Long-Term Debt (Details) In Thousands, unless otherwise specified			6 Months Ended		6 Months Ended		6 Months Ended					6 Months Ended				6 Months Ended					1 Months Ended			1 Months Ended	6 Months Ended
	Jun. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2013 US Credit Agreement Revolving Credit Line USD ($)	Dec. 31, 2012 US Credit Agreement Revolving Credit Line USD ($)	Jun. 30, 2013 US Credit Agreement Term Loan USD ($)	Dec. 31, 2012 US Credit Agreement Term Loan USD ($)	Jun. 30, 2013 UK Credit Agreement Revolving Credit Line	Jun. 30, 2013 UK Credit Agreement Revolving Credit Line GBP (£)	Dec. 31, 2012 UK Credit Agreement Revolving Credit Line USD ($)	Jun. 30, 2013 UK Credit Agreement Revolving Credit Line Minimum	Jun. 30, 2013 UK Credit Agreement Revolving Credit Line Maximum	Jun. 30, 2013 U.K. Agreement Term Loan GBP (£)	Jun. 30, 2013 U.K. Agreement Term Loan USD ($)	Dec. 31, 2012 U.K. Agreement Term Loan USD ($)	Jan. 31, 2012 U.K. Agreement Term Loan GBP (£)	Jun. 30, 2013 U.K. Agreement Term Loan Minimum	Jun. 30, 2013 U.K. Agreement Term Loan Maximum	Jun. 30, 2013 UK Credit Agreement Overdraft Line of Credit	Jun. 30, 2013 UK Credit Agreement Overdraft Line of Credit GBP (£)	Dec. 31, 2012 UK Credit Agreement Overdraft Line of Credit USD ($)	Aug. 31, 2012 5.75% senior subordinated notes due 2022 USD ($)	Jun. 30, 2013 5.75% senior subordinated notes due 2022 USD ($)	Dec. 31, 2012 5.75% senior subordinated notes due 2022 USD ($)	Aug. 31, 2012 5.75% senior subordinated notes due 2022 Debt redemption prior to October 1, 2015	Jun. 30, 2013 Rental Car Revolver USD ($)	Dec. 31, 2012 Rental Car Revolver USD ($)	Jun. 30, 2013 Mortgage facilities USD ($)	Dec. 31, 2012 Mortgage facilities USD ($)	Jun. 30, 2013 Other Debt Securities USD ($)	Dec. 31, 2012 Other Debt Securities USD ($)	Jun. 30, 2013 US Credit Agreement Letters of Credit USD ($)
Long Term Debt
Long-term Debt	$ 920,203	$ 937,517	$ 22,000	$ 50,000	$ 98,000	$ 110,000			$ 48,741			£ 21,000	$ 31,943	$ 38,993						$ 6,838		$ 550,000	$ 550,000		$ 105,286	$ 23,171	$ 102,290	$ 104,043	$ 10,684	$ 5,731
Less: current portion	(44,896)	(19,493)
Net long-term debt	875,307	918,024
Interest rate (as a percent)																						5.75%	5.75%
Maximum credit available			375,000					100,000							30,000				10,000						150,000						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	18,197				0																										0
Balance outstanding under credit agreement			22,000		98,000																				105,286
Repayment of debt					12,000
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
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 (as a percent)																						100.00%