Fair Value Measurements (Details 1) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Losses	$ 18,000
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale		10,978	24,388
Total Losses		10,764	16,428
Level 3 [Member] | Revenue earning equipment, Trucks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale		6,135	13,326
Total Losses		6,274	9,926
Level 3 [Member] | Revenue earning equipment, Tractors [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale		4,054	10,339
Total Losses		3,450	4,824
Level 3 [Member] | Revenue earning equipment, Trailers [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale		789	723
Total Losses		$ 1,040	$ 1,678