INVESTMENTS - Fixed Maturities Held to Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Held to maturity
Amortized cost	$ 712,840	$ 698,351
Allowance for expected credit losses	0	0
Net carrying value	712,840	698,351
Gross unrealized gains	41	0
Gross unrealized losses	(16,242)	(23,608)
Fair value	696,639	674,743
Corporate debt
Held to maturity
Amortized cost	90,200	85,200
Allowance for expected credit losses	0	0
Net carrying value	90,200	85,200
Gross unrealized gains	0	0
Gross unrealized losses	(12,779)	(11,428)
Fair value	77,421	73,772
ABS
Held to maturity
Amortized cost	622,640	613,151
Allowance for expected credit losses	0	0
Net carrying value	622,640	613,151
Gross unrealized gains	41	0
Gross unrealized losses	(3,463)	(12,180)
Fair value	$ 619,218	$ 600,971