Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 15,555	$ 26,358
Accounts receivable:
Joint interest and other	14,437	5,959
Oil and natural gas sales	23,533	8,081
Related party	1,303	772
Inventories	5,631	6,195
Deferred income taxes	112	1,857
Derivative instruments	213	0
Prepaid expenses and other	1,184	1,053
Total current assets	61,968	50,275
Property and equipment
Oil and natural gas properties, based on the full cost method of accounting ($369,561 and $121,245 excluded from amortization at December 31, 2013 and December 31, 2012, respectively)	1,648,360	697,742
Pipeline and gas gathering assets	6,142	0
Other property and equipment	4,071	2,337
Accumulated depletion, depreciation, amortization and impairment	(212,236)	(145,837)
Property and equipment, net of accumulated depreciation, depletion, amortization and impairment	1,446,337	554,242
Derivative instruments	218	0
Other assets	13,091	2,184
Total assets	1,521,614	606,701
Current liabilities:
Accounts payable-trade	2,679	12,141
Accounts payable-related party	17	18,813
Accrued capital expenditures	74,649	29,397
Other accrued liabilities	34,750	10,649
Revenues and royalties payable	9,225	3,270
Derivative instruments	0	4,817
Note payable-short term	0	145
Total current liabilities	121,320	79,232
Long-term debt	460,000	193
Derivative instruments	0	388
Asset retirement obligations	2,989	2,125
Deferred income taxes	91,764	62,695
Total liabilities	676,073	144,633
Commitments and contingencies (Note 14)
Stockholders’ equity:
Common stock, $0.01 par value, 100,000,000 shares authorized, 47,106,216 issued and outstanding at December 31, 2013; 36,986,532 issued and outstanding at December 31, 2012	471	370
Additional paid-in capital	842,557	513,772
Retained earnings (accumulated deficit)	2,513	(52,074)
Total stockholders’ equity	845,541	462,068
Total liabilities and stockholders’ equity	$ 1,521,614	$ 606,701