Derivative Instruments - Schedule of Gains and Losses for Derivative Instruments Recognized in Investment Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative [Line Items]
Gains (losses) on derivative instruments	$ (15,285)	$ 8,936	$ (21,865)	$ (2,419)
Exchange-traded futures
Derivative [Line Items]
Gains (losses) on derivative instruments	(5,443)	4,622	(7,893)	2,022
Currency forwards
Derivative [Line Items]
Gains (losses) on derivative instruments	(460)	594	(105)	557
Interest rate swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	(1,298)	93	(873)	144
Credit default swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	(920)	(272)	(1,840)	(4,513)
Total return swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	(5,295)	2,858	(9,233)	(843)
Option swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	$ (1,869)	$ 1,041	$ (1,921)	$ 214