Debt Securities Available-for-Sale - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) security loan	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) security loan	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, restricted	$ 613,300,000		$ 613,300,000		$ 420,400,000
Proceeds from sale of debt securities available-for-sale	0	$ 0	0	$ 0
Debt securities, available-for-sale, realized gain (loss)	0		0	1,000
Debt securities, available-for-sale, realized gain		0
Debt securities, available-for-sale, realized loss		7,000		7,000
Debt securities, trading, realized (loss) gain	804,000	$ 710,000	1,500,000	$ 1,600,000
Debt securities available-for-sale, allowance for credit loss	0		0		0
Accrued interest receivable associated with debt securities available-for-sale	$ 3,800,000		$ 3,800,000		$ 3,100,000
Debt securities, available-for-sale, accrued interest, after allowance for credit loss, statement of financial position [extensible enumeration]	Accrued interest receivable		Accrued interest receivable		Accrued interest receivable
GSE
Debt Securities, Available-for-sale [Line Items]
Number of debt securities, unrealized loss position longer than 12 months | loan	1		1
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Number of debt securities, unrealized loss position longer than 12 months | loan	3		3
Pass Through | GSE
Debt Securities, Available-for-sale [Line Items]
Number of debt securities | security	106		106
Number of debt securities, unrealized loss position less than 12 months | security	1		1
Non Pass Through | Real estate mortgage investment conduits (REMICs)
Debt Securities, Available-for-sale [Line Items]
Number of debt securities, unrealized loss position longer than 12 months | loan	66		66
Number of debt securities, unrealized loss position less than 12 months | loan	5		5