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
OIL AND GAS REVENUES	$ 134,224	$ 83,818	$ 246,125	$ 164,533
COSTS AND EXPENSES
Lease operating	11,797	7,031	21,992	15,454
Production tax	4,584	3,128	9,097	6,227
Ad valorem tax	2,863	2,296	4,723	5,911
Depreciation, depletion and amortization	50,408	43,380	95,998	74,941
General and administrative (inclusive of stock-based compensation expense of $2,983 and $1,516 for the three months ended June 30, 2013 and 2012, respectively, and $9,466 and $5,532 for the six months ended June 30, 2013 and 2012, respectively)	17,834	13,085	34,007	24,620
Accretion related to asset retirement obligations	120	92	227	194
TOTAL COSTS AND EXPENSES	87,606	69,012	166,044	127,347
OPERATING INCOME	46,618	14,806	80,081	37,186
OTHER INCOME AND EXPENSES
Gain (loss) on derivative instruments, net	25,726	37,890	11,172	41,693
Interest expense	(21,519)	(16,767)	(43,271)	(33,224)
Capitalized interest	7,530	6,011	14,306	12,034
Other income, net	27	22	67	234
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	58,382	41,962	62,355	57,923
INCOME TAX EXPENSE	(22,545)	(16,279)	(23,994)	(21,564)
NET INCOME FROM CONTINUING OPERATIONS	35,837	25,683	38,361	36,359
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES	1,132	2,821	24,790	1,568
NET INCOME	$ 36,969	$ 28,504	$ 63,151	$ 37,927
NET INCOME PER COMMON SHARE - BASIC
Net income from continuing operations - basic (in dollars per share)	$ 0.89	$ 0.65	$ 0.96	$ 0.92
Net income from discontinued operations - basic (in dollars per share)	$ 0.03	$ 0.07	$ 0.62	$ 0.04
Net income per share, basic (in dollars per share)	$ 0.92	$ 0.72	$ 1.58	$ 0.96
NET INCOME PER COMMON SHARE - DILUTED
Net income from continuing operations - diluted (in dollars per share)	$ 0.88	$ 0.64	$ 0.95	$ 0.91
Net income from discontinued operations - diluted (in dollars per share)	$ 0.03	$ 0.07	$ 0.61	$ 0.04
Net income per share, diluted (in dollars per share)	$ 0.91	$ 0.71	$ 1.56	$ 0.95
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	40,078	39,596	39,928	39,520
Diluted (in shares)	40,610	40,042	40,469	39,987