Quarterly report pursuant to Section 13 or 15(d)

Noncontrolling Interests in Subsidiaries (Details)

v3.8.0.1
Noncontrolling Interests in Subsidiaries (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Noncontrolling Interests in Subsidiaries [Line Items]      
Noncontrolling interests in subsidiaries $ 134,463   $ 129,678
Net Income (Loss) 5,558 $ 10,656  
Net Income (Loss) Attributable to Noncontrolling Interest $ 4,917 6,573  
Ocean Services [Member] | Sea-Vista [Member]      
Noncontrolling Interests in Subsidiaries [Line Items]      
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners 49.00%    
Noncontrolling interests in subsidiaries $ 133,473   128,550
Assets, Net 272,400    
Net Income (Loss) 10,000 13,100  
Net Income (Loss) Attributable to Noncontrolling Interest 4,900 $ 6,400  
Inland Services [Member] | Other Inland River Services Noncontrolling Interests [Member]      
Noncontrolling Interests in Subsidiaries [Line Items]      
Noncontrolling interests in subsidiaries $ 840   977
Other Segments [Member] | Other Noncontrolling Interests [Member]      
Noncontrolling Interests in Subsidiaries [Line Items]      
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners 5.00%    
Noncontrolling interests in subsidiaries $ 150   $ 151
Minimum [Member] | Inland Services [Member] | Other Inland River Services Noncontrolling Interests [Member]      
Noncontrolling Interests in Subsidiaries [Line Items]      
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners 3.00%    
Maximum [Member] | Inland Services [Member] | Other Inland River Services Noncontrolling Interests [Member]      
Noncontrolling Interests in Subsidiaries [Line Items]      
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners 51.80%