XML 103 R66.htm IDEA: XBRL DOCUMENT v3.8.0.1
Other long-term liabilities - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2017
USD ($)
vessel
Dec. 31, 2016
USD ($)
Subclassifications of assets, liabilities and equities [abstract]    
Undiscounted amount of estimated cash flows required to settle liabilities $ 44.9 $ 41.1
Number of vessels delivered | vessel 2  
Total finance lease payments $ 30.6  
Interest expense on finance leases $ 23.7