Revenue Earning Equipment (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue Earning Equipment [Line Items]
Cost	$ 12,148,290	$ 10,890,902
Accumulated Depreciation	3,963,555	3,689,016
Revenue earning equipment depreciation expense	1,060,000	979,000	$ 910,000
Assets held under capital leases
Revenue Earning Equipment [Line Items]
Cost	47,000	48,000
Accumulated Depreciation	22,000	22,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Revenue Earning Equipment [Line Items]
Loss to reflect changes in fair value	$ 17,956	$ 10,764	$ 16,000