Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 65,678	$ 154,695
Restricted cash	20,113	30,270
Accounts receivable (net of allowance of $225 and $225, respectively)	70,628	92,737
Deferred tax asset	480	8,191
Derivative asset	2,194	1,688
Other current assets	28,050	26,408
Total current assets	187,143	313,989
Oil and gas properties (using the successful efforts method of accounting):
Proved properties	4,875,232	4,291,440
Unproved properties	22,945	20,402
Total oil and gas	4,898,177	4,311,842
Less accumulated depletion, depreciation, impairment and amortization	(1,760,756)	(1,407,206)
Oil and gas properties, net	3,137,421	2,904,636
Restricted cash	10,000	10,000
Deferred financing costs, net	40,873	48,353
Other assets, net	13,337	13,124
Total assets	3,388,774	3,290,102
Liabilities and Equity
Accounts payable and accruals	265,620	230,703
Current maturities of long-term debt	33,848	21,625
Asset retirement obligation	52,536	43,386
Deferred tax liability	138
Derivative liability	68,816	37,893
Current maturities of other long-term obligations	113,657	86,521
Total current liabilities	534,615	420,128
Long-term debt	1,976,157	1,857,784
Other long-term obligations	451,797	472,500
Asset retirement obligation	115,981	123,472
Deferred tax liability	27,493	16,956
Derivative liability	522	6,425
Total liabilities	3,106,565	2,897,265
Commitments and contingencies (Note 12)
Temporary equity:
Redeemable noncontrolling interest	115,820	140,851
8% convertible perpetual preferred stock: $0.001 par value; 806,847 issued and outstanding at December 31, 2011; None issued at December 31, 2010; Liquidation value of $80.7 million	70,055
Shareholders' equity:
8% convertible perpetual preferred stock: $0.001 par value, 10,000,000 shares authorized; 2,318,153 issued and outstanding at December 31, 2011; 1,400,000 issued and outstanding at December 31, 2010. Liquidation value of $231.8 million and $140.0 million at December 31, 2011 and 2010, respectively.	222,681	140,000
Common stock: $0.001 par value, 100,000,000 shares authorized; 52,034,547 issued and 51,958,707 outstanding at December 31, 2011; 51,347,163 issued and 51,271,323 outstanding at December 31, 2010	52	51
Additional paid-in capital	529,669	570,739
Accumulated deficit	(548,765)	(356,866)
Accumulated other comprehensive loss	(106,392)	(101,027)
Treasury stock, at cost	(911)	(911)
Total shareholders' equity	96,334	251,986
Total liabilities and equity	$ 3,388,774	$ 3,290,102