Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Cash flows from operating activities:
Net income	$ 15,835		$ (19,924)
Adjustments to net income to reconcile to net cash provided by operating activities:
Unrealized gain on derivatives, net	(1,533)		27,745
Depreciation, depletion and amortization	39,814		32,357
Amortization and impairment of natural gas and crude oil properties	653		453
Exploratory dry hole costs	0		35
Loss (gain) from sale of properties and equipment	(20,489)		(3,928)
Deferred income taxes	10,914		(14,024)
Stock-based compensation	1,946		1,545
Amortization of debt issuance costs	1,641		1,704
Other	699		136
Changes in assets and liabilities	(5,181)		(10,623)
Net cash provided by operating activities	44,299		15,476
Cash flows from investing activities:
Capital expenditures	(107,029)		(71,079)
Acquisition of natural gas and crude oil properties, net of cash acquired	(10,000)		0
Proceeds from sale of properties and equipment	184,646		9,952
Increase in restricted cash			(101)
Net cash used in investing activities	67,617		(61,228)
Cash flows from financing activities:
Proceeds from credit facility	144,750		0
Payment of credit facility	(263,000)		0
Contribution by investing partner in PDCM	0		6,407
Other	(249)		(328)
Net cash provided by financing activities	(118,499)		6,079
Net decrease in cash and cash equivalents	(6,583)		(39,673)
Cash and cash equivalents, beginning of period	8,238	[1]
Cash and cash equivalents, end of period	1,655		14,699
Cash payments (receipts) for:
Interest, net of capitalized interest	14,975		12,314
Income taxes, net of refunds	(1,100)		85
Non-cash investing activities:
Change in accounts payable related to purchases of properties and equipment	(21,044)		5,832
Change in asset retirement obligation, with a corresponding increase to natural gas and crude oil properties, net of disposals	$ (1,962)		$ 229

[1] Derived from audited 2011 balance sheet.