Summary of Signigicant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2012

Accounting Policies [Abstract]

Property and Equipment

(in thousands)	September 30, 2012			December 31, 2011
Property and Equipment
Proved oil and gas properties	$	4,913,556		$	4,343,867
Unproved oil and gas properties	91,415			84,146
Furniture, fixtures, and other equipment	41,297			38,832
Less – Accumulated depreciation, depletion, and amortization	(2,781,965		)	(2,599,079		)
Property and Equipment, Net	$	2,264,303		$	1,867,766

Accounts Payable and Accrued Liabilities

	September 30, 2012		December 31, 2011
Trade accounts payable (1)	$	60,785	$	42,080
Accrued operating expenses	11,328		15,833
Accrued payroll costs	10,984		14,345
Asset retirement obligation – current portion	6,088		9,279
Accrued taxes	8,618		7,604
Other payables	1,803		6,825
Total accounts payable and accrued liabilities	$	99,606	$	95,966

(1) Included in “trade accounts payable” are liabilities of approximately $28.3 million and $18.7 million at September 30, 2012 and December 31, 2011, respectively, for outstanding checks.

Accumulated other comprehensive income and related tax effects

	Gross Value			Tax Effect			Net of Tax Value
Other comprehensive loss at December 31, 2011	$	—		$	—		$	—
Change in fair value of cash flow hedges	1,237			450			787
Effect of cash flow hedges settled during the period	(1,415		)	(515		)	(900		)
Other comprehensive loss at September 30, 2012	$	(178	)	$	(65	)	$	(113	)

Roll-forward of our asset retirement obligations

	2012
Asset Retirement Obligation recorded as of January 1	$	76,393
Accretion expense	3,465
Liabilities incurred for new wells and facilities construction	1,148
Reductions due to abandoned wells	(1,692		)
Revisions in estimates	3,978
Asset Retirement Obligation as of September 30	$	83,292