Acquisitions (Details Textuals) (USD $)	3 Months Ended				3 Months Ended			3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Hill Hire [Member]	Jun. 08, 2011 Hill Hire [Member] Trailer Vehicle Lease Customers	Mar. 31, 2012 Other Acquisitions [Member]	Mar. 31, 2011 Other Acquisitions [Member]	Dec. 31, 2011 Other Acquisitions [Member]	Mar. 31, 2012 Other Acquisitions Completed in Prior Years [Member]	Mar. 31, 2011 Other Acquisitions Completed in Prior Years [Member]
Acquisitions (Textuals) [Abstract]
Purchase Price				$ 251,500,000			$ 113,800,000
Number of full service lease vehicles				8,000
Number of rental vehicles				5,700
Number of contractual customers acquired				400
Number of trailers included in fleet				9,700
Purchase Price Adjustment			1,800,000
Payments to Acquire Businesses	2,076,000	83,776,000			1,200,000	79,600,000		900,000	4,200,000
Goodwill					28,400,000
Customer relationship intangibles					$ 11,900,000