Debt Securities Available-for-Sale - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) loan security	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) loan security	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, restricted	$ 567,700,000		$ 567,700,000		$ 591,700,000
Proceeds from sale of debt securities available-for-sale	0	$ 0	0	$ 41,464,000
Debt securities, available-for-sale, realized gain (loss)	0	0
Debt securities, available-for-sale, realized gain			22,000	264,000
Debt securities, available-for-sale, realized loss			39,000	0
Debt securities, trading, realized gain (loss)	(295,000)	$ 426,000	723,000	$ 2,800,000
Debt securities available-for-sale, allowance for credit loss	0		0		0
Accrued interest receivable associated with debt securities available-for-sale	$ 1,900,000		$ 1,900,000		$ 2,800,000
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued interest receivable		Accrued interest receivable
GSE
Debt Securities, Available-for-sale [Line Items]
Number of debt securities, unrealized loss position longer than 12 months | loan	5		5
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Number of debt securities, unrealized loss position longer than 12 months | loan	18		18
Number of debt securities, unrealized loss position less than 12 months | security	1		1
Pass Through | GSE
Debt Securities, Available-for-sale [Line Items]
Number of debt securities | security	114		114
Number of debt securities, unrealized loss position less than 12 months | security	11		11
Non Pass Through | GSE
Debt Securities, Available-for-sale [Line Items]
Number of debt securities, unrealized loss position longer than 12 months | loan	77		77