Earnings Per Unit - Computation of Basic and Diluted Earnings per Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share Basic [Line Items]
Net income (loss)	$ 76,112	$ 9,017
Distributions on Series B cumulative convertible preferred units	(5,250)	(5,250)
NET INCOME (LOSS) ATTRIBUTABLE TO THE GENERAL PARTNER AND COMMON AND SUBORDINATED UNITS	70,862	3,767
ALLOCATION OF NET INCOME (LOSS):
General partner interest	0	0
NET INCOME (LOSS) ATTRIBUTABLE TO THE GENERAL PARTNER AND COMMON AND SUBORDINATED UNITS	70,862	3,767
Common Units
ALLOCATION OF NET INCOME (LOSS):
Allocation of net income (loss)	$ 70,862	$ 1,905
Weighted average common units outstanding:
Weighted average units outstanding (basic) (in shares)	206,631	109,420
Effect of dilutive securities (in shares)	0	615
Weighted average units outstanding (diluted) (in shares)	206,631	110,035
NET INCOME (LOSS) ATTRIBUTABLE TO LIMITED PARTNERS PER COMMON AND SUBORDINATED UNIT:
Per unit (basic) (in dollars per share)	$ 0.34	$ 0.02
Per unit (diluted) (in dollars per share)	$ 0.34	$ 0.02
Subordinated units
ALLOCATION OF NET INCOME (LOSS):
Allocation of net income (loss)	$ 0	$ 1,862
Weighted average common units outstanding:
Weighted average units outstanding (basic) (in shares)	0	96,329
Effect of dilutive securities (in shares)	0	0
Weighted average units outstanding (diluted) (in shares)	0	96,329
NET INCOME (LOSS) ATTRIBUTABLE TO LIMITED PARTNERS PER COMMON AND SUBORDINATED UNIT:
Per unit (basic) (in dollars per share)	$ 0	$ 0.02
Per unit (diluted) (in dollars per share)	$ 0	$ 0.02