Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 5,956	$ 8,238	[1]
Restricted cash	2,240	11,070	[1]
Accounts receivable, net	56,345	59,923	[1]
Accounts receivable affiliates	7,438	8,518	[1]
Fair value of derivatives	71,217	60,809	[1]
Prepaid expenses and other current assets	10,674	24,492	[1]
Total current assets	153,870	173,050	[1]
Properties and equipment, net	1,680,411	1,301,716	[1]
Assets held for sale	0	148,249	[1]
Fair value of derivatives	35,920	41,175	[1]
Accounts receivable affiliates	1,437	2,836	[1]
Other assets	46,190	30,979	[1]
Total Assets	1,917,828	1,698,005	[1]
Current liabilities:
Accounts payable	53,233	76,027	[1]
Accounts payable affiliates	10,600	10,176	[1]
Production tax liability	27,189	18,949	[1]
Fair value of derivatives	18,155	27,974	[1]
Funds held for distribution	29,368	28,594	[1]
Accrued interest payable	10,249	11,243	[1]
Other accrued expenses	33,255	22,083	[1]
Total current liabilities	182,049	195,046	[1]
Long-term debt	591,976	532,157	[1]
Deferred income taxes	192,733	207,573	[1]
Asset retirement obligations	59,856	46,316	[1]
Fair value of derivatives	13,575	21,106	[1]
Accounts payable affiliates	3,284	6,134	[1]
Other liabilities	15,511	25,561	[1]
Total liabilities	1,058,984	1,033,893	[1]
Commitments and contingent liabilities			[1]
Shareholders' Equity:
Preferred shares - par value $0.01 per share, 50,000,000 shares authorized,none issued	0	0	[1]
Common shares, par value $0.01 per share, authorized 100,000,000 shares; issued: 30,261,150 in 2012 and 23,634,958 in 2011	303	236	[1]
Additional paid-in capital	384,275	217,707	[1]
Retained earnings	474,386	446,280	[1]
Treasury shares - at cost, 3,204 and 2,938 as of June 30, 2012 and December31, 2011, respectively	(120)	(111)	[1]
Total shareholders' equity	858,844	664,112	[1]
Total Liabilities and Equity	$ 1,917,828	$ 1,698,005	[1]

[1] Derived from audited 2011 balance sheet.