CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities:
Net loss	$ (67,948)	$ (32,673)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, and amortization	48,543	66,970
Deferred income tax	0	1,133
Unrealized losses (gains) on derivative instruments, net	38,311	(5,312)
Ceiling test write-down of natural gas properties	0	34,817
Loss on debt extinguishment	25,223	0
Other, net	5,787	6,971
Changes in operating assets and liabilities:
Accounts receivable	265	6,355
Other current assets	(1,109)	(424)
Accounts payable and accrued liabilities	(14,697)	(11,538)
Accrued interest and other	(53)	27,260
Net cash provided by operating activities	34,322	93,559
Investing activities:
Capital expenditures for property and equipment	(101,933)	(189,634)
Proceeds from sales of assets	313,805	899
Net cash provided (used) by investing activities	211,872	(188,735)
Financing activities:
Proceeds from bank borrowings	202,000	202,000
Repayments of bank borrowings	(127,000)	(92,000)
Redemption of senior notes	(321,315)	0
Change in bank overdrafts	590	(17,284)
Net activity in investments from subsidiaries	0	0
Other, net	(300)	325
Net cash (used) provided by financing activities	(246,025)	93,041
Net increase (decrease) in cash and cash equivalents	169	(2,135)
Cash and cash equivalents at beginning of period	1,056	3,012
Cash and cash equivalents at end of period	1,225	877
Parent Company Net of Eliminations
Operating activities:
Net loss	(72,094)	(15,879)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, and amortization	37,562	47,869
Deferred income tax	0	(10,168)
Unrealized losses (gains) on derivative instruments, net	31,813	(4,171)
Ceiling test write-down of natural gas properties	0	0
Loss on debt extinguishment	25,223	0
Other, net	6,808	7,354
Changes in operating assets and liabilities:
Accounts receivable	(5,361)	8,230
Other current assets	(2,228)	(341)
Accounts payable and accrued liabilities	(14,279)	(11,062)
Accrued interest and other	52	25,174
Net cash provided by operating activities	7,496	47,006
Investing activities:
Capital expenditures for property and equipment	(84,681)	(143,394)
Proceeds from sales of assets	313,803	899
Net cash provided (used) by investing activities	229,122	(142,495)
Financing activities:
Proceeds from bank borrowings	202,000	202,000
Repayments of bank borrowings	(127,000)	(92,000)
Redemption of senior notes	(321,315)	0
Change in bank overdrafts	882	(17,510)
Net activity in investments from subsidiaries	8,251	1,617
Other, net	885	325
Net cash (used) provided by financing activities	(236,297)	94,432
Net increase (decrease) in cash and cash equivalents	321	(1,057)
Cash and cash equivalents at beginning of period	667	1,734
Cash and cash equivalents at end of period	988	677
Guarantor Subsidiary
Operating activities:
Net loss	6,348	19,819
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, and amortization	10,848	18,668
Deferred income tax	0	12,428
Unrealized losses (gains) on derivative instruments, net	6,443	(1,125)
Ceiling test write-down of natural gas properties	0	0
Loss on debt extinguishment	0	0
Other, net	113	87
Changes in operating assets and liabilities:
Accounts receivable	4,735	(2,022)
Other current assets	(1)	(1)
Accounts payable and accrued liabilities	(585)	(1,441)
Accrued interest and other	(90)	2,545
Net cash provided by operating activities	27,811	48,958
Investing activities:
Capital expenditures for property and equipment	(16,962)	(43,102)
Proceeds from sales of assets	0	0
Net cash provided (used) by investing activities	(16,962)	(43,102)
Financing activities:
Proceeds from bank borrowings	0	0
Repayments of bank borrowings	0	0
Redemption of senior notes	0	0
Change in bank overdrafts	(416)	(253)
Net activity in investments from subsidiaries	(10,466)	(5,600)
Other, net	0	0
Net cash (used) provided by financing activities	(10,882)	(5,853)
Net increase (decrease) in cash and cash equivalents	(33)	3
Cash and cash equivalents at beginning of period	45	1
Cash and cash equivalents at end of period	12	4
Combined Non-Guarantor Subsidiaries
Operating activities:
Net loss	(2,202)	(36,613)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, and amortization	133	433
Deferred income tax	0	(1,127)
Unrealized losses (gains) on derivative instruments, net	55	(16)
Ceiling test write-down of natural gas properties	0	34,817
Loss on debt extinguishment	0	0
Other, net	(1,134)	(470)
Changes in operating assets and liabilities:
Accounts receivable	891	147
Other current assets	1,120	(82)
Accounts payable and accrued liabilities	167	965
Accrued interest and other	(15)	(459)
Net cash provided by operating activities	(985)	(2,405)
Investing activities:
Capital expenditures for property and equipment	(290)	(3,138)
Proceeds from sales of assets	2	0
Net cash provided (used) by investing activities	(288)	(3,138)
Financing activities:
Proceeds from bank borrowings	0	0
Repayments of bank borrowings	0	0
Redemption of senior notes	0	0
Change in bank overdrafts	124	479
Net activity in investments from subsidiaries	2,215	3,983
Other, net	(1,185)	0
Net cash (used) provided by financing activities	1,154	4,462
Net increase (decrease) in cash and cash equivalents	(119)	(1,081)
Cash and cash equivalents at beginning of period	344	1,277
Cash and cash equivalents at end of period	$ 225	$ 196