Derivative Instruments - Schedule of Gains and Losses for Derivative Instruments Recognized in Investment Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Derivative [Line Items]
Net (losses) on derivative instruments	$ (11,074)	$ (1,630)	$ (23,850)	$ (6,580)
Exchange-traded futures
Derivative [Line Items]
Net (losses) on derivative instruments	(3,891)	(871)	(3,633)	(2,450)
Currency forwards
Derivative [Line Items]
Net (losses) on derivative instruments	(5,120)	(9)	(5,775)	355
Interest rate swaps
Derivative [Line Items]
Net (losses) on derivative instruments	42	282	(310)	425
Credit default swaps
Derivative [Line Items]
Net (losses) on derivative instruments	(2,921)	(91)	(2,487)	(920)
Total return swaps
Derivative [Line Items]
Net (losses) on derivative instruments	2,040	(682)	(9,377)	(3,938)
Option swaps
Derivative [Line Items]
Net (losses) on derivative instruments	$ (1,224)	$ (259)	$ (2,268)	$ (52)