Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income Statement [Abstract]
OIL AND GAS REVENUES	$ 83,818	$ 50,672	$ 164,533	$ 94,730
COSTS AND EXPENSES
Lease operating	7,031	7,427	15,454	14,093
Production tax	3,128	1,466	6,227	2,407
Ad valorem tax	2,296	981	5,911	1,672
Depreciation, depletion and amortization	43,380	20,595	74,941	37,271
General and administrative (inclusive of stock-based compensation expense of $1,516 and $6,805 for the three months ended June 30, 2012 and 2011, respectively, and $5,532 and $10,655 for the six months ended June 30, 2012 and 2011, respectively)	13,094	14,094	24,632	23,339
Accretion related to asset retirement obligations	170	71	348	145
TOTAL COSTS AND EXPENSES	69,099	44,634	127,513	78,927
OPERATING INCOME	14,719	6,038	37,020	15,803
OTHER INCOME AND EXPENSES
Gain (loss) on derivative instruments, net	38,247	12,065	41,285	11,878
Loss on extinguishment of debt	0	0	0	(897)
Interest expense	(17,686)	(12,407)	(35,022)	(24,615)
Capitalized interest	7,809	5,649	13,832	10,909
Other income (expense), net	225	(1)	(360)	61
INCOME BEFORE INCOME TAXES	43,314	11,344	56,755	13,139
INCOME TAX EXPENSE	(14,810)	(3,602)	(18,828)	(4,662)
NET INCOME	$ 28,504	$ 7,742	$ 37,927	$ 8,477
NET INCOME PER COMMON SHARE
Basic (in dollars per share)	$ 0.72	$ 0.20	$ 0.96	$ 0.22
Diluted (in dollars per share)	$ 0.71	$ 0.20	$ 0.95	$ 0.21
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	39,596	38,898	39,520	38,841
Diluted (in shares)	40,042	39,497	39,987	39,450