Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 11,338		$ 170
Accounts receivable	64,517		67,318
Deferred tax asset	2,815		5,679
Other current assets	10,169		7,370
Total Current Assets	88,839		80,537
Property and Equipment:
Property and Equipment	5,491,252		5,192,793
Less - Accumulated depreciation, depletion, and amortization	(2,968,161)		(2,847,773)
Property and Equipment, Net	2,523,091		2,345,020
Other Long-Term Assets	17,988		18,504
Total Assets	2,629,918		2,444,061
Current Liabilities:
Accounts payable and accrued liabilities	88,419		75,378
Accrued capital costs	104,791		73,190
Accrued interest	21,438		21,362
Undistributed oil and gas revenues	8,634		7,550
Total Current Liabilities	223,282		177,480
Long-Term Debt	1,037,435	[1]	916,934	[1]
Deferred Tax Liabilities	230,617		223,243
Asset Retirement Obligation	68,832		79,643
Other Long-Term Liabilities	10,162		9,901
Commitments and Contingencies	0		0
Stockholders' Equity:
Preferred stock, $0.01 par value	0		0
Common stock, $0.01 par value	439		435
Additional paid-in capital	755,303		747,868
Treasury stock held, at cost	(12,495)		(13,855)
Retained earnings	316,343		302,412
Total Stockholders' Equity	1,059,590		1,036,860
Total Liabilities and Stockholders' Equity	$ 2,629,918		$ 2,444,061

[1] Amounts are shown net of any debt discount or premium