Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash	$ 64,545	$ 96,505
Restricted cash	19,439	5,977
Accounts receivable
Oil and natural gas revenues	68,161	65,962
Joint interest billings	61,831	67,225
Other	16,159	8,031
Derivative instruments	49,929	1,190
Lease and well equipment inventory	17,564	5,993
Prepaid expenses and other assets	8,057	6,287
Total current assets	305,685	257,170
Oil and natural gas properties, full-cost method
Evaluated	3,780,236	3,004,770
Unproved and unevaluated	1,199,511	637,396
Midstream and other property and equipment	450,066	281,096
Less accumulated depletion, depreciation and amortization	(2,306,949)	(2,041,806)
Net property and equipment	3,122,864	1,881,456
Other assets
Deferred income taxes	20,457	0
Other assets	6,512	7,064
Total other assets	26,969	7,064
Total assets	3,455,518	2,145,690
Current liabilities
Accounts payable	66,970	11,757
Accrued liabilities	170,855	174,348
Royalties payable	64,776	61,358
Amounts due to affiliates	13,052	10,302
Derivative instruments	0	16,429
Advances from joint interest owners	10,968	2,789
Amounts due to joint ventures	2,373	4,873
Other current liabilities	1,028	750
Total current liabilities	330,022	282,606
Long-term liabilities
Borrowings under Credit Agreement	40,000	0
Long-term Line of Credit	220,000
Borrowings under San Mateo Credit Facility		0
Senior unsecured notes payable	1,037,837	574,073
Asset retirement obligations	29,736	25,080
Derivative instruments	83	0
Deferred income taxes	13,221	0
Other long-term liabilities	4,962	6,385
Total long-term liabilities	1,345,839	605,538
Commitments and contingencies (Note 13)
Shareholders' equity
Common stock — $0.01 par value, 160,000,000 shares authorized; 116,374,503 and 108,513,597 shares issued; and 116,353,590 and 108,510,160 shares outstanding, respectively	1,164	1,085
Additional paid-in capital	1,924,408	1,666,024
Accumulated deficit	(236,277)	(510,484)
Treasury stock, at cost, 20,913 and 3,437 shares, respectively	(415)	(69)
Total shareholders' equity	1,688,880	1,156,556
Non-controlling interest in subsidiaries	90,777	100,990
Total shareholders’ equity	1,779,657	1,257,546
Total liabilities and shareholders’ equity	$ 3,455,518	$ 2,145,690