Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012 Y	Mar. 31, 2011	Dec. 31, 2011
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts receivable	$ 2,300,000		$ 2,300,000
Internal costs capitalized	4,100,000	3,000,000
Average DD&A per Mcfe	2.24	1.53
Capitalized interest costs associated with unevaluated leasehold and seismic costs	$ 6,023,000	$ 5,260,000
Property and equipment estimated useful life, minimum, in years	5
Reserves discount factor	10.00%
Property and equipment estimated useful life, maximum, in years	10
8.625% Senior Notes Due 2018 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt instrument interest rate	8.625%
4.375% Convertible Senior Notes Due 2028 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt instrument interest rate	4.375%
Stock Options [Member]
Summary Of Significant Accounting Policies [Line Items]
Expiration period after date of grant, in years	ten
Restricted Stock Awards And Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Vesting period for restricted stock awards and units in stock-based compensation, minimum, in years	one
Stock Options And SARs [Member]
Summary Of Significant Accounting Policies [Line Items]
Vesting period, in years	three
Restricted Stock Granted To Contractors [Member]
Summary Of Significant Accounting Policies [Line Items]
Vesting period, in years	three
Minimum [Member] | Stock Appreciation Rights (SARs) [Member]
Summary Of Significant Accounting Policies [Line Items]
Expiration period after date of grant, in years	four
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Vesting period for restricted stock awards and units in stock-based compensation, maximum, in years	three
Maximum [Member] | Stock Appreciation Rights (SARs) [Member]
Summary Of Significant Accounting Policies [Line Items]
Expiration period after date of grant, in years	seven