Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest income:
Interest and fees on loans	$ 112.3	$ 120.0	$ 336.4	$ 352.3
Interest and dividends on investment securities:
Taxable	15.5	15.1	48.4	45.9
Exempt from federal taxes	0.6	0.5	1.6	1.5
Interest on deposits in banks	0.5	5.7	3.5	14.3
Total interest income	128.9	141.3	389.9	414.0
Interest expense:
Interest on deposits	3.4	13.4	15.2	39.6
Interest on securities sold under repurchase agreements	0.1	1.0	0.7	3.1
Interest on other debt	1.7	0.3	3.0	1.0
Interest on subordinated debentures held by subsidiary trusts	0.7	1.1	2.4	3.5
Total interest expense	5.9	15.8	21.3	47.2
Net interest income	123.0	125.5	368.6	366.8
Provision for credit losses	5.2	2.6	53.7	10.1
Net interest income after provision for credit losses	117.8	122.9	314.9	356.7
Non-interest income:
Mortgage banking revenues	14.3	10.4	39.4	24.6
Investment securities gains (losses), net	0.1	0.1	0.1	0.1
Other income	4.6	4.0	12.5	13.4
Total non-interest income	44.7	38.2	122.8	107.5
Non-interest expense:
Salaries and wages	46.0	40.1	130.1	115.3
Employee benefits	11.8	11.9	36.4	40.3
Outsourced technology services	8.4	7.9	24.5	23.9
Occupancy, net	7.2	7.1	21.3	21.2
Furniture and equipment	4.1	3.3	11.1	10.2
OREO expense, net of income	0.0	(0.8)	(0.4)	(0.5)
Professional fees	2.9	3.5	8.6	9.3
FDIC insurance premiums	1.3	0.4	4.5	3.5
Mortgage servicing rights impairment			9.9	0.0
Core deposit intangibles amortization	2.7	3.0	8.3	8.3
Other expenses	15.1	16.5	45.7	46.9
Acquisition related expenses	0.0	3.8	0.0	19.6
Noninterest Expense	99.5	96.7	290.1	298.0
Income before income tax expense	63.0	64.4	147.6	166.2
Income tax expense	14.7	15.3	33.3	37.6
Net income	$ 48.3	$ 49.1	$ 114.3	$ 128.6
Earnings per common share, basic (in dollars per share)	$ 0.76	$ 0.76	$ 1.78	$ 2.03
Earnings per common share, diluted (in dollars per share)	$ 0.76	$ 0.76	$ 1.78	$ 2.03
Weighted average common shares outstanding, basic (in shares)	63,764,474	64,832,324	64,184,832	63,232,575
Weighted average common shares outstanding, diluted (in shares)	63,861,457	65,043,486	64,295,525	63,471,283
Payment services revenues
Non-interest income:
Non-interest income	$ 10.5	$ 10.8	$ 30.0	$ 30.7
Wealth management revenues
Non-interest income:
Wealth management revenues	5.9	5.9	17.5	17.8
Service charges on deposit accounts
Non-interest income:
Non-interest income	4.3	5.3	13.3	15.7
Other service charges, commissions and fees
Non-interest income:
Non-interest income	$ 5.0	$ 1.7	$ 10.0	$ 5.2