Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Oil and gas sales	$ 140,892	$ 131,980	$ 287,369	$ 268,122
Price-risk management and other, net	1,574	2,777	1,334	2,513
Total Revenues	142,466	134,757	288,703	270,635
Costs and Expenses:
General and administrative, net	11,191	12,190	23,916	24,073
Depreciation, depletion, and amortization	59,458	61,288	119,578	122,651
Accretion of asset retirement obligation	1,479	1,162	3,254	2,274
Lease operating cost	26,957	24,762	54,381	49,381
Transportation and gas processing	4,865	4,721	10,895	9,315
Severance and other taxes	10,501	12,200	20,276	25,160
Interest expense, net	17,000	13,319	33,802	26,784
Total Costs and Expenses	131,451	129,642	266,102	259,638
Income Before Income Taxes	11,015	5,115	22,601	10,997
Provision for Income Taxes	4,293	2,087	8,670	4,399
Net Income	$ 6,722	$ 3,028	$ 13,931	$ 6,598
Per Share Amounts-
Earnings Per Share (Basic)	$ 0.15	$ 0.07	$ 0.32	$ 0.15
Earnings Per Share (Diluted)	$ 0.15	$ 0.07	$ 0.32	$ 0.15
Weighted Average Shares Outstanding - Basic	43,369	42,862	43,268	42,768
Weighted Average Shares Outstanding - Diluted	43,612	43,111	43,599	43,133