Consolidated Balance Sheets (Audited) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 8,238	$ 54,372
Restricted cash	11,070	2,474
Accounts receivable, net	59,923	53,978
Accounts receivable affiliates	8,518	11,448
Fair value of derivatives	60,809	42,953
Prepaid expenses and other current assets	24,492	11,598
Total current assets	173,050	176,823
Properties and equipment, net	1,301,716	1,008,670
Assets held for sale	148,249	116,559
Fair value of derivatives	41,175	44,464
Accounts receivable affiliates	2,836	8,478
Other assets	30,979	34,041
Total Assets	1,698,005	1,389,035
Current liabilities:
Accounts payable	76,027	47,271
Accounts payable affiliates	10,176	9,605
Production tax liability	18,949	16,226
Fair value of derivatives	27,974	29,998
Funds held for distribution	28,594	29,755
Accrued interest payable	11,243	10,051
Other accrued expenses	22,083	17,723
Total current liabilities	195,046	160,629
Long-term debt	532,157	295,695
Deferred income taxes	207,573	187,999
Asset retirement obligations	46,316	27,797
Fair value of derivatives	21,106	36,644
Accounts payable affiliates	6,134	12,111
Other liabilities	25,561	25,919
Total liabilities	1,033,893	746,794
Shareholders' Equity:
Preferred shares, par value $0.01 per share; authorized 50,000,000 shares; issued: none	0	0
Common shares, par value $0.01 per share; authorized 100,000,000 shares; issued: 23,634,958 in 2011 and 23,462,326 in 2010	236	235
Additional paid-in capital	217,707	209,198
Retained earnings	446,280	432,843
Treasury shares, at cost: 2,938 in 2011 and 2010	(111)	(111)
Total shareholders' equity	664,112	642,165
Noncontrolling interest in subsidiary	0	76
Total equity	664,112	642,241
Total Liabilities and Equity	$ 1,698,005	$ 1,389,035