Acquisitions (Details Textual) (USD $)	3 Months Ended								12 Months Ended					12 Months Ended			12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Euroway Ltd. [Member]	Aug. 01, 2012 Euroway Ltd. [Member] Vehicle	Dec. 31, 2012 Hill Hire [Member]	Dec. 31, 2011 Hill Hire [Member]	Jun. 08, 2011 Hill Hire [Member] Trailer Vehicle Lease Person	Dec. 31, 2012 2011 Other Acquisitions [Member]	Dec. 31, 2011 2011 Other Acquisitions [Member]	Dec. 31, 2012 Other Acquisitions [Member]	Dec. 31, 2011 Other Acquisitions [Member]	Dec. 31, 2010 Other Acquisitions [Member]	Dec. 31, 2011 Total Logistic Control [Member]	Dec. 31, 2010 Total Logistic Control [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price Adjustment														$ 2,000,000
Acquisitions (Textual) [Abstract]
Purchase price of acquisitions													2,000,000			251,000,000		114,000,000					207,000,000
Fair value of debt assumed on acquisition									379,000	0	0	20,000,000
Number of full service lease vehicles													560			8,000
Number of rental vehicles																5,700
Number of contractual customers acquired																400
Business Acquisition Number Of Contract Maintenance Vehicles Acquired													800
Number of trailers included in fleet																9,700
Transaction costs related to the acquisition												1,000,000			2,000,000
Goodwill												6,000,000						28,000,000					131,911,000
Finite-Lived Customer Relationships, Gross												3,000,000
Customer relationship intangibles																		12,000,000
Acquisitions									(5,113,000)	(361,921,000)	(211,897,000)	(1,000,000)					(2,883,000)	(107,000,000)	(1,073,000)	(1,000,000)	(8,000,000)	(3,000,000)
Business Acquisition, Contingent Consideration, at Fair Value													478,000
Revenue	1,583,536,000	1,573,295,000	1,563,860,000	1,536,276,000	1,541,094,000	1,570,720,000	1,513,344,000	1,425,376,000	6,256,967,000	6,050,534,000	5,136,435,000
Net earnings	53,844,000	75,091,000	46,723,000	34,321,000	48,095,000	56,524,000	40,033,000	25,125,000	209,979,000	169,777,000	118,170,000
Reduction in purchase price due to contractual adjustments																						$ 1,000,000