Other Borrowings and Subordinated Notes and Debentures - Narrative (Details) - USD ($)	1 Months Ended
	Sep. 30, 2025	Mar. 31, 2026	Dec. 31, 2025
Debt Instrument [Line Items]
Advances from FHLB		$ 431,600,000	$ 286,600,000
Mortgage loans and investment securities securing FHLB advances		7,260,000,000
Additional advances from FHLB		$ 5,830,000,000
Subordinated notes
Debt Instrument [Line Items]
Face amount of debt	$ 325,000,000.0
Fixed rate (as percent)	6.25%
Offering price, percent	100.00%
Debt issuance costs incurred	$ 3,900,000
Floating rate (as percent)	3.02%