Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets
Cash	$ 14,635	$ 6,287
Accounts receivable
Oil and natural gas revenues	33,493	25,823
Joint interest billings	9,925	4,785
Other	1,594	1,066
Derivative instruments	22	19
Deferred Tax Assets, Net	4,294	1,636
Lease and well equipment inventory	954	785
Prepaid expenses	2,427	1,771
Total current assets	67,344	42,172
Oil and natural gas properties, full-cost method
Evaluated	1,278,003	1,090,656
Unproved and unevaluated	277,949	194,306
Other property and equipment	32,219	29,910
Less accumulated depletion, depreciation and amortization	(524,822)	(468,995)
Net property and equipment	1,063,349	845,877
Other assets
Derivative instruments	171	173
Other assets	2,577	2,108
Total other assets	2,748	2,281
Total assets	1,133,441	890,330
Current liabilities
Accounts payable	18,541	25,358
Accrued liabilities	105,129	63,987
Royalties payable	13,687	7,798
Derivative instruments	10,264	2,692
Accrued Income Taxes, Current	3,219	404
Other current liabilities	88	88
Total current liabilities	150,928	100,327
Long-term liabilities
Borrowings under Credit Agreement	150,000	200,000
Asset retirement obligations	9,723	7,309
Derivative Liability, Noncurrent	1,025	253
Deferred Tax Liabilities, Net, Noncurrent	30,942	10,929
Other long-term liabilities	3,581	2,588
Total long-term liabilities	195,271	221,079
Commitments and contingencies
Shareholders' equity
Common stock - $0.01 par value, 80,000,000 shares authorized; 74,657,951 and 66,958,867 shares issued; and 73,327,906 and 65,652,690 shares outstanding, respectively	747	670
Additional paid-in capital	732,587	548,935
Retained deficit	64,673	30,084
Treasury stock, at cost, 1,330,045 and 1,306,177 shares, respectively	(10,765)	(10,765)
Total shareholders' equity	787,242	568,924
Total liabilities and shareholders' equity	$ 1,133,441	$ 890,330