Consolidated statements of operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues:
Oil and natural gas sales	$ 163,625	$ 148,951
Natural gas transportation and treating	80	61
Total revenues	163,705	149,012
Costs and expenses:
Lease operating expenses	22,442	14,984
Production and ad valorem taxes	11,445	8,919
Natural gas transportation and treating	108	43
Drilling and production	674	1,217
General and administrative (including non-cash stock-based compensation of $3,217 and $2,247 for the three months ended March 31, 2013 and 2012, respectively)	19,634	17,531
Accretion of asset retirement obligations	394	264
Depreciation, depletion and amortization	64,503	50,909
Total costs and expenses	119,200	93,867
Operating income	44,505	55,145
Realized and unrealized gain (loss):
Commodity derivative financial instruments, net	(16,854)	594
Interest rate derivatives, net	(6)	(323)
Loss from equity method investee	(64)	0
Interest expense	(25,349)	(14,684)
Interest and other income	15	16
Non-operating income (expense), net	(42,258)	(14,397)
Income (loss) before income taxes	2,247	40,748
Income tax benefit (expense):
Deferred	(1,110)	(14,669)
Total income tax expense	(1,110)	(14,669)
Income from continuing operations	1,137	26,079
Income from discontinued operations, net of tax	272	156
Net income	$ 1,409	$ 26,235
Basic net income per share:
Income from continuing operations, per basic share	$ 0.01	$ 0.21
Income from discontinued operations, net of tax, per basic share	$ 0.00	$ 0.00
Basic (in dollars per share)	$ 0.01	$ 0.21
Diluted net income per share
Income from continuing operations, per diluted share	$ 0.01	$ 0.20
Income from discontinued operations, net of tax, per diluted share	$ 0.00	$ 0.00
Diluted net income per share	$ 0.01	$ 0.20
Weighted average common shares outstanding:
Basic (in shares)	127,200	126,803
Diluted (in shares)	128,851	127,981