Derivative Instruments - Notional Value and Fair Value of Derivative Instruments (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Notional Value	$ 448,584	$ 480,991
Derivative Assets	22,082	15,422
Derivative Liabilities	16,147	16,923
Exchange-traded futures
Derivative [Line Items]
Notional Value	100,466	131,876
Derivative Assets	1,564	392
Derivative Liabilities	1,895	1,186
Currency forwards
Derivative [Line Items]
Notional Value	66,216	66,058
Derivative Assets	7,647	7,344
Derivative Liabilities	7,133	6,980
Interest rate swaps
Derivative [Line Items]
Notional Value	10,683	13,483
Derivative Assets	545	497
Derivative Liabilities	652	833
Credit default swaps
Derivative [Line Items]
Notional Value	159,622	155,757
Derivative Assets	9,572	6,594
Derivative Liabilities	4,883	6,967
Total return swaps
Derivative [Line Items]
Notional Value	61,597	63,817
Derivative Assets	2,754	595
Derivative Liabilities	1,060	527
Option swaps
Derivative [Line Items]
Notional Value	50,000	50,000
Derivative Assets	0	0
Derivative Liabilities	$ 524	$ 430