Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
REVENUES
Revenues	$ 130,123	$ 91,549	$ 343,938	$ 279,602
OPERATING EXPENSES
Lease operating	5,312	5,032	22,026	11,943
Production and ad valorem taxes	2,604	2,427	7,226	6,391
Brokered natural gas and marketing expense	3,237	8	3,715	2,474
Depreciation, depletion and amortization	34,270	35,588	98,186	86,929
Exploration	11,328	8,937	36,227	29,514
General and administrative	12,937	11,347	33,391	32,209
Accretion of asset retirement obligations	169	143	486	395
(Gain) loss on sale of assets	6	(13)	(1,814)	(12)
Total operating expenses	108,929	94,338	297,569	262,558
OPERATING INCOME (LOSS)	21,194	(2,789)	46,369	17,044
OTHER INCOME (EXPENSE)
Gain (loss) on derivative instruments	(3,263)	(1,889)	(24,055)	41,385
Interest expense, net	(13,932)	(12,016)	(39,975)	(36,763)
Other income (expense)	(1)		(1)	(19)
Total other income (expense), net	(17,196)	(13,905)	(64,031)	4,603
INCOME (LOSS) BEFORE INCOME TAXES	3,998	(16,694)	(17,662)	21,647
NET INCOME (LOSS)	$ 3,998	$ (16,694)	$ (17,662)	$ 21,647
NET INCOME (LOSS) PER COMMON SHARE
Basic	$ 0.01	$ (0.06)	$ (0.06)	$ 0.08
Diluted	$ 0.01	$ (0.06)	$ (0.06)	$ 0.08
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic	302,154	262,586	299,212	262,044
Diluted	302,548	262,586	299,212	264,717
Oil and Gas [Member]
REVENUES
Revenues	$ 127,179	$ 91,549	$ 340,620	$ 277,174
Brokered Natural Gas and Marketing Revenue [Member]
REVENUES
Revenues	2,944		3,318	2,428
Natural Gas, Gathering, Transportation, Marketing and Processing [Member]
OPERATING EXPENSES
Transportation, gathering and compression	$ 39,066	$ 30,869	$ 98,126	$ 92,715