Related Party (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ 200		$ 100
Operating Leases, Rent Expense	600	$ 1,100
Costs and Expenses, Related Party	1,443	(3,027)
Related Party [Member]
Related Party Transaction [Line Items]
Payments for tractor purchase	0	2,099
Receipts for tractor sales	0	(8,527)
Receipts for trailer sales	(108)	0
Operating Leases, Rent Expense	548	1,085
Payments for parts and services	537	1,360
Terminal Facilities
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	500	1,000
Terminal Facilities | Related Party [Member]
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	$ 466	$ 956