CONSOLIDATED BALANCE SHEET (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 23,400	$ 30,736
Restricted cash	28,094
Accounts receivable, net	222,476	172,419
Inventories	17,468	14,173
Deferred income taxes	81,855
Derivative instruments	3,019	50,824
Other current assets	2,587	2,158
Total current assets	378,899	270,310
Properties and equipment, net (Successful efforts method)	4,546,227	4,310,977
Other assets	55,954	35,026
TOTAL ASSETS	4,981,080	4,616,313
Current liabilities
Accounts payable	288,801	312,480
Current portion of long-term debt		75,000
Accrued liabilities	73,601	49,597
Derivative instruments	13,912	192
Income taxes payable	31,591	1,667
Deferred income taxes		5,203
Total current liabilities	407,905	444,139
Postretirement benefits	33,554	38,864
Long-term debt	1,147,000	1,012,000
Deferred income taxes	1,067,912	882,672
Asset retirement obligation	73,853	67,016
Other liabilities	46,254	40,175
Total liabilities	2,776,478	2,484,866
Commitments and contingencies
Stockholders' equity
Common stock: Authorized -- 480,000,000 shares of $0.10 par value in 2013 and 2012, respectively Issued--422,014,681 shares and 420,859,462 shares in 2013 and 2012, respectively	42,201	42,086
Additional paid-in capital	710,940	695,566
Retained earnings	1,627,805	1,373,264
Accumulated other comprehensive income / (loss)	(8,361)	23,880
Less treasury stock, at cost: 5,618,166 and 808,800 shares in 2013 and 2012, respectively	(167,983)	(3,349)
Total stockholders' equity	2,204,602	2,131,447
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 4,981,080	$ 4,616,313