Long-Term Debt (Schedule Of Long-Term Debt) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Jul. 30, 2012	Dec. 31, 2011	Nov. 08, 2012 Revolving Credit Facility [Member]	Sep. 30, 2012 Revolving Credit Facility [Member]	Dec. 31, 2011 Revolving Credit Facility [Member]	Sep. 30, 2012 Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Senior revolving credit facility				$ 325,000,000	$ 325,000,000	$ 500,000,000
9.25% Senior Notes due 2020							295,946,000	[1]
Total long-term debt	620,946,000		500,000,000
Senior notes stated interest rate		9.25%
Senior notes maturity date	Nov. 30, 2020
Senior notes unamortized discount	$ 4,100,000

[1] The amount is net of unamortized discount of $4.1 million as of September 30, 2012.