CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 9,194	$ 7,344
Accounts receivable:
Oil and gas sales	20,915	23,792
Severance tax refund	580	3,413
Other	335	249
Prepayments	4,560	2,642
Inventory	6,208	5,713
Commodity derivative contracts	517	4,957
Total current assets	42,309	48,110
Oil and gas properties, on the basis of full-cost accounting:
Proved properties	730,723	644,393
Unevaluated properties	88,470	76,857
Other property and equipment	1,940	1,672
Less accumulated depreciation, depletion, and amortization	(176,870)	(148,843)
Net property and equipment	644,263	574,079
OTHER ASSETS:
Commodity derivative contracts	374	588
Security deposit and other noncurrent assets	1,663	1,879
Total other assets	2,037	2,467
TOTAL	688,609	624,656
CURRENT LIABILITIES:
Accounts payable	49,425	35,731
Accrued liabilities	50,477	37,524
Commodity derivative contracts	22,816	12,599
Current portion of long-term debt	25,000
Total current liabilities	147,718	85,854
LONG-TERM LIABILITIES:
Asset retirement obligations	8,206	7,627
Commodity derivative contracts	13,473	10,178
Long-term debt	209,800	234,800
Mandatorily redeemable convertible preferred units	40,762
Other long-term liabilities	655	695
Total long-term liabilities	272,896	253,300
COMMITMENTS AND CONTINGENCIES (Note 10)
MEMBERS' EQUITY	267,995	285,502
TOTAL	$ 688,609	$ 624,656