Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest income:
Interest and fees on loans	$ 790.2	$ 430.2	$ 453.4
Interest and dividends on investment securities:
Taxable	212.4	67.1	63.4
Exempt from federal taxes	5.4	5.6	2.7
Interest on deposits in banks	8.7	2.6	4.1
Total interest income	1,021.5	506.5	524.4
Interest expense:
Interest on deposits	48.3	8.1	18.1
Interest on securities sold under repurchase agreements	2.5	0.4	0.9
Interest on other borrowed funds	15.3	0.0	0.0
Interest on long-term debt	6.0	6.0	4.6
Interest on subordinated debentures held by subsidiary trusts	6.8	2.8	3.0
Total interest expense	78.9	17.3	26.6
Net interest income	942.6	489.2	497.8
Provision for (reversal of) credit losses	82.7	(14.6)	56.9
Net interest income after provision for (reversal of) credit losses	859.9	503.8	440.9
Payment Services Revenues	74.1	45.1	41.1
Non-interest income:
Revenue from Contract with Customer, Excluding Assessed Tax	15.5	7.9	12.1
Fees and Commissions, Mortgage Banking and Servicing	18.7	40.8	47.3
Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions	34.3	26.3	23.8
Service Charges on Deposit Accounts	24.6	16.5	17.6
Investment securities (losses) gains, net	(24.4)	1.1	0.3
Other income	20.4	11.8	13.7
Total non-interest income	163.2	149.5	155.9
Non-interest expense:
Salaries and wages	282.1	164.9	173.7
Employee benefits	77.5	55.8	49.4
Information Technology and Data Processing	54.3	32.8	32.8
Occupancy, Net	44.0	28.7	28.5
Equipment Expense	23.4	17.6	15.5
OREO expense, net of income	2.3	(0.2)	(0.5)
Professional fees	19.1	12.1	10.9
FDIC insurance premiums	14.0	6.6	5.9
Other intangibles amortization	15.9	9.9	10.9
Other expenses	114.5	65.7	60.4
Acquisition related expenses	118.9	11.6	0.0
Total non-interest expense	766.0	405.5	387.5
Income before income tax	257.1	247.8	209.3
Provision for income tax	54.9	55.7	48.1
Net income	$ 202.2	$ 192.1	$ 161.2
Basic earnings per common share (in dollars per share)	$ 1.96	$ 3.12	$ 2.53
Diluted earnings per common share (in dollars per share)	$ 1.96	$ 3.11	$ 2.53
Other Interest and Dividend Income	$ 4.8	$ 1.0	$ 0.8