FHLB Advances, Other Borrowings and Subordinated Notes - Narrative (Details) $ in Millions		5 Months Ended	9 Months Ended
	May 31, 2023 CAD ($)	May 30, 2023	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 12, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 18, 2018 USD ($)
Debt Instrument [Line Items]
Credit agreement balances			$ 178,411,000	$ 199,793,000		$ 64,268,000
Secured borrowings			391,681,000	317,942,000		311,958,000
Collateral Pledged
Debt Instrument [Line Items]
Pledged financial instruments			16,400,000
Securities sold under repurchase agreements | Overnight Sweep Collateral
Debt Instrument [Line Items]
Securities sold under agreements to repurchase			14,183,000	17,600,000		9,200,000
Secured Debt
Debt Instrument [Line Items]
Secured borrowings			8,900,000
Term Loan Facility
Debt Instrument [Line Items]
Credit agreement balances					$ 200,000,000		$ 150,000,000
Amount outstanding			178,400,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit agreement balances							$ 100,000,000
Amount outstanding			0
Receivables Purchase Agreement | Secured Debt
Debt Instrument [Line Items]
Borrowing capacity	$ 520
Borrowing fee rate	0.825%	0.775%
Secured borrowings			$ 382,800,000	$ 309,700,000		$ 303,500,000
Receivables Purchase Agreement | Secured Debt | Canadian Commercial Paper Rate
Debt Instrument [Line Items]
Basis spread on variable rate			0.825%