Debt (Interest Rates On Outstanding Borrowings Under Term Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term debt	$ 5,773,716	$ 5,431,948
2020 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Long-term debt	1,013,038	1,013,372
U.S. Term Loans | Swapped To Fixed Rate January 2014
Debt Instrument [Line Items]
Long-term debt	500,000	500,000
Debt instrument, interest rate at period end	2.35%	2.35%
U.S. Term Loans | Swapped To Fixed Rate March 2014
Debt Instrument [Line Items]
Long-term debt	350,000	350,000
Debt instrument, interest rate at period end	2.20%	2.20%
U.S. Term Loans | Floating Rate Debt
Debt Instrument [Line Items]
Long-term debt	$ 282,813	$ 306,250
Debt instrument, basis spread on variable rate	1.75%	1.75%
Debt instrument, description of variable rate basis	LIBOR	LIBOR
Debt instrument, interest rate at period end	1.95%	1.96%