CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 66,192	$ 1,056
Accounts receivable	35,654	67,516
Derivative instruments	5,192	40,190
Other current assets	6,756	16,318
Total current assets	113,794	125,080
Oil and natural gas properties, full cost method of accounting:
Proved, net of accumulated depletion of $8,460,589 and $8,237,186	753,079	1,459,312
Unproved	53,645	277,798
Net oil and natural gas properties	806,724	1,737,110
Other property and equipment, net of accumulated depreciation and amortization of $50,058 and $46,908	11,845	17,128
Net property and equipment	818,569	1,754,238
Deferred income taxes	2,230	14,681
Goodwill	134,434	239,420
Derivative instruments	400	8,335
Other assets	48,525	60,108
TOTAL ASSETS	1,117,952	2,201,862
Current liabilities:
Accounts payable and accrued liabilities	141,107	164,786
Accrued interest	6,654	23,407
Derivative instruments	4,542	9,347
Deferred income taxes	2,230	14,681
Current portion of long-term debt	0	12
Other current liabilities	12,201	14,092
Total current liabilities	166,734	226,325
Long-term debt	800,179	1,862,088
Asset retirement obligations	22,629	56,155
Derivative instruments	0	7,204
Other liabilities	73,941	92,914
Total liabilities	1,063,483	2,244,686
Commitments and contingencies (Note 10)
Shareholders’ equity:
Preferred stock, none issued and outstanding	0	0
Common stock, 119,399,983 and 118,245,320 shares issued and outstanding	11,940	11,825
Capital surplus	2,554,997	2,541,859
Accumulated deficit	(2,502,070)	(2,575,994)
Accumulated other comprehensive loss	(10,398)	(20,514)
Total shareholders’ equity (deficit)	54,469	(42,824)
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 1,117,952	$ 2,201,862