Debt (Summary Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Credit facility debt	$ 1,547,280		$ 1,598,896
Senior notes	686,917		686,434
Debt including current portion	2,240,147		2,291,280
Less: current portion	5,950		5,950
Total	2,234,197		2,285,330
Term A Facility [Member]
Debt Instrument [Line Items]
Credit facility debt	975,665	[1]	1,025,065	[1]
Term B Facility [Member]
Debt Instrument [Line Items]
Credit facility debt	577,565	[1]	579,781	[1]
Revolving Facility [Member]
Debt Instrument [Line Items]
Borrowing capacity	$ 500,000

[1] The Company's $500,000 revolving credit facility remains undrawn at June 30, 2012. Total undrawn revolver commitments are available to be drawn for general corporate purposes of the Company.