Annual report pursuant to Section 13 and 15(d)

Supplemental Information For Statements Of Cash Flows (Details)

v3.8.0.1
Supplemental Information For Statements Of Cash Flows (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Property, Plant and Equipment [Line Items]      
Income taxes paid $ 6,152 $ 11,933 $ 23,791
Income taxes refunded 14,347 3,933 4,550
Interest paid, excluding capitalized interest 32,341 26,662 23,957
Company financed sale of equipment and real property 0 7,950 1,768
Reclassification of Dorian to Marketable Securities 0 0 102,509
Distribution of Dorian shares to shareholders 31,379 0 0
Services and Equipment received to settle notes receivable 5,954 0 0
Noncash or Part Noncash Divestiture, Amount of Consideration Received   2,000  
Property, Plant and Equipment [Member]      
Property, Plant and Equipment [Line Items]      
Services and Equipment received to settle notes receivable 0 2,500 0
U.S.-flag Harbor Tugs [Member]      
Property, Plant and Equipment [Line Items]      
Noncash or Part Noncash Divestiture, Amount of Consideration Received $ 0 $ 2,000 $ 0