Operating Leases (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense		$ 300		$ 800
Related Party
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	$ 0	265	$ 0	813
Terminal Facilities
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	500	500	1,000	1,100
Terminal Facilities | Related Party
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	$ 392	$ 466	$ 806	$ 931