Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			3 Months Ended														3 Months Ended												3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2013 Accumulated Translation Adjustment [Member]	Mar. 31, 2012 Accumulated Translation Adjustment [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Mar. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Tax Benefit (Provision) [Member] OC before reclassifications [Member]	Mar. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Tax Benefit (Provision) [Member] OC before reclassifications [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Tax Benefit (Provision) [Member] Tax Effect reclassification [Member]	Mar. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Tax Benefit (Provision) [Member] Tax Effect reclassification [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] pre-tax reclassification [Member]	Mar. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] pre-tax reclassification [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Floorplan Interest Expense [Member]	Mar. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Floorplan Interest Expense [Member]	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Expense [Member]	Mar. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Interest Expense [Member]	Mar. 31, 2013 Total [Member]	Mar. 31, 2012 Total [Member]	Mar. 31, 2013 Total [Member] Tax Benefit (Provision) [Member] OC before reclassifications [Member]	Mar. 31, 2012 Total [Member] Tax Benefit (Provision) [Member] OC before reclassifications [Member]	Mar. 31, 2013 Total [Member] Tax Benefit (Provision) [Member] Tax Effect reclassification [Member]	Mar. 31, 2012 Total [Member] Tax Benefit (Provision) [Member] Tax Effect reclassification [Member]	Mar. 31, 2013 Total [Member] pre-tax reclassification [Member]	Mar. 31, 2012 Total [Member] pre-tax reclassification [Member]	Mar. 31, 2013 Total [Member] Floorplan Interest Expense [Member]	Mar. 31, 2012 Total [Member] Floorplan Interest Expense [Member]	Mar. 31, 2013 Total [Member] Interest Expense [Member]	Mar. 31, 2012 Total [Member] Interest Expense [Member]	Mar. 31, 2013 Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Categories of Investments [Domain]	Mar. 31, 2012 Gain (Loss) on Investments, Including Marketable Securities and Investments Held at Cost, Categories of Investments [Domain]
Changes in the balances of each component of accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Foreign Currency Translation, Net of Tax, Beginning Balance	$ (6,126)		$ (7,969)
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Foreign Currency Translation, Net of Tax, Ending Balance			(7,969)	(13,582)	(6,575)
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Marketable Securities, Net of Tax, Beginning Balance	0		8
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Marketable Securities, Net of Tax, Ending Balance			8																											0	11
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Interest Rate Swaps, Net of Tax, Beginning Balance	(26,931)	(19,900)	(21,275)					8	293	(1,025)	(1,134)	(22)	(781)	2,420	2,762	313	263
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Interest Rate Swaps, Net of Tax, Ending Balance	(25,200)	(19,900)	(21,275)			(25,237)	(19,872)	8	293	(1,025)	(1,134)	(22)	(781)	2,420	2,762	313	263
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(33,057)																		(29,236)	8	293	(1,025)	(1,134)	(7,478)	616	2,420	2,762	313	263
Other comprehensive income, net of tax	(5,762)			(7,456)	1,394	1,694	1,403											(5,762)	2,800											0	3
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	$ (38,819)																	$ (38,819)	$ (26,436)	$ 8	$ 293	$ (1,025)	$ (1,134)	$ (7,478)	$ 616	$ 2,420	$ 2,762	$ 313	$ 263