Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Deferred gain on sale of property, current	$ 4,830	$ 0
Current assets
Cash	16,732	8,407
Restricted cash	44,357	609
Accounts receivable
Oil and natural gas revenues	16,616	28,976
Joint interest billings	16,999	6,925
Other	10,794	9,091
Derivative instruments	16,284	55,549
Lease and well equipment inventory	2,022	1,212
Prepaid Expense and Other Assets, Current	3,203	1,649
Total current assets	127,007	112,418
Oil and natural gas properties, full-cost method
Evaluated	2,122,174	1,617,913
Unproved and unevaluated	387,504	264,419
Other property and equipment	86,387	43,472
Less accumulated depletion, depreciation and amortization	(1,583,659)	(603,732)
Net property and equipment	1,012,406	1,322,072
Other assets
Other assets	1,448	0
Total other assets	1,448	0
Total assets	1,140,861	1,434,490
Current liabilities
Accounts payable	10,966	17,526
Accrued liabilities	92,369	107,356
Royalties payable	16,493	14,461
Due to affiliates, current	5,670	2,146
Advances from joint interest owners	700	0
Amounts due to joint ventures	2,793	0
Income taxes payable	2,848	444
Other current liabilities	161	103
Total current liabilities	136,830	142,036
Long-term liabilities
Borrowings under Credit Agreement	0	338,199
Senior unsecured notes payable	391,254	0
Asset retirement obligations	15,166	11,640
Amounts due to joint ventures	3,956	0
Deferred income taxes	0	(73,534)
Deferred gain on sale of property, non-current	102,506	0
Other long-term liabilities	2,190	2,540
Total long-term liabilities	$ 515,072	$ 425,913
Commitments and contingencies (Note 13)
Shareholders' equity
Common stock — $0.01 par value, 120,000,000 and 80,000,000 shares authorized; 85,567,021 and 73,373,744 shares issued; 85,564,435 and 73,342,777 shares outstanding, respectively	$ 856	$ 734
Additional paid-in capital	1,026,077	724,819
Retained (deficit) earnings	(538,930)	140,855
Total shareholders' equity	488,003	866,408
Stockholders' Equity Attributable to Noncontrolling Interest	956	133
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	488,959	866,541
Total liabilities and shareholders' equity	$ 1,140,861	$ 1,434,490