Quarterly report pursuant to Section 13 or 15(d)

Assets Held for Sale - Narrative (Details)

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Assets Held for Sale - Narrative (Details)
 1 Months Ended 9 Months Ended
Sep. 30, 2017
USD ($)
a
Sep. 30, 2017
USD ($)
a
drydock
Long Lived Assets Held-for-sale [Line Items]    
Drydocks sold | drydock   2
Disposal Group, Held-for-sale, Not Discontinued Operations    
Long Lived Assets Held-for-sale [Line Items]    
Property, plant and equipment held for sale $ 107,010,000 $ 107,010,000
South Texas Fabrication Yards | Disposal Group, Held-for-sale, Not Discontinued Operations    
Long Lived Assets Held-for-sale [Line Items]    
Property, plant and equipment held for sale 104,507,000 $ 104,507,000
Clean-up and repair related costs due to Hurricane Harvey $ 265,000  
Insurance deductible, percent 3.00% 3.00%
Insurance initial payment   $ 3,000,000
South Texas Fabrication Yards | Disposal Group, Held-for-sale, Not Discontinued Operations | Accrued Liabilities    
Long Lived Assets Held-for-sale [Line Items]    
Accrual for future repairs $ 2,700,000 2,700,000
South Texas Fabrication Yards | Disposal Group, Held-for-sale, Not Discontinued Operations | Maximum    
Long Lived Assets Held-for-sale [Line Items]    
Insurance coverage 25,000,000 25,000,000
South Texas Fabrication Yards | Disposal Group, Held-for-sale, Not Discontinued Operations | Minimum    
Long Lived Assets Held-for-sale [Line Items]    
Insurance deductible, value 500,000 500,000
Prospect Shipyard    
Long Lived Assets Held-for-sale [Line Items]    
Loss on sale of assets   259,000
Prospect Shipyard | Disposal Group, Held-for-sale, Not Discontinued Operations    
Long Lived Assets Held-for-sale [Line Items]    
Property, plant and equipment held for sale $ 2,503,000 $ 2,503,000
Area of leased facility (in acres) | a 35 35
Impairment of assets held for sale   $ 389,000
Prospect Shipyard | Disposal Group, Disposed of by Sale, Not Discontinued Operations    
Long Lived Assets Held-for-sale [Line Items]    
Proceeds from sale of assets $ 2,000,000 $ 2,000,000