Loans (Summary of Loan Portfolio) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Loans [Line Items]
Total loans, net of unearned income	$ 39,196,485	$ 34,789,104
Total loans, net of unearned income, percentage	100.00%	100.00%
Commercial
Loans [Line Items]
Total loans, net of unearned income	$ 12,549,164	$ 11,904,068
Total loans, net of unearned income, percentage	32.00%	34.00%
Commercial real estate
Loans [Line Items]
Total loans, net of unearned income	$ 9,950,947	$ 8,990,286
Total loans, net of unearned income, percentage	25.00%	26.00%
Home equity
Loans [Line Items]
Total loans, net of unearned income	$ 332,698	$ 335,155
Total loans, net of unearned income, percentage	1.00%	1.00%
Residential real estate
Loans [Line Items]
Total loans, net of unearned income	$ 2,372,383	$ 1,637,099
Total loans, net of unearned income, percentage	6.00%	5.00%
Premium finance receivables | Property & casualty
Loans [Line Items]
Total loans, net of unearned income	$ 5,849,459	$ 4,855,487
Total loans, net of unearned income, percentage	15.00%	14.00%
Premium finance receivables | Life insurance
Loans [Line Items]
Total loans, net of unearned income	$ 8,090,998	$ 7,042,810
Total loans, net of unearned income, percentage	21.00%	20.00%
Consumer and other
Loans [Line Items]
Total loans, net of unearned income	$ 50,836	$ 24,199
Total loans, net of unearned income, percentage	0.00%	0.00%