Organization and Summary of Significant Accounting Policies (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended				12 Months Ended			12 Months Ended				3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Minimum	Dec. 31, 2012 Minimum Property and equipment other than leasehold improvements	Dec. 31, 2012 Minimum Car rental fleet vehicles	Dec. 31, 2012 Maximum	Dec. 31, 2012 Maximum Property and equipment other than leasehold improvements	Dec. 31, 2012 Maximum Leasehold improvements and equipment under capital lease	Dec. 31, 2012 Maximum Car rental fleet vehicles	Dec. 31, 2011 UK	Sep. 30, 2012 7.75% senior subordinated notes	Dec. 31, 2011 7.75% senior subordinated notes	Dec. 31, 2010 3.5% senior subordinated convertible notes due 2026	Dec. 31, 2011 3.5% senior subordinated convertible notes due 2026	Dec. 31, 2012 5.75% senior subordinated notes due 2022	Dec. 31, 2012 5.75% senior subordinated notes due 2022 Level 2	Dec. 31, 2012 Mortgage facilities	Dec. 31, 2011 Mortgage facilities	Dec. 31, 2012 Mortgage facilities Level 2
Significant Accounting Policies
Pre-tax costs associated with the repurchase and redemption of senior subordinated notes			$ 1,634									$ (17,753)		$ 1,634
Principal amount of senior subordinated notes redeemed												375,000		155,658
Interest rate (as a percent)													7.75%	3.50%	3.50%	5.75%
Net income tax benefit	(94,330)	(71,690)	(63,441)								11,046
Income tax benefit from the resolution of certain tax items in the U.K.											17,008
Reduction of U.K. deferred tax assets	1,380	12,087	904								5,962
Ownership interest in the voting stock of the affiliate (as a percent)				20.00%			50.00%
Property and Equipment
Useful life of property and equipment					3 years	12 months		15 years	40 years	18 months
Fair Value of Financial Instruments
Debt instrument, Carrying Value	937,517	850,191											375,000		63,324	550,000	550,000	104,043	75,684	104,043
Debt instrument, Fair Value																	$ 563,750			$ 105,528