Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Assets
Cash and due from banks	$ 371.5	$ 349.2
Interest bearing deposits in banks	219.5	521.2
Federal funds sold	2.1	0.1
Total cash and cash equivalents	593.1	870.5
Investment securities:
Available-for-sale, net of allowance for credit losses of $0 at September 30, 2023 and December 31, 2022 (amortized cost of $6,290.2 at September 30, 2023 and $7,573.5 at December 31, 2022)	5,627.7	6,946.1
Held-to-maturity, net of allowance for credit losses of $0.8 at September 30, 2023 and $1.9 at December 31, 2022 (estimated fair values of $2,796.1 at September 30, 2023 and $3,052.2 at December 31, 2022)	3,259.5	3,451.8
Total investment securities	8,887.2	10,397.9
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	189.5	198.6
Loans held for sale	59.1	79.9
Loans held for investment, net of deferred fees and costs	18,213.3	18,099.2
Allowance for credit losses	(226.7)	(220.1)
Net loans held for investment	17,986.6	17,879.1
Goodwill	1,100.9	1,100.9
Bank Owned Life Insurance	500.8	497.9
Premises and equipment, net of accumulated depreciation	446.3	444.7
Other intangibles, net of accumulated amortization	85.2	97.0
Accrued interest receivable	129.2	118.3
Mortgage servicing rights, net of accumulated amortization and impairment reserve	29.1	31.1
Real Estate Acquired Through Foreclosure	11.6	12.7
Deferred tax assets	215.3	210.5
Other assets	306.9	348.7
Total assets	30,540.8	32,287.8
Deposits:
Non-interest bearing	6,402.6	7,560.0
Interest bearing	17,276.9	17,513.6
Total deposits	23,679.5	25,073.6
Securities sold under repurchase agreements	889.5	1,052.9
Accounts payable and accrued expenses	452.9	445.9
Accrued interest payable	63.7	14.5
Long-term debt	120.8	120.8
Other Short-term Borrowings	2,067.0	2,327.0
Allowance for credit losses on off-balance sheet credit exposures	18.8	16.2
Subordinated debentures held by subsidiary trusts	163.1	163.1
Total liabilities	27,455.3	29,214.0
Stockholders’ equity:
Preferred stock, no par value; 100,000 shares authorized; none issued and outstanding	0.0	0.0
Common stock and additional paid-in-capital, $0.00001 par value; 150,000,000 shares authorized; 105,011,371 and 104,442,023 shares were issued and outstanding at September 30, 2023 and December 31, 2022	2,484.9	2,478.2
Retained earnings	1,122.3	1,072.7
Accumulated other comprehensive loss, net	(521.7)	(477.1)
Total stockholders’ equity	3,085.5	3,073.8
Total liabilities and stockholders’ equity	$ 30,540.8	$ 32,287.8
Common Stock, Shares Authorized	150,000,000	150,000,000