Long-term Debt - Credit Facility and Term Loan (Details) (USD $)									12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Senior Secured Credit Facility	Aug. 02, 2011 Senior Secured Credit Facility	Dec. 31, 2012 Term Loan	Dec. 31, 2012 Term Loan LIBOR	Dec. 31, 2012 Term Loan Base Rate	Dec. 31, 2012 Letter of Credit	Dec. 31, 2012 Minimum Senior Secured Credit Facility	Dec. 31, 2012 Minimum Senior Secured Credit Facility LIBOR	Dec. 31, 2012 Minimum Senior Secured Credit Facility Base Rate	Dec. 31, 2012 Minimum Term Loan LIBOR	Dec. 31, 2012 Maximum Senior Secured Credit Facility	Dec. 31, 2012 Maximum Senior Secured Credit Facility LIBOR	Dec. 31, 2012 Maximum Senior Secured Credit Facility Base Rate
Long-term Debt
Line of Credit Facility, Maximum Borrowing Capacity				$ 410,000,000
Line of Credit Facility, Amount Outstanding								8,600,000
Basis Spread on Interest Rate						3.00%	1.50%			1.75%	0.25%	1.00%		3.50%	2.00%
Commitment fee percentage									0.25%				0.75%
Maximum consolidated total leverage			6.75
Minimum consolidated interest coverage ratio			1.75
Maximum consolidated senior secured debt ratio			2.75
Senior Unsecured Debt Limit			1,500,000,000
Maximum consolidated total leverage ratio			6.00
Maximum outstanding equity interests of foreign restricted subsidiaries			66.00%
Cash and other assets	37,800,000
Debt Instrument, Face Amount					325,000,000
Current portion of long-term debt	$ 3,250,000	$ 111,000			$ 3,250,000
Amended Line of Credit Facility, Covenant, Maximum Consolidated Total Leverage			4.50
Amended Line of Credit Facility, Covenant, Minimum Consolidated Total Leverage			2.00