Derivative Instruments - Schedule of Gains and Losses for Derivative Instruments Recognized in Investment Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Gains (losses) on derivative instruments	$ (4,950)	$ (10,494)
Exchange-traded futures
Derivative [Line Items]
Gains (losses) on derivative instruments	(1,579)	(4,632)
Currency forwards
Derivative [Line Items]
Gains (losses) on derivative instruments	364	(105)
Interest rate swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	143	(63)
Credit default swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	(829)	(2,228)
Total return swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	(3,256)	(2,056)
Option swaps
Derivative [Line Items]
Gains (losses) on derivative instruments	$ 207	$ (1,410)