Related Party (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]
Due to Related Parties, Current	$ 1,100,000	$ 1,100,000		$ 1,300,000
Receipts for tractor sales		3,335,000	0
Operating Leases, Rent Expense	2,200,000	6,800,000	0
Expenses from transactions with related party	3,028,000	18,645,000
Due from Related Parties, Current	300,000	300,000
Related Party
Related Party Transaction [Line Items]
Payments for tractor purchase	4,707,000	16,533,000
Receipts for tractor sales	(5,545,000)	(10,042,000)
Operating Leases, Rent Expense	1,784,000	5,430,000
Payments for parts and services	1,368,000	4,275,000
Receipts for trailer sales	(103,000)	(103,000)
Administrative services receipts	(141,000)	(423,000)
Terminal Facilities
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	1,000,000	3,200,000
Terminal Facilities | Related Party
Related Party Transaction [Line Items]
Operating Leases, Rent Expense	958,000	2,975,000
Expenses from transactions with related party	$ 1,000,000	$ 3,000,000