UNIT-BASED COMPENSATION (Details) - $ / shares		6 Months Ended	12 Months Ended
	Sep. 23, 2018	Jun. 30, 2020	Dec. 31, 2019
Unvested Units
Vesting (in units)		(159,013)
Forfeited (in units)		(14,166)
Unvested Weighted Average Grant-Date Fair Value
Vesting (in dollars per unit)		$ 18.844
Forfeited (in dollars per unit)		$ 14.349
Long-Term Incentive Plan
Unit-based compensation
Additional common units authorized for issuance	2,500,000
Vesting period		3 years
Authorized issuance of units	4,541,600
Long-Term Incentive Plan | First Anniversary
Unit-based compensation
Vesting percent		33.30%
Long-Term Incentive Plan | Second Anniversary
Unit-based compensation
Vesting percent		33.30%
Long-Term Incentive Plan | Third Anniversary
Unit-based compensation
Vesting percent		33.30%
Long-Term Incentive Plan | Restricted Units
Unvested Units
Unvested at beginning of period (in units)		739,479
Awarded (in units)		946,638
Unvested at end of period (in units)		1,512,938	739,479
Unvested Weighted Average Grant-Date Fair Value
Unvested at beginning of period (in dollars per unit)		$ 18.059
Awarded (in dollars per unit)		11.540
Unvested at end of period (in dollars per unit)		$ 13.932	$ 18.059
Weighted Average Remaining Contractual Term
Unvested contractual term, at end of period		2 years 1 month 28 days	1 year 4 months