Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets
Cash	$ 7,723	$ 6,287
Accounts receivable
Oil and natural gas revenues	33,440	25,823
Joint interest billings	9,322	4,785
Other	1,517	1,066
Derivative instruments	3,929	19
Deferred Tax Assets, Net	0	1,636
Lease and well equipment inventory	1,278	785
Prepaid expenses	1,846	1,771
Total current assets	59,055	42,172
Oil and natural gas properties, full-cost method
Evaluated	1,469,633	1,090,656
Unproved and unevaluated	269,049	194,306
Other property and equipment	35,435	29,910
Less accumulated depletion, depreciation and amortization	(559,965)	(468,995)
Net property and equipment	1,214,152	845,877
Other assets
Derivative instruments	1,278	173
Other assets	2,918	2,108
Total other assets	4,196	2,281
Total assets	1,277,403	890,330
Current liabilities
Accounts payable	15,420	25,358
Accrued liabilities	119,361	63,987
Royalties payable	13,973	7,798
Derivative instruments	0	2,692
Deferred income taxes	802	0
Accrued Income Taxes, Current	2,969	404
Other current liabilities	95	88
Total current liabilities	152,620	100,327
Long-term liabilities
Borrowings under Credit Agreement	250,000	200,000
Asset retirement obligations	10,751	7,309
Derivative Liability, Noncurrent	9	253
Deferred Tax Liabilities, Net, Noncurrent	42,508	10,929
Other long-term liabilities	3,176	2,588
Total long-term liabilities	306,444	221,079
Commitments and contingencies
Shareholders' equity
Common stock - $0.01 par value, 80,000,000 shares authorized; 74,683,934 and 66,958,867 shares issued; and 73,348,734 and 65,652,690 shares outstanding, respectively	747	670
Additional paid-in capital	734,065	548,935
Retained deficit	94,292	30,084
Treasury stock, at cost, 1,335,200 and 1,306,177 shares, respectively	(10,765)	(10,765)
Total shareholders' equity	818,339	568,924
Total liabilities and shareholders' equity	$ 1,277,403	$ 890,330