Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest income:
Interest and fees on loans	$ 120.9	$ 96.5	$ 232.3	$ 188.2
Interest and dividends on investment securities:
Taxable	15.7	13.9	30.8	27.1
Exempt from federal taxes	0.5	0.6	1.0	1.2
Interest on deposits in banks	5.0	2.0	8.6	4.1
Total interest income	142.1	113.0	272.7	220.6
Interest expense:
Interest on deposits	14.1	7.2	26.2	13.4
Interest on securities sold under repurchase agreements	1.1	0.7	2.1	1.1
Interest on other borrowed funds	0.0	0.0	0.0	0.1
Interest on other debt	0.4	0.3	0.7	0.5
Interest on subordinated debentures held by subsidiary trusts	1.2	1.0	2.4	1.9
Total interest expense	16.8	9.2	31.4	17.0
Net interest income	125.3	103.8	241.3	203.6
Provision for loan losses	3.8	2.9	7.5	5.0
Net interest income after provision for loan losses	121.5	100.9	233.8	198.6
Non-interest income:
Mortgage banking revenues	8.4	7.2	13.8	12.6
Investment securities gains (losses), net	0.0	0.0	0.0	0.0
Other income	5.1	2.6	9.4	6.5
Total non-interest income	39.4	37.6	73.9	72.8
Non-interest expense:
Salaries and wages	40.4	34.3	76.5	68.9
Employee benefits	14.0	12.3	28.4	23.6
Outsourced technology services	8.1	7.1	16.0	14.1
Occupancy, net	7.1	6.0	14.1	12.3
Furniture and equipment	3.4	2.9	6.9	6.0
OREO expense, net of income	0.2	(0.1)	0.3	0.1
Professional fees	2.3	2.1	4.2	3.3
FDIC insurance premiums	1.6	1.4	3.1	2.9
Mortgage servicing rights amortization	1.0	0.7	1.9	1.5
Core deposit intangibles amortization	3.0	1.7	5.3	3.5
Other expenses	17.5	16.5	33.4	32.3
Acquisition related expenses	13.5	0.0	15.8	2.3
Total non-interest expense	112.1	84.9	205.9	170.8
Income before income tax expense	48.8	53.6	101.8	100.6
Income tax expense	10.9	11.9	22.3	22.2
Net income	$ 37.9	$ 41.7	$ 79.5	$ 78.4
Earnings per common share, basic (in dollars per share)	$ 0.59	$ 0.74	$ 1.27	$ 1.39
Earnings per common share, diluted (in dollars per share)	$ 0.59	$ 0.74	$ 1.27	$ 1.38
Weighted average common shares outstanding, basic (in shares)	64,504,546	56,335,186	62,419,442	56,288,453
Weighted average common shares outstanding, diluted (in shares)	64,707,459	56,699,021	62,668,391	56,670,400
Payment services revenues
Non-interest income:
Services revenues	$ 10.5	$ 12.9	$ 19.9	$ 23.4
Wealth management revenues
Non-interest income:
Wealth management revenues	5.8	5.8	11.9	11.7
Service charges on deposit accounts
Non-interest income:
Services revenues	5.4	5.3	10.4	10.9
Other service charges, commissions and fees
Non-interest income:
Services revenues	$ 4.2	$ 3.8	$ 8.5	$ 7.7