Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 701	$ 1,852
Accounts receivable, net of allowance for doubtful accounts of $735 and $688 at September 30, 2015 and December 31, 2014, respectively	99,297	157,678
Inventories	18,184	14,251
Assets held for sale	0	395,797
Derivative instruments	153,816	322,337
Prepayments and other	12,667	27,445
Total current assets	284,665	919,360
Oil and natural gas properties, successful efforts method
Proved properties	7,754,455	6,903,514
Unproved properties	172,897	142,340
Less accumulated depreciation, depletion and amortization	2,744,855	1,893,106
Oil and natural gas properties, net	5,182,497	5,152,748
Other property and equipment, net	48,739	46,389
Total property, plant and equipment, net	5,231,236	5,199,137
Noncurrent derivative instruments	2,517	0
Other assets	13,129	19,761
TOTAL ASSETS	5,531,547	6,138,258
Current Liabilities
Accounts payable	79,623	101,453
Accrued taxes	27,555	5,530
Accrued wages and benefits	25,103	21,553
Accrued capital costs	101,486	207,461
Revenue and royalty payable	58,480	72,047
Liabilities related to assets held for sale	0	24,230
Pension liabilities	29,789	24,609
Deferred income taxes	9,908	79,164
Derivative instruments	3,079	988
Other	13,513	23,288
Total current liabilities	348,536	560,323
Long-term debt	750,081	1,038,563
Asset retirement obligations	100,781	94,060
Pension and other postretirement liabilities	734	15,935
Deferred income taxes	853,360	1,000,486
Noncurrent derivative instruments	2,924	0
Other long-term liabilities	10,234	14,287
Total liabilities	$ 2,066,650	$ 2,723,654
Commitments and Contingencies
Shareholders’ Equity
Preferred stock, cumulative, $0.01 par value, 5,000,000 shares authorized	$ 0	$ 0
Common shareholders’ equity
Common stock, $0.01 par value; 150,000,000 shares authorized; 81,767,862 shares and 75,875,711 shares issued at September 30, 2015 and December 31, 2014, respectively	818	759
Premium on capital stock	975,616	564,438
Retained earnings	2,638,397	2,997,821
Accumulated other comprehensive income (loss), net of tax
Pension and postretirement plans	(19,969)	(22,870)
Deferred compensation plan	1,923	2,862
Treasury stock, at cost; 3,019,498 shares and 2,980,598 shares at September 30, 2015 and December 31, 2014, respectively	(131,888)	(128,406)
Total shareholders’ equity	3,464,897	3,414,604
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 5,531,547	$ 6,138,258