Offsetting Assets and Liabilities - Offsetting Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Securities Borrowed [Abstract]
Gross Amounts of Recognized Assets	$ 19,899	$ 7,808
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Assets Presented in the Statement of Financial Condition	19,899	7,808
Financial Instruments Collateral	(18,327)	(7,344)
Cash Collateral Received	0	0
Net Amount	1,572	464
Derivative Asset [Abstract]
Cash Collateral Received	(2,900)	(400)
Derivatives
Derivative Asset [Abstract]
Gross Amounts of Recognized Assets	15,422	21,741
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Assets Presented in the Statement of Financial Condition	15,422	21,741
Financial Instruments Collateral	0	0
Cash Collateral Received	(2,872)	(380)
Net Amount	12,550	21,361
Exchange-traded options | Long exchange-traded options
Derivative Asset [Abstract]
Gross Amounts of Recognized Assets	1,893	7,527
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Assets Presented in the Statement of Financial Condition	1,893	7,527
Financial Instruments Collateral	0	0
Cash Collateral Received	0	0
Net Amount	$ 1,893	$ 7,527