INVESTMENTS - Repurchase Agreements (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Total	$ 890,017	$ 1,413,068
AFS corporate securities
Schedule of Investments [Line Items]
Total	837,545	1,373,779
Residential mortgage loans
Schedule of Investments [Line Items]
Total	52,472	39,289
Overnight
Schedule of Investments [Line Items]
Total	0	0
Overnight | AFS corporate securities
Schedule of Investments [Line Items]
Total	0	0
Overnight | Residential mortgage loans
Schedule of Investments [Line Items]
Total	0	0
Less than 30 Days
Schedule of Investments [Line Items]
Total	224	39,289
Less than 30 Days | AFS corporate securities
Schedule of Investments [Line Items]
Total	0	0
Less than 30 Days | Residential mortgage loans
Schedule of Investments [Line Items]
Total	224	39,289
30 - 90 Days
Schedule of Investments [Line Items]
Total	862,301	524,411
30 - 90 Days | AFS corporate securities
Schedule of Investments [Line Items]
Total	836,566	524,411
30 - 90 Days | Residential mortgage loans
Schedule of Investments [Line Items]
Total	25,735	0
Greater than 90 Days
Schedule of Investments [Line Items]
Total	27,492	849,368
Greater than 90 Days | AFS corporate securities
Schedule of Investments [Line Items]
Total	979	849,368
Greater than 90 Days | Residential mortgage loans
Schedule of Investments [Line Items]
Total	$ 26,513	$ 0