DERIVATIVES AND HEDGING - Summary of Freestanding Derivative Instruments on Income (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gains and losses from freestanding derivative instruments	$ (9,791)	$ 21,480	$ (10,832)	$ 16,716
Investment income
Derivative Instruments, Gain (Loss) [Line Items]
Gains and losses from freestanding derivative instruments	(6,503)	16,206	(4,906)	11,429
General and administrative expense
Derivative Instruments, Gain (Loss) [Line Items]
Gains and losses from freestanding derivative instruments	$ (3,288)	$ 5,274	$ (5,926)	$ 5,287