FAIR VALUE MEASUREMENTS - Changes in Level 3 for Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	$ 248,971	$ 193,608	$ 260,278	$ 153,325
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(25,510)	0	(25,510)	0
Included in net income	(1,748)	2,105	(10,049)	290
Included in OCI	(1,243)	(3,977)	(1,414)	(10,600)
Purchases	11,478	30,300	55,255	84,472
Sales	0	0	(34,532)	0
Settlements/ distributions	(3,845)	(999)	(15,925)	(6,450)
Closing balance	228,103	221,037	228,103	221,037
Change in unrealized investment gains/(losses)	(1,015)	2,139	(14,088)	324
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	4,708	0	5,630
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	0	(422)	0	(1,344)
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements/ distributions	0	0	0	0
Closing balance	0	4,286	0	4,286
Change in unrealized investment gains/(losses)	0	(422)	0	(1,344)
Other liabilities | Derivative instruments
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	4,708	0	5,630
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	0	(422)	0	(1,344)
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements/ distributions	0	0	0	0
Closing balance	0	4,286	0	4,286
Change in unrealized investment gains/(losses)	0	(422)	0	(1,344)
Fixed maturities, available for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	129,046	72,830	119,104	42,894
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	(733)	(34)	(4,043)	(34)
Included in OCI	(1,243)	(3,977)	(1,414)	(10,600)
Purchases	9,717	27,600	34,178	64,832
Sales	0	0	0	0
Settlements/ distributions	(3,319)	(468)	(14,357)	(1,141)
Closing balance	133,468	95,951	133,468	95,951
Change in unrealized investment gains/(losses)	0	0	0	0
Fixed maturities, available for sale | Corporate debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	129,046	72,830	119,104	42,894
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	(733)	(34)	(4,043)	(34)
Included in OCI	(1,243)	(3,977)	(1,414)	(10,600)
Purchases	9,717	27,600	34,178	64,832
Sales	0	0	0	0
Settlements/ distributions	(3,319)	(468)	(14,357)	(1,141)
Closing balance	133,468	95,951	133,468	95,951
Change in unrealized investment gains/(losses)	0	0	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	119,925	120,778	141,174	110,431
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(25,510)	0	(25,510)	0
Included in net income	(1,015)	2,139	(6,006)	324
Included in OCI	0	0	0	0
Purchases	1,761	2,700	21,077	19,640
Sales	0	0	(34,532)	0
Settlements/ distributions	(526)	(531)	(1,568)	(5,309)
Closing balance	94,635	125,086	94,635	125,086
Change in unrealized investment gains/(losses)	(1,015)	2,139	(14,088)	324
Other investments | CLO-Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	4,877	4,808	5,016	5,910
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	333	890	1,236	2,566
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements/ distributions	(526)	(531)	(1,568)	(3,309)
Closing balance	4,684	5,167	4,684	5,167
Change in unrealized investment gains/(losses)	333	890	1,236	2,566
Other investments | Other privately held investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	115,048	115,970	136,158	104,521
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(25,510)	0	(25,510)	0
Included in net income	(1,348)	1,249	(7,242)	(2,242)
Included in OCI	0	0	0	0
Purchases	1,761	2,700	21,077	19,640
Sales	0	0	(34,532)	0
Settlements/ distributions	0	0	0	(2,000)
Closing balance	89,951	119,919	89,951	119,919
Change in unrealized investment gains/(losses)	$ (1,348)	$ 1,249	$ (15,324)	$ (2,242)