CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUE
Revenue from contracts with customers	$ 296,640	$ 492,776	$ 594,737
Gain (loss) on commodity derivative instruments	46,111	(4,955)	14,831
TOTAL REVENUE	342,751	487,821	609,568
OPERATING (INCOME) EXPENSE
Lease operating expense	14,022	17,665
Lease operating expense			18,415
Production costs and ad valorem taxes	43,473	60,533	64,364
Exploration expense	29	397	7,943
Depreciation, depletion, and amortization	82,018	109,584	122,653
Impairment of oil and natural gas properties	51,031	0	0
General and administrative	42,983	63,353	76,712
Accretion of asset retirement obligations	1,131	1,117	1,103
(Gain) loss on sale of assets, net	(24,045)	0	(3)
TOTAL OPERATING EXPENSE	210,642	252,649	291,187
INCOME (LOSS) FROM OPERATIONS	132,109	235,172	318,381
OTHER INCOME (EXPENSE)
Interest and investment income	35	159	183
Interest expense	(10,408)	(21,435)	(20,756)
Other income (expense)	83	472	(2,248)
TOTAL OTHER EXPENSE	(10,290)	(20,804)	(22,821)
NET INCOME (LOSS)	121,819	214,368	295,560
Net (income) loss attributable to noncontrolling interests	0	0	(24)
Distributions on Series A redeemable preferred units	0	0	(25)
Distributions on Series B cumulative convertible preferred units	(21,000)	(21,000)	(21,000)
NET INCOME (LOSS) ATTRIBUTABLE TO THE GENERAL PARTNER AND COMMON AND SUBORDINATED UNITS	100,819	193,368	274,511
ALLOCATION OF NET INCOME (LOSS):
General partner interest	0	0	0
NET INCOME (LOSS) ATTRIBUTABLE TO THE GENERAL PARTNER AND COMMON AND SUBORDINATED UNITS	100,819	193,368	274,511
Common Units
ALLOCATION OF NET INCOME (LOSS):
Allocation of loss	$ 100,819	$ 169,375	$ 154,662
NET INCOME (LOSS) ATTRIBUTABLE TO LIMITED PARTNERS PER COMMON AND SUBORDINATED UNIT:
Per unit (basic) (in usd per share)	$ 0.49	$ 1.01	$ 1.46
Weighted average units outstanding, basic (in shares)	206,705	168,230	106,064
Per unit (diluted) (in usd per share)	$ 0.49	$ 1.01	$ 1.45
Weighted average units outstanding, diluted (in shares)	206,819	168,376	121,264
Subordinated Units
ALLOCATION OF NET INCOME (LOSS):
Allocation of loss	$ 0	$ 23,993	$ 119,849
NET INCOME (LOSS) ATTRIBUTABLE TO LIMITED PARTNERS PER COMMON AND SUBORDINATED UNIT:
Per unit (basic) (in usd per share)	$ 0	$ 0.64	$ 1.25
Weighted average units outstanding, basic (in shares)	0	37,740	96,099
Per unit (diluted) (in usd per share)	$ 0	$ 0.64	$ 1.25
Weighted average units outstanding, diluted (in shares)	0	37,740	96,346
Crude Oil
REVENUE
Revenue from contracts with customers	$ 148,631	$ 263,678	$ 310,278
Natural Gas
REVENUE
Revenue from contracts with customers	138,926	199,265	248,243
Real Estate
REVENUE
Revenue from contracts with customers	$ 9,083	$ 29,833	$ 36,216