FAIR VALUE MEASUREMENTS - Changes in Level 3 for Financial Instruments (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($) fund	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	$ 263,905,000	$ 227,716,000	$ 239,453,000	$ 228,342,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(6,899,000)	0	(6,899,000)
Included in net income	2,507,000	(159,000)	7,297,000	735,000
Included in OCI	1,036,000	1,517,000	1,704,000	1,022,000
Purchases	17,386,000	8,239,000	37,050,000	19,709,000
Sales	(19,343,000)	(165,000)	(20,013,000)	(165,000)
Settlements/ distributions	(6,179,000)	(15,454,000)	(6,179,000)	(27,949,000)
Closing balance	259,312,000	214,795,000	259,312,000	214,795,000
Change in unrealized gains/(losses)	$ 2,269,000	$ 354,000	$ 7,059,000	$ 2,082,000
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other comprehensive income (loss)	Other comprehensive income (loss)	Other comprehensive income (loss)	Other comprehensive income (loss)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment income, Net Investment Gain (Loss)	Net investment income, Net Investment Gain (Loss)	Net investment income, Net Investment Gain (Loss)	Net investment income, Net Investment Gain (Loss)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net investment income, Net Investment Gain (Loss)	Net investment income, Net Investment Gain (Loss)	Net investment income, Net Investment Gain (Loss)	Net investment income, Net Investment Gain (Loss)
Transfers out of Level 3 into Level 2	$ 0	$ 0	$ 0	$ 0
Number of investment funds transferred from level 3 to NAV practical expedient | fund		1
Fixed maturities, available for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	166,885,000	$ 126,475,000	147,223,000	135,753,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	238,000	(513,000)	238,000	(1,347,000)
Included in OCI	1,036,000	1,517,000	1,704,000	1,022,000
Purchases	17,386,000	8,239,000	37,050,000	12,471,000
Sales	(19,343,000)	(165,000)	(20,013,000)	(165,000)
Settlements/ distributions	(1,237,000)	(10,544,000)	(1,237,000)	(22,725,000)
Closing balance	164,965,000	125,009,000	164,965,000	125,009,000
Change in unrealized 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	133,742,000	126,475,000	126,391,000	135,753,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	238,000	(513,000)	238,000	(1,347,000)
Included in OCI	687,000	1,517,000	1,044,000	1,022,000
Purchases	17,386,000	8,239,000	25,050,000	12,471,000
Sales	(19,343,000)	(165,000)	(20,013,000)	(165,000)
Settlements/ distributions	(1,237,000)	(10,544,000)	(1,237,000)	(22,725,000)
Closing balance	131,473,000	125,009,000	131,473,000	125,009,000
Change in unrealized gains/(losses)	0	0	0	0
Fixed maturities, available for sale | ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	33,143,000	0	20,832,000	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	0	0	0	0
Included in OCI	349,000	0	660,000	0
Purchases	0	0	12,000,000	0
Sales	0	0	0	0
Settlements/ distributions	0	0	0	0
Closing balance	33,492,000	0	33,492,000	0
Change in unrealized gains/(losses)	0	0	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	97,020,000	101,241,000	92,230,000	92,589,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(6,899,000)	0	(6,899,000)
Included in net income	2,269,000	354,000	7,059,000	2,082,000
Included in OCI	0	0	0	0
Purchases	0	0	0	7,238,000
Sales	0	0	0	0
Settlements/ distributions	(4,942,000)	(4,910,000)	(4,942,000)	(5,224,000)
Closing balance	94,347,000	89,786,000	94,347,000	89,786,000
Change in unrealized gains/(losses)	2,269,000	354,000	7,059,000	2,082,000
Other investments | CLO-Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	4,986,000	0	5,300,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in net income	0	0	0	0
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements/ distributions	0	(488,000)	0	(802,000)
Closing balance	0	4,498,000	0	4,498,000
Change in unrealized gains/(losses)	0	0	0	0
Other investments | Other privately held investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	97,020,000	96,255,000	92,230,000	87,289,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(6,899,000)	0	(6,899,000)
Included in net income	2,269,000	354,000	7,059,000	2,082,000
Included in OCI	0	0	0	0
Purchases	0	0	0	7,238,000
Sales	0	0	0	0
Settlements/ distributions	(4,942,000)	(4,422,000)	(4,942,000)	(4,422,000)
Closing balance	94,347,000	85,288,000	94,347,000	85,288,000
Change in unrealized gains/(losses)	$ 2,269,000	$ 354,000	$ 7,059,000	$ 2,082,000