Acquisitions (Details Textual) (USD $)	3 Months Ended								12 Months Ended						12 Months Ended		12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Euroway Ltd. [Member]	Dec. 31, 2012 Euroway Ltd. [Member]	Aug. 01, 2012 Euroway Ltd. [Member] Vehicle	Dec. 31, 2012 Hill Hire [Member]	Jun. 08, 2011 Hill Hire [Member] Trailer Vehicle Person Lease	Dec. 31, 2013 2011 Other Acquisitions [Member]	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]
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
Fair value of debt assumed on acquisition									0	379,000	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
Finite-Lived Customer Relationships, Gross												3,000,000
Customer relationship intangibles																		12,000,000
Acquisitions									(1,858,000)	(5,113,000)	(361,921,000)	(2,000,000)					(1,000,000)	(3,000,000)	(107,000,000)	(1,000,000)	(4,000,000)
Revenue	1,617,729,000	1,634,540,000	1,603,999,000	1,563,017,000	1,583,536,000	1,573,295,000	1,563,860,000	1,536,276,000	6,419,285,000	6,256,967,000	6,050,534,000
Net earnings	$ 64,607,000	$ 71,067,000	$ 62,194,000	$ 39,924,000	$ 53,844,000	$ 75,091,000	$ 46,723,000	$ 34,321,000	$ 237,792,000	$ 209,979,000	$ 169,777,000