Related Party (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ 2,700,000		$ 1,300,000
Receipts for tractor sales	3,198,000	0
Operating Leases, Rent Expense	2,300,000	0
Expenses from transactions with related party	12,543,000
Related Party
Related Party Transaction [Line Items]
Payments for tractor purchase	11,483,000
Receipts for tractor sales	(3,198,000)
Payments for parts and services	1,542,000
Operating Leases, Rent Expense	1,830,000
Administrative services receipts	(141,000)
Terminal Facilities
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	1,100,000
Terminal Facilities | Related Party
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	1,027,000
Expenses from transactions with related party	$ 1,000,000