Debt (Senior Credit Facilities) (Narrative) (Details) (USD $)			3 Months Ended					9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Loans Payable U.S. Term Loans	Jun. 30, 2012 Loans Payable U.S. Term Loans	Mar. 31, 2012 Loans Payable U.S. Term Loans	Dec. 31, 2011 Loans Payable U.S. Term Loans	Nov. 14, 2011 Loans Payable U.S. Term Loans	Sep. 30, 2012 Revolving Credit Facility Revolving Facility	Nov. 14, 2011 Revolving Credit Facility Revolving Facility	Sep. 30, 2012 Swapped To Fixed Rate March Two Thousand Fourteen U.S. Term Loans BasisPoints	Mar. 19, 2012 Swapped To Fixed Rate March Two Thousand Fourteen U.S. Term Loans	Sep. 30, 2012 Swapped to Fixed Rate Two Thousand Sixteen U.S. Term Loans BasisPoints	Jun. 19, 2012 Swapped to Fixed Rate Two Thousand Sixteen U.S. Term Loans	Sep. 30, 2012 Swapped To Fixed Rate January Two Thousand Fourteen U.S. Term Loans BasisPoints	Jan. 17, 2012 Swapped To Fixed Rate January Two Thousand Fourteen U.S. Term Loans
Debt Instrument [Line Items]
Long term debt	$ 4,941,764,000	$ 5,168,226,000	$ 1,179,688,000			$ 1,250,000,000	$ 1,250,000,000				$ 350,000,000		$ 750,000,000		$ 500,000,000
Revolving Facility, maximum borrowing capacity									1,250,000,000
Debt repayment			23,400,000	23,400,000	23,400,000
Revolving Facility, amount outstanding								$ 340,000,000
Interest rate on borrowings								1.82%
Debt instrument basis spread on fixed rate										200		200		200