Held-for-sale [Line Items]    
Less: accumulated depreciation   (52,554)
Total assets held for sale   46,600
Shipyard Division Assets    
Long Lived Assets Held-for-sale [Line Items]    
Less: accumulated depreciation   (298)
Total assets held for sale   1,889
South Texas Fabrication Yards | Subsequent Event    
Long Lived Assets Held-for-sale [Line Items]    
Proceeds from sale of productive assets, net $ 53,500  
Land    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   5,492
Land | Texas South Yard    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   3,335
Land | Texas North Yard    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   2,157
Land | Shipyard Division Assets    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   0
Buildings and improvements    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   121,062
Buildings and improvements | Texas South Yard    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   90,370
Buildings and improvements | Texas North Yard    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   30,692
Buildings and improvements | Shipyard Division Assets    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   0
Machinery and equipment    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   68,492
Machinery and equipment | Texas South Yard    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   0
Machinery and equipment | Texas North Yard    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   66,305
Machinery and equipment | Shipyard Division Assets    
Long Lived Assets Held-for-sale [Line Items]    
Total assets held for sale, gross   $ 2,187