FAIR VALUE MEASUREMENTS - Changes in Level 3 for Financial Instruments (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||
| Opening balance | $ 403,561,000 | $ 263,905,000 | $ 352,553,000 | $ 239,453,000 |
| Transfers into Level 3 | 1,378,000 | 0 | 1,378,000 | 0 |
| Transfers out of Level 3 | 0 | 0 | (2,572,000) | 0 |
| Included in net income | 3,656,000 | 2,507,000 | 4,013,000 | 7,297,000 |
| Included in OCI | 262,000 | 1,036,000 | (637,000) | 1,704,000 |
| Purchases | 26,434,000 | 17,386,000 | 98,057,000 | 37,050,000 |
| Sales | (1,566,000) | (19,343,000) | (9,250,000) | (20,013,000) |
| Settlements/ distributions | (8,954,000) | (6,179,000) | (18,771,000) | (6,179,000) |
| Closing balance | 424,771,000 | 259,312,000 | 424,771,000 | 259,312,000 |
| Change in unrealized gains/(losses) | $ 3,335,000 | $ 2,269,000 | $ 3,549,000 | $ 7,059,000 |
| 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) |
| Fixed maturities, available for sale | ||||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||
| Opening balance | $ 279,422,000 | $ 166,885,000 | $ 228,628,000 | $ 147,223,000 |
| Transfers into Level 3 | 1,378,000 | 0 | 1,378,000 | 0 |
| Transfers out of Level 3 | 0 | 0 | (2,572,000) | 0 |
| Included in net income | 321,000 | 238,000 | 464,000 | 238,000 |
| Included in OCI | 262,000 | 1,036,000 | (637,000) | 1,704,000 |
| Purchases | 22,684,000 | 17,386,000 | 94,307,000 | 37,050,000 |
| Sales | (1,566,000) | (19,343,000) | (9,250,000) | (20,013,000) |
| Settlements/ distributions | (8,954,000) | (1,237,000) | (18,771,000) | (1,237,000) |
| Closing balance | 293,547,000 | 164,965,000 | 293,547,000 | 164,965,000 |
| 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 | 225,010,000 | 133,742,000 | 189,272,000 | 126,391,000 |
| Transfers into Level 3 | 1,378,000 | 0 | 1,378,000 | 0 |
| Transfers out of Level 3 | 0 | 0 | (2,572,000) | 0 |
| Included in net income | 318,000 | 238,000 | 460,000 | 238,000 |
| Included in OCI | 1,468,000 | 687,000 | 409,000 | 1,044,000 |
| Purchases | 4,834,000 | 17,386,000 | 60,948,000 | 25,050,000 |
| Sales | (1,566,000) | (19,343,000) | (9,236,000) | (20,013,000) |
| Settlements/ distributions | (7,912,000) | (1,237,000) | (17,129,000) | (1,237,000) |
| Closing balance | 223,530,000 | 131,473,000 | 223,530,000 | 131,473,000 |
| 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 | 54,412,000 | 33,143,000 | 39,356,000 | 20,832,000 |
| Transfers into Level 3 | 0 | 0 | 0 | 0 |
| Transfers out of Level 3 | 0 | 0 | 0 | 0 |
| Included in net income | 3,000 | 0 | 4,000 | 0 |
| Included in OCI | (1,206,000) | 349,000 | (1,046,000) | 660,000 |
| Purchases | 17,850,000 | 0 | 33,359,000 | 12,000,000 |
| Sales | 0 | 0 | (14,000) | 0 |
| Settlements/ distributions | (1,042,000) | 0 | (1,642,000) | 0 |
| Closing balance | 70,017,000 | 33,492,000 | 70,017,000 | 33,492,000 |
| 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 | 124,139,000 | 97,020,000 | 123,925,000 | 92,230,000 |
| Transfers into Level 3 | 0 | 0 | 0 | 0 |
| Transfers out of Level 3 | 0 | 0 | 0 | 0 |
| Included in net income | 3,335,000 | 2,269,000 | 3,549,000 | 7,059,000 |
| Included in OCI | 0 | 0 | 0 | 0 |
| Purchases | 3,750,000 | 0 | 3,750,000 | 0 |
| Sales | 0 | 0 | 0 | 0 |
| Settlements/ distributions | 0 | (4,942,000) | 0 | (4,942,000) |
| Closing balance | 131,224,000 | 94,347,000 | 131,224,000 | 94,347,000 |
| Change in unrealized gains/(losses) | 3,335,000 | 2,269,000 | 3,549,000 | 7,059,000 |
| Other investments | Other privately held investments | ||||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||
| Opening balance | 124,139,000 | 97,020,000 | 123,925,000 | 92,230,000 |
| Transfers into Level 3 | 0 | 0 | 0 | 0 |
| Transfers out of Level 3 | 0 | 0 | 0 | 0 |
| Included in net income | 3,335,000 | 2,269,000 | 3,549,000 | 7,059,000 |
| Included in OCI | 0 | 0 | 0 | 0 |
| Purchases | 3,750,000 | 0 | 3,750,000 | 0 |
| Sales | 0 | 0 | 0 | 0 |
| Settlements/ distributions | 0 | (4,942,000) | 0 | (4,942,000) |
| Closing balance | 131,224,000 | 94,347,000 | 131,224,000 | 94,347,000 |
| Change in unrealized gains/(losses) | $ 3,335,000 | $ 2,269,000 | $ 3,549,000 | $ 7,059,000 |