CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 19,090	$ 17,650
Accounts receivable, net of allowance for doubtful accounts	132,517	62,978
Derivative assets	9,142	11,292
Other current assets	9,080	4,595
Total current assets	169,829	96,515
Property and equipment, net (successful efforts method)	2,234,256	1,723,359
Derivative assets	4,910	5,181
Other assets	36,008	17,934
Total assets	2,445,003	1,842,989
Current liabilities
Accounts payable and accrued liabilities	183,844	111,655
Derivative liabilities	3,963	0
Deferred income taxes	573	370
Total current liabilities	188,380	112,025
Other liabilities	30,712	28,901
Derivative liabilities	0	1,421
Deferred income taxes	188,524	210,767
Long-term debt	1,142,000	594,759
Shareholders’ equity:
Preferred stock of $100 par value – 100,000 shares authorized; 11,500 shares issued as of June 30, 2013 and December 31, 2012 with a redemption value of $10,000 per share	1,150	1,150
Common stock of $0.01 par value – 128,000,000 shares authorized; 65,278,706 and 55,117,346 shares issued as of June 30, 2013 and December 31, 2012, respectively	465	364
Paid-in capital	894,447	849,046
Retained earnings	519	45,790
Deferred compensation obligation	2,663	3,111
Accumulated other comprehensive loss	(944)	(982)
Treasury stock – 216,558 and 218,320 shares of common stock, at cost, as of June 30, 2013 and December 31, 2012, respectively	(2,913)	(3,363)
Total shareholders’ equity	895,387	895,116
Total liabilities and shareholders’ equity	$ 2,445,003	$ 1,842,989