Fair Value Measurements (Details) - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Losses	$ 3,252	$ 2,515	$ 5,623	$ 6,190
Revenue earning equipment, Trucks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Losses	1,515	1,572	2,743	3,454
Revenue earning equipment, Tractors [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Losses	1,081	662	1,908	2,294
Revenue earning equipment, Trailers [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Losses	656	281	972	442
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale at fair value	15,819	17,267	15,819	17,267
Fair Value, Inputs, 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 at fair value	6,805	10,713	6,805	10,713
Fair Value, Inputs, 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 at fair value	7,389	6,057	7,389	6,057
Fair Value, Inputs, 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 at fair value	$ 1,625	$ 497	$ 1,625	$ 497