CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 284	$ 252
Accounts receivable, less allowance for doubtful accounts of $2,493 and $2,374	159,981	167,495
Unrealized derivatives	97,052	137,552
Inventory and other	16,131	22,315
Total current assets	273,448	327,614
Unrealized derivatives	30,467	15,715
Equity method investments	132,115	132,449
Natural gas and oil properties, successful efforts method	8,369,641	8,111,775
Accumulated depletion and depreciation	(2,035,850)	(2,015,591)
Natural gas and oil properties, successful efforts method, net	6,333,791	6,096,184
Transportation and field assets	116,578	117,717
Accumulated depreciation and amortization	(80,371)	(76,150)
Transportation and field assets, net	36,207	41,567
Other assets	124,154	115,206
Total assets	6,930,182	6,728,735
Current liabilities:
Accounts payable	303,618	234,651
Asset retirement obligations	2,366	2,470
Accrued liabilities	133,064	139,379
Deferred tax liability	21,312	37,924
Accrued interest	44,016	36,248
Unrealized derivatives		4,471
Total current liabilities	504,376	455,143
Bank debt	309,000	739,000
Subordinated notes	2,639,835	2,139,185
Deferred tax liability	735,166	698,302
Unrealized derivatives		3,463
Deferred compensation liability	207,906	187,604
Asset retirement obligations and other liabilities	148,116	148,646
Total liabilities	4,544,399	4,371,343
Commitments and contingencies
Stockholders’ Equity
Preferred stock, $1 par, 10,000,000 shares authorized, none issued and outstanding
Common stock, $0.01 par, 475,000,000 shares authorized,163,395,396 issued at June 30, 2013 and 162,641,896 issued at December 31, 2012	1,634	1,626
Common stock held in treasury, 101,301 shares at June 30, 2013 and 127,798 shares at December 31, 2012	(3,751)	(4,760)
Additional paid-in capital	1,934,706	1,915,627
Retained earnings	416,306	360,990
Accumulated other comprehensive income	36,888	83,909
Total stockholders’ equity	2,385,783	2,357,392
Total liabilities and stockholders’ equity	$ 6,930,182	$ 6,728,735