Long-Term Debt (Schedule Of Long-Term Debt) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012		Jul. 30, 2012
Debt Instrument [Line Items]
Total long-term debt	$ 896,464,000		$ 766,076,000
Stated interest rate					9.25%
Long-term debt unamortized discount	3,500,000		3,900,000
Issued letter of credit in addition to escrow			100,000
9.25% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	296,464,000	[1]	296,076,000	[1]
Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit Agreement, amount outstanding	600,000,000		470,000,000
Letters Of Credit [Member]
Debt Instrument [Line Items]
Credit Agreement, amount outstanding	23,488,000	[2]	23,488,000	[2]
2006 Gulf Coast Acquisition [Member]
Debt Instrument [Line Items]
Issued letter of credit in addition to escrow	$ 3,000,000		$ 23,400,000

[1] The amount is net of unamortized discount of $3.5 million and $3.9 million as of September 30, 2013 and December 31, 2012, respectively

[2] These letters of credit relate to a reclamation deposit requirement of $23.4 million and others totaling $0.1 million. Refer to Note 11 - Commitment and Contingencies for details