Guarantees and Off-Balance Sheet Arrangements (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	$ 425,000
Line of credit facility, remaining borrowing capacity	425,000
Pledge Lines
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	250,000
Line of credit facility, remaining borrowing capacity	250,000
BMO Harris Bank | Broker Loan
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	25,000
Line of credit facility, remaining borrowing capacity	25,000
BMO Harris Bank | Tri-Party Pledge Line
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	75,000
Line of credit facility, remaining borrowing capacity	75,000
BMO Harris Bank | Pledge Lines
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	150,000
Line of credit facility, remaining borrowing capacity	150,000
BMO Harris Bank | Spike Line
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	150,000
Line of credit facility, remaining borrowing capacity	150,000
Morgan Stanley | Revolving Credit Facility
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	25,000
Line of credit facility, remaining borrowing capacity	$ 25,000