CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities:
Net income	$ 68,373	$ 13,876
Adjustments to reconcile net income to net cash provided from operating activities:
(Gain) loss from equity method investments, net of distributions	(1,552)	2,293
Deferred income tax expense	50,314	11,164
Depletion, depreciation and amortization and impairment	235,837	208,953
Exploration dry hole costs	(159)	817
Mark-to-market on natural gas, NGLs and oil derivatives not designated as hedges	(62,569)	(83,721)
Abandonment and impairment of unproved properties	34,374	63,930
Unrealized derivative loss	3,300	354
Allowance for bad debt	250
Amortization of deferred financing costs, loss on extinguishment of debt and other	16,662	3,893
Deferred and stock-based compensation	63,325	26,341
(Gain) loss on the sale of assets	(83,121)	13,653
Changes in working capital:
Accounts receivable	(13,997)	11,611
Inventory and other	1,545	(2,824)
Accounts payable	(10,381)	(21,922)
Accrued liabilities and other	(22,312)	34,528
Net cash provided from operating activities	279,889	282,946
Investing activities:
Additions to natural gas and oil properties	(592,692)	(781,574)
Additions to field service assets	(2,033)	(1,526)
Acreage purchases	(27,449)	(147,944)
Equity method investments	1,885
Proceeds from disposal of assets	296,068	15,620
Purchases of marketable securities held by the deferred compensation plan	(20,213)	(7,872)
Proceeds from the sales of marketable securities held by the deferred compensation plan	16,342	3,590
Net cash used in investing activities	(328,092)	(919,706)
Financing activities:
Borrowing on credit facilities	893,000	697,000
Repayment on credit facilities	(1,323,000)	(649,000)
Issuance of subordinated notes	750,000	600,000
Repayment of subordinated notes	(259,063)
Dividends paid	(13,057)	(12,972)
Debt issuance costs	(12,324)	(12,455)
Issuance of common stock	343	2,074
Change in cash overdrafts	(1,155)	3,346
Proceeds from the sales of common stock held by the deferred compensation plan	13,491	8,833
Net cash provided from financing activities	48,235	636,826
Increase in cash and cash equivalents	32	66
Cash and cash equivalents at beginning of period	252	92
Cash and cash equivalents at end of period	$ 284	$ 158