CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 38,321	$ 17,650
Accounts receivable, net of allowance for doubtful accounts	147,920	62,978
Derivative assets	4,424	11,292
Other current assets	5,177	4,595
Total current assets	195,842	96,515
Property and equipment, net (successful efforts method)	2,170,122	1,723,359
Derivative assets	1,900	5,181
Other assets	38,572	17,934
Total assets	2,406,436	1,842,989
Current liabilities
Accounts payable and accrued liabilities	223,079	111,655
Derivative liabilities	15,305	0
Deferred income taxes	574	370
Total current liabilities	238,958	112,025
Other liabilities	32,467	28,901
Derivative liabilities	799	1,421
Deferred income taxes	135,429	210,767
Long-term debt	1,203,000	594,759
Commitments and contingencies (Note 11)
Shareholders’ equity:
Preferred stock of $100 par value – 100,000 shares authorized; 11,500 shares issued as of September 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; 65,292,520 and 55,117,346 shares issued as of September 30, 2013 and December 31, 2012, respectively	465	364
Paid-in capital	895,450	849,046
Retained earnings (Accumulated deficit)	(100,106)	45,790
Deferred compensation obligation	2,727	3,111
Accumulated other comprehensive loss	(926)	(982)
Treasury stock – 226,237 and 218,320 shares of common stock, at cost, as of September 30, 2013 and December 31, 2012, respectively	(2,977)	(3,363)
Total shareholders’ equity	795,783	895,116
Total liabilities and shareholders’ equity	$ 2,406,436	$ 1,842,989