FAIR VALUE MEASUREMENTS - Summary of Level 3 Fair Value Measurement Inputs (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value Inputs Assets Quantitative Information [Line Items]
Asset fair value	$ 996,751	$ 947,982
Fixed maturities, available for sale	11,326,894	12,313,200
Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Asset fair value	141,174	110,431
Fixed maturities, available for sale	119,104	$ 42,894
Significant unobservable inputs (Level 3) | Discounted cash flow | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Asset fair value	$ 5,016
Estimated maturity date (years)	5 years
Significant unobservable inputs (Level 3) | Discounted cash flow | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Asset fair value	$ 17,169
Significant unobservable inputs (Level 3) | Discounted cash flow | Minimum | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date (years)	1 year
Significant unobservable inputs (Level 3) | Discounted cash flow | Maximum | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date (years)	3 years
Significant unobservable inputs (Level 3) | Discounted cash flow | Weighted average | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date (years)	5 years
Significant unobservable inputs (Level 3) | Discounted cash flow | Weighted average | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date (years)	2 years
Significant unobservable inputs (Level 3) | Discounted cash flow | Discount rate | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.066
Significant unobservable inputs (Level 3) | Discounted cash flow | Discount rate | Weighted average | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.066
Significant unobservable inputs (Level 3) | Discounted cash flow | Default rate | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.045
Significant unobservable inputs (Level 3) | Discounted cash flow | Default rate | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.005
Significant unobservable inputs (Level 3) | Discounted cash flow | Default rate | Weighted average | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.045
Significant unobservable inputs (Level 3) | Discounted cash flow | Default rate | Weighted average | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.005
Significant unobservable inputs (Level 3) | Discounted cash flow | Loss severity rate | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.500
Significant unobservable inputs (Level 3) | Discounted cash flow | Loss severity rate | Weighted average | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.500
Significant unobservable inputs (Level 3) | Discounted cash flow | Collateral spread | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.030
Significant unobservable inputs (Level 3) | Discounted cash flow | Collateral spread | Weighted average | CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.030
Significant unobservable inputs (Level 3) | Discounted cash flow | Loss absorption yield | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.010
Significant unobservable inputs (Level 3) | Discounted cash flow | Loss absorption yield | Weighted average | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Discounted cash flow	0.010
Significant unobservable inputs (Level 3) | Valuation, Market Approach | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Asset fair value	$ 119,000