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FAIR VALUE MEASUREMENTS - Summary of Changes in Level 3 for Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	$ 260,278	$ 153,325
Transfers into Level 3	0	0
Transfers out of Level 3	(25,510)	0
Included in net income	(16,036)	16,153
Included in OCI	2,438	(9,014)
Purchases	59,250	110,121
Sales	(35,302)	0
Settlements/ distributions	(16,776)	(10,307)
Closing balance	$ 228,342	$ 260,278
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment income, Net investment gains (losses)	Net investment income, Net investment gains (losses)
FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfOtherComprehensiveIncomeExtensibleListNotDisclosedFlag	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment income, Net investment gains (losses)	Net investment income, Net investment gains (losses)
Change in unrealized gain/(losses)	$ (15,591)	$ 16,257
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	5,630
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	0	(3,542)
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	(2,088)
Closing balance	$ 0	$ 0
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment income, Net investment gains (losses)	Net investment income, Net investment gains (losses)
Change in unrealized gains/(losses)	$ 0	$ 0
Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	119,104	42,894
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(8,527)	(104)
Included in OCI	2,438	(9,014)
Purchases	38,173	90,130
Sales	(770)	0
Settlements/ distributions	(14,665)	(4,802)
Closing balance	135,753	119,104
Change in unrealized gain/(losses)	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	141,174	110,431
Transfers into Level 3	0	0
Transfers out of Level 3	(25,510)	0
Included in net income	(7,509)	16,257
Included in OCI	0	0
Purchases	21,077	19,991
Sales	(34,532)	0
Settlements/ distributions	(2,111)	(5,505)
Closing balance	92,589	141,174
Change in unrealized gain/(losses)	(15,591)	16,257
Corporate debt | Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	119,104	42,894
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(8,527)	(104)
Included in OCI	2,438	(9,014)
Purchases	38,173	90,130
Sales	(770)	0
Settlements/ distributions	(14,665)	(4,802)
Closing balance	135,753	119,104
Change in unrealized gain/(losses)	0	0
CLO-Equities | Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	5,016	5,910
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	2,395	2,611
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(2,111)	(3,505)
Closing balance	5,300	5,016
Change in unrealized gain/(losses)	2,395	2,611
Other privately held investments | Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	136,158	104,521
Transfers into Level 3	0	0
Transfers out of Level 3	(25,510)	0
Included in net income	(9,904)	13,646
Included in OCI	0	0
Purchases	21,077	19,991
Sales	(34,532)	0
Settlements/ distributions	0	(2,000)
Closing balance	87,289	136,158
Change in unrealized gain/(losses)	(17,986)	13,646
Derivative instruments
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	5,630
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	0	(3,542)
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	(2,088)
Closing balance	0	0
Change in unrealized gains/(losses)	$ 0	$ 0

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Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

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