CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUE
Oil and condensate sales	$ 169,728	$ 142,382	$ 163,538
Natural gas and natural gas liquids sales	190,967	122,836	116,018
Gain (loss) on commodity derivative instruments	26,902	(36,464)	90,288
Lease bonus and other income	42,062	32,079	23,080
TOTAL REVENUE	429,659	260,833	392,924
OPERATING (INCOME) EXPENSE
Lease operating expense	17,280	18,755	21,583
Production costs and ad valorem taxes	47,474	35,464	35,767
Exploration expense	618	645	2,592
Depreciation, depletion and amortization	114,534	102,487	104,298
Impairment of oil and natural gas properties	0	6,775	249,569
General and administrative	77,574	73,139	77,175
Accretion of asset retirement obligations	1,026	892	1,075
(Gain) loss on sale of assets, net	(931)	(4,793)	(4,873)
Other expense	0	0	1,593
TOTAL OPERATING EXPENSE	257,575	233,364	488,779
INCOME (LOSS) FROM OPERATIONS	172,084	27,469	(95,855)
OTHER INCOME (EXPENSE)
Interest and investment income	49	656	58
Interest expense	(15,694)	(7,547)	(6,418)
Other income (expense)	714	(390)	910
TOTAL OTHER EXPENSE	(14,931)	(7,281)	(5,450)
NET INCOME (LOSS)	157,153	20,188	(101,305)
Net income attributable to noncontrolling interests subsequent to initial public offering	34	12	1,260
Distributions on Series A redeemable preferred units subsequent to initial public offering	(3,117)	(5,763)	(7,522)
Distributions on Series B cumulative convertible preferred units	(1,925)	0	0
NET INCOME (LOSS) ATTRIBUTABLE TO THE GENERAL PARTNER AND COMMON AND SUBORDINATED UNITS SUBSEQUENT TO INITIAL PUBLIC OFFERING	152,145	14,437	(108,017)
ALLOCATION OF NET INCOME (LOSS) SUBSEQUENT TO INITIAL PUBLIC OFFERING ATTRIBUTABLE TO:
General partner interest	0	0	0
NET INCOME (LOSS) ATTRIBUTABLE TO THE GENERAL PARTNER AND COMMON AND SUBORDINATED UNITS SUBSEQUENT TO INITIAL PUBLIC OFFERING	152,145	14,437	(108,017)
Predecessor
OTHER INCOME (EXPENSE)
NET INCOME (LOSS)	0	0	(450)
Common Units
ALLOCATION OF NET INCOME (LOSS) SUBSEQUENT TO INITIAL PUBLIC OFFERING ATTRIBUTABLE TO:
Allocation of loss	$ 98,389	$ 24,669	$ (54,326)
NET INCOME (LOSS) ATTRIBUTABLE TO LIMITED PARTNERS PER COMMON AND SUBORDINATED UNIT:
Per unit (basic) (in usd per share)	$ 1.01	$ 0.26	$ (0.56)
Weighted average units outstanding, basic (in shares)	97,400	96,073	96,182
Per unit (diluted) (in usd per share)	$ 1.01	$ 0.26	$ (0.56)
Weighted average units outstanding, diluted (in shares)	97,400	96,243	96,182
DISTRIBUTIONS DECLARED AND PAID SUBSEQUENT TO INITIAL PUBLIC OFFERING:
Per unit (in usd per share)	$ 1.20	$ 1.10	$ 0.42
Subordinated Units
ALLOCATION OF NET INCOME (LOSS) SUBSEQUENT TO INITIAL PUBLIC OFFERING ATTRIBUTABLE TO:
Allocation of loss	$ 53,756	$ (10,232)	$ (53,691)
NET INCOME (LOSS) ATTRIBUTABLE TO LIMITED PARTNERS PER COMMON AND SUBORDINATED UNIT:
Per unit (basic) (in usd per share)	$ 0.56	$ (0.11)	$ (0.56)
Weighted average units outstanding, basic (in shares)	95,149	95,138	95,057
Per unit (diluted) (in usd per share)	$ 0.56	$ (0.11)	$ (0.56)
Weighted average units outstanding, diluted (in shares)	95,149	95,138	95,057
DISTRIBUTIONS DECLARED AND PAID SUBSEQUENT TO INITIAL PUBLIC OFFERING:
Per unit (in usd per share)	$ 0.79	$ 0.74	$ 0.42