Long-Term Debt (Schedule of Debt) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Debt Instrument [Line Items]
Discount	$ (20,700,000)		$ (20,700,000)		$ (23,300,000)
Total Long-term Debt	1,209,700,000		1,209,700,000		1,209,500,000
Less current maturities	(4,720,000)		(4,720,000)		(7,420,000)
Long-term debt, less current maturities	1,204,998,000		1,204,998,000		1,202,063,000
Debt Instruments (Narrative) [Abstract]
Debt modification costs	0	0	1,296,000	0
Senior Secured Credit Facility, due Oct 2017, variable rate 3.75%
Debt Instrument [Line Items]
Debt interest rate (percent)	3.75%		3.75%
Senior secured credit facility due	469,600,000		469,600,000
Senior Secured Credit Facility, due Oct 2017, variable rate 4.25%
Debt Instrument [Line Items]
Debt interest rate (percent)					4.25%
Senior secured credit facility due					472,000,000
Senior Notes due Oct 2018, at a fixed rate 9.5%
Debt Instrument [Line Items]
Debt interest rate (percent)	9.50%		9.50%		9.50%
Senior Notes due October 2018, at a fixed rate of 9.5%	$ 760,800,000		$ 760,800,000		$ 760,800,000