Long-Term Debt (Details)	12 Months Ended			12 Months Ended		12 Months Ended							12 Months Ended			12 Months Ended					0 Months Ended		1 Months Ended		12 Months Ended		1 Months Ended		1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2010 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2012 US Credit Agreement Revolving Credit Line USD ($)	Dec. 31, 2011 US Credit Agreement Revolving Credit Line USD ($)	Dec. 31, 2012 US Credit Agreement Term Loan USD ($)	Dec. 31, 2011 US Credit Agreement Term Loan USD ($)	Dec. 31, 2012 UK Credit Agreement Revolving Credit Line USD ($)	Dec. 31, 2012 UK Credit Agreement Revolving Credit Line GBP (£)	Dec. 31, 2011 UK Credit Agreement Revolving Credit Line USD ($)	Dec. 31, 2012 UK Credit Agreement Revolving Credit Line Minimum	Dec. 31, 2012 UK Credit Agreement Revolving Credit Line Maximum	Dec. 31, 2012 U.K. Agreement Term Loan GBP (£)	Dec. 31, 2012 U.K. Agreement Term Loan USD ($)	Jan. 31, 2012 U.K. Agreement Term Loan GBP (£)	Dec. 31, 2012 U.K. Agreement Term Loan Minimum	Dec. 31, 2012 U.K. Agreement Term Loan Maximum	Dec. 31, 2012 UK Credit Agreement Overdraft Line of Credit USD ($)	Dec. 31, 2012 UK Credit Agreement Overdraft Line of Credit GBP (£)	Dec. 31, 2011 UK Credit Agreement Overdraft Line of Credit USD ($)	Jun. 25, 2012 3.5% senior subordinated convertible notes due 2026 USD ($)	Jun. 21, 2012 3.5% senior subordinated convertible notes due 2026 USD ($)	Jul. 31, 2012 3.5% senior subordinated convertible notes due 2026 USD ($)	May 31, 2012 3.5% senior subordinated convertible notes due 2026	Dec. 31, 2010 3.5% senior subordinated convertible notes due 2026 USD ($)	Dec. 31, 2011 3.5% senior subordinated convertible notes due 2026 USD ($)	Aug. 31, 2012 5.75% senior subordinated notes due 2022 USD ($)	Dec. 31, 2012 5.75% senior subordinated notes due 2022 USD ($)	Aug. 31, 2012 5.75% senior subordinated notes due 2022 Debt redemption prior to October 1, 2015	Sep. 30, 2012 7.75% senior subordinated notes due 2016 USD ($)	Dec. 31, 2011 7.75% senior subordinated notes due 2016 USD ($)	Dec. 31, 2012 Car rental revolver USD ($)	Dec. 31, 2012 Mortgage facilities USD ($)	Dec. 31, 2011 Mortgage facilities USD ($)	Dec. 31, 2012 Other Debt Securities USD ($)	Dec. 31, 2011 Other Debt Securities USD ($)	Dec. 31, 2012 US Credit Agreement Letters of Credit USD ($)
Long Term Debt
Long-term Debt		$ 937,517,000	$ 850,191,000	$ 50,000,000	$ 132,000,000	$ 110,000,000	$ 127,000,000	$ 48,741,000		$ 59,060,000			£ 24,000,000	$ 38,993,000				$ 6,838,000		$ 13,333,000						$ 63,324,000		$ 550,000,000			$ 375,000,000	$ 23,171,000	$ 104,043,000	$ 75,684,000	$ 5,731,000	$ 4,790,000
Less: current portion		(19,493,000)	(3,414,000)
Net long-term debt		918,024,000	846,777,000
Interest rate (as a percent)																									3.50%	3.50%		5.75%			7.75%
Scheduled maturities of long-term debt for each of the next five years and thereafter
2013		19,493,000
2014		32,928,000
2015		244,028,000
2016		16,477,000
2017		34,677,000
2018 and thereafter		589,914,000
Total long-term debt reported		937,517,000	850,191,000	50,000,000	132,000,000	110,000,000	127,000,000	48,741,000		59,060,000			24,000,000	38,993,000				6,838,000		13,333,000						63,324,000		550,000,000			375,000,000	23,171,000	104,043,000	75,684,000	5,731,000	4,790,000
Maximum credit available				375,000,000					100,000,000						30,000,000				10,000,000																		10,000,000
Base rate of interest on loans				LIBOR		LIBOR		LIBOR	LIBOR									Bank of England Base Rate	Bank of England Base Rate													3 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		500,000																																			500,000
Balance outstanding under credit agreement				50,000,000		110,000,000		55,579,000	34,209,000																							23,171,000
Repayment of debt						17,000,000	7,000,000
Repayment of term loan, quarterly installments													1,500,000
Frequency of principal repayments													Quarterly
Final payment due December 31, 2015													7,500,000
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																											550,000,000
Percentage of principal amount at which the entity may redeem some or all of the notes																								100.00%
Conversion rate of convertible notes																						42.7796
Conversion price per share (in dollars per share)																						$ 23.38
Conversion maximum threshold amount for holder to receive payment in cash equal to the lessor of (i) $1,000 or (ii) The conversion value																						1,000
Conversion minimum threshold amount for the holder to receive payment of cash, common stock or a combination of two																						1,000
Outstanding principal amount of convertible notes																					25,546,000
Settlement of remaining principal and interest on convertible notes in cash																					37,778,000
Conversion balance paid in cash																							24,909,000
Principal amount redeemed																									155,658,000					375,000,000
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%
Pre-tax expense on the extinguishment of debt	1,634,000																								1,634,000					(17,753,000)
Redemption premium																														15,755,000
Write off of unamortized deferred financing costs																														1,998,000
Vehicle financing																																$ 50,000,000