Long-Term Debt (Details) In Thousands, unless otherwise specified			3 Months Ended		3 Months Ended		3 Months Ended					3 Months Ended				3 Months Ended					1 Months Ended			1 Months Ended	3 Months Ended							3 Months Ended
	Mar. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Mar. 31, 2013 US Credit Agreement Revolving Credit Line USD ($)	Dec. 31, 2012 US Credit Agreement Revolving Credit Line USD ($)	Mar. 31, 2013 US Credit Agreement Term Loan USD ($)	Dec. 31, 2012 US Credit Agreement Term Loan USD ($)	Mar. 31, 2013 UK Credit Agreement Revolving Credit Line USD ($)	Mar. 31, 2013 UK Credit Agreement Revolving Credit Line GBP (£)	Dec. 31, 2012 UK Credit Agreement Revolving Credit Line USD ($)	Mar. 31, 2013 UK Credit Agreement Revolving Credit Line Minimum	Mar. 31, 2013 UK Credit Agreement Revolving Credit Line Maximum	Mar. 31, 2013 U.K. Agreement Term Loan GBP (£)	Mar. 31, 2013 U.K. Agreement Term Loan USD ($)	Dec. 31, 2012 U.K. Agreement Term Loan USD ($)	Jan. 31, 2012 U.K. Agreement Term Loan GBP (£)	Mar. 31, 2013 U.K. Agreement Term Loan Minimum	Mar. 31, 2013 U.K. Agreement Term Loan Maximum	Mar. 31, 2013 UK Credit Agreement Overdraft Line of Credit	Mar. 31, 2013 UK Credit Agreement Overdraft Line of Credit GBP (£)	Dec. 31, 2012 UK Credit Agreement Overdraft Line of Credit USD ($)	Aug. 31, 2012 5.75% senior subordinated notes due 2022 USD ($)	Mar. 31, 2013 5.75% senior subordinated notes due 2022 USD ($)	Dec. 31, 2012 5.75% senior subordinated notes due 2022 USD ($)	Aug. 31, 2012 5.75% senior subordinated notes due 2022 Debt redemption prior to October 1, 2015	Mar. 31, 2013 Rental Car Revolver USD ($)	Dec. 31, 2012 Rental Car Revolver USD ($)	Mar. 31, 2013 Mortgage facilities USD ($)	Dec. 31, 2012 Mortgage facilities USD ($)	Mar. 31, 2013 Other Debt Securities USD ($)	Dec. 31, 2012 Other Debt Securities USD ($)	Mar. 31, 2013 US Credit Agreement Letters of Credit USD ($)	Mar. 31, 2013 7.75% senior subordinated notes due 2016 USD ($)
Long Term Debt
Long-term Debt	$ 891,729	$ 937,517	$ 10,000	$ 50,000	$ 110,000	$ 110,000	$ 3,040		$ 48,741			£ 22,500	$ 34,205	$ 38,993						$ 6,838		$ 550,000	$ 550,000		$ 72,950	$ 23,171	$ 103,205	$ 104,043	$ 8,329	$ 5,731
Less: current portion	(33,053)	(19,493)
Net long-term debt	858,676	918,024
Interest rate (as a percent)																						5.75%										7.75%
Maximum credit available			375,000					100,000							30,000				10,000												10,000
Base rate of interest on loans			LIBOR		LIBOR		LIBOR	LIBOR										Bank of England Base Rate	Bank of England Base Rate						three-month LIBOR
Line of credit basis spread on variable rate (as a percent)			2.25%		2.25%					1.35%	3.00%							1.75%	1.75%						2.50%
Incremental interest rate for uncollateralized borrowings in excess of maximum limit (as a percent)			1.25%
Letters of credit outstanding	500																														500
Balance outstanding under credit agreement			10,000		110,000		3,040	2,000																	72,950
Repayment of term loan, quarterly installments												1,500
Frequency of principal repayments												Quarterly
Final payment due December 31, 2015												7,500
Low end of interest rate, depending on UK subsidiaries ratios (as a percent)																2.675%
High end of interest rate, depending on UK subsidiaries ratios (as a percent)																	4.325%
Debt issued																					550,000
Principal amount redeemed																																375,000
Specified equity offerings, percentage of debt which may be redeemed																								40.00%
Change of control, redemption price as a percentage of principal																					101.00%
Sale of assets, redemption price as percentage of principal																					100.00%
Domestic Subsidiaries ownership guaranteeing obligations																						100.00%
Vehicle financing																									$ 100,000