EARNINGS PER UNIT - Computations of Net Income (Loss) Per Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income (loss) attributable to OCG Class A unitholders	$ 45,554	$ (16,648)	$ (20,784)	$ 73,050
Weighted average number of Class A units outstanding (basic and diluted) (in shares)	98,677	75,995	98,457	74,005
Basic and diluted net income (loss) per Class A unit (in dollars per share)	$ 0.46	$ (0.22)	$ (0.21)	$ 0.99