Loans, Leases and Allowance for Credit Losses - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, unamortized loan fees	$ 120.0	$ 106.0
Financing receivable, unamortized premium	186.0	175.0
Loans Past Due 90 Days or More and Still Accruing	356.0	326.0
Interest income associated with loans on nonaccrual status	36.2	24.5	$ 12.3
Modified loans current with contractual payments	114.0	128.0	95.0
Modified loans on nonaccrual status	89.0	169.0	111.0
Amortized cost basis	203.0	297.0	206.0
Interest receivable	287.0	272.0
Loan sales	773.0	729.0
Net gain (loss) on loan sales	1.5	(6.6)
Charge-offs	0.2	3.4
Financing Receivable, Purchase
Financing Receivable, Allowance for Credit Loss [Line Items]
Loan purchases	2,700.0	1,700.0
Residential - EBO
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans Past Due 90 Days or More and Still Accruing	290.0	326.0
Amortized cost basis	532.0	366.0	225.0
Interest receivable allowance	1.2	1.5
Loan purchases	518.0	385.0
Residential - EBO | Financial Asset, Current to 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Modified amount	27.0	29.0	26.0
Residential - EBO | Over 90 days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Modified amount	$ 123.0	$ 11.0	$ 12.0