First Interstate BancSystem (FIBK) 10-K 29 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Jan. 31, 2024	Jun. 30, 2023
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-34653
Entity Registrant Name	FIRST INTERSTATE BANCSYSTEM, INC.
Entity Central Index Key	0000860413
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-0331430
Entity Address, Address Line One	401 North 31st Street
Entity Address, City or Town	Billings,
Entity Address, State or Province	MT
Entity Address, Postal Zip Code	59101
City Area Code	406
Local Phone Number	255-5311
Title of 12(b) Security	Common stock, $0.00001 par value
Trading Symbol	FIBK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2,100,000,000
Entity Common Stock, Shares Outstanding		103,935,844
Document Financial Statement Error Correction [Flag]	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Auditor Information [Abstract]
Auditor Name	RSM US LLP
Auditor Location	Des Moines, Iowa
Auditor Firm ID	49

Cover

Cover	12 Months Ended
	Dec. 31, 2023
Cover [Abstract]
Documents Incorporated by Reference	The registrant intends to file a definitive Proxy Statement for the Annual Meeting of Shareholders scheduled to be held May 22, 2024. The information required by Part III of this Form 10-K is incorporated by reference to such Proxy Statement.

Earnings per Common Share - Tab

Earnings per Common Share - Tables	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings per Share	The following table sets forth the computation of basic and diluted earnings per share for the periods presented: Year Ended December 31, 2023 2022 2021 Net income $ 257.5 $ 202.2 $ 192.1 Weighted average common shares outstanding for basic earnings per share computation 103,752,206 103,274,070 61,650,312 Dilutive effects of stock-based compensation 27,897 66,929 91,516 Weighted average common shares outstanding for diluted earnings per common share computation 103,780,103 103,340,999 61,741,828 Basic earnings per common share $ 2.48 $ 1.96 $ 3.12 Diluted earnings per common share 2.48 1.96 3.11 Anti-dilutive unvested time restricted stock 119,144 52,027 83,952

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets
Cash and due from banks	$ 378.2	$ 349.2
Federal funds sold	199.7	521.2
Interest bearing deposits in banks	0.1	0.1
Total cash and cash equivalents	578	870.5
Investment securities:
Available-for-sale	5,841.5	6,946.1
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	3,207.9	3,451.8
Investments, Total	9,049.4	10,397.9
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	223.2	198.6
Loans Held for Sale (Table)	47.4	79.9
Loans and Leases Receivable, Net of Deferred Income	18,279.6	18,099.2
Less allowance for loan losses	(227.7)	(220.1)
Net loans	18,051.9	17,879.1
Goodwill	1,100.9	1,100.9
Company-owned life insurance	502.4	497.9
Premises and equipment, net of accumulated depreciation	444.3	444.7
Other intangibles, net of accumulated amortization	81.4	97
Accrued interest receivable	129.1	118.3
Mortgage servicing rights, net of accumulated amortization and impairment reserve	28.3	31.1
Other real estate owned	16.5	12.7
Deferred Income Tax Assets, Net	150	210.5
Other assets	268.4	348.7
Total assets	30,671.2	32,287.8
Deposits:
Non-interest bearing	6,029.6	7,560
Interest bearing	17,293.5	17,513.6
Total deposits	23,323.1	25,073.6
Securities sold under repurchase agreements	782.7	1,052.9
Accounts payable and accrued expenses	380.4	445.9
Accrued interest payable	52.2	14.5
Long-term debt	120.8	120.8
Other borrowings	2,603	2,327
Allowance for credit losses on off-balance sheet credit exposures	18.4	16.2
Subordinated debentures held by subsidiary trusts	163.1	163.1
Total liabilities	$ 27,443.7	$ 29,214
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Preferred Stock, No Par Value	$ 0	$ 0
Preferred Stock, Shares Authorized	100,000	100,000
Common Stock, Shares, Issued	103,941,626	104,442,023
Common stock, shares, outstanding	103,941,626	104,442,023
Common Stock, Par or Stated Value Per Share	$ 0.00001	$ 0.00001
Stockholders’ equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued or outstanding as of December 31, 2019 and 2018	$ 0	$ 0
Common stock	2,448.9	2,478.2
Retained earnings	1,135.1	1,072.7
Accumulated other comprehensive income (loss), net	(356.5)	(477.1)
Total stockholders’ equity	3,227.5	3,073.8
Total liabilities and stockholders’ equity	$ 30,671.2	$ 32,287.8
Common stock, shares authorized	150,000,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets:
Held-to-maturity investment securities, estimated fair value	$ 2,874	$ 3,052.2

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Interest income:
Interest and fees on loans	$ 979.7	$ 790.2	$ 430.2
Interest and dividends on investment securities:
Taxable	269.1	213.9	68.6
Exempt from federal taxes	3.2	3.9	4.1
Interest on deposits in banks	15.7	8.7	2.6
Total interest income	1,280.1	1,021.5	506.5
Interest expense:
Interest on deposits	242.6	48.3	8.1
Interest on securities sold under repurchase agreements	6.4	2.5	0.4
Interest on other borrowed funds	133.8	15.3	0
Interest on long-term debt	5.8	6	6
Interest on subordinated debentures held by subsidiary trusts	12.7	6.8	2.8
Total interest expense	401.3	78.9	17.3
Net interest income	878.8	942.6	489.2
Provision for (reversal of) credit losses	32.2	82.7	(14.6)
Net interest income after provision for (reversal of) credit losses	846.6	859.9	503.8
Payment Services Revenues	76.4	74.1	45.1
Non-interest income:
Revenue from Contract with Customer, Excluding Assessed Tax	9.5	15.5	7.9
Fees and Commissions, Mortgage Banking and Servicing	8.4	18.7	40.8
Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions	35.3	34.3	26.3
Service Charges on Deposit Accounts	23	24.6	16.5
Investment securities (losses) gains, net	(23.5)	(24.4)	1.1
Other income	17.9	20.4	11.8
Total non-interest income	147	163.2	149.5
Non-interest expense:
Salaries and wages	263.1	282.1	164.9
Employee benefits	75.3	77.5	55.8
Information Technology and Data Processing	59	54.3	32.8
Occupancy, Net	48	44	28.7
Equipment Expense	22.1	23.4	17.6
OREO expense, net of income	1.5	2.3	(0.2)
Professional fees	19.1	19.1	12.1
FDIC insurance premiums	31.5	14	6.6
Other intangibles amortization	15.7	15.9	9.9
Other expenses	121.5	114.5	65.7
Acquisition related expenses	0	118.9	11.6
Total non-interest expense	656.8	766	405.5
Income before income tax	336.8	257.1	247.8
Provision for income tax	79.3	54.9	55.7
Net income	$ 257.5	$ 202.2	$ 192.1
Basic earnings per common share (in dollars per share)	$ 2.48	$ 1.96	$ 3.12
Diluted earnings per common share (in dollars per share)	$ 2.48	$ 1.96	$ 3.11
Other Interest and Dividend Income	$ 12.4	$ 4.8	$ 1

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 257.5	$ 202.2	$ 192.1
Investment securities available-for-sale:
Change in net unrealized gains (losses) during the period	144.8	(613.1)	(113.7)
Reclassification adjustment for net losses (gains) included in income	23.5	24.4	(1.1)
Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale	(7.2)	0.2	0
OCI, Debt Securities, Available-for-Sale, Transfer To Held-to-Maturity, Gain (Loss), before Adjustment and Tax	(1.3)	(26.1)	20.2
Change in net unrealized loss (gain) on derivatives	0.9	(6.7)	4.2
Defined benefit post-retirement benefit plans:
Other comprehensive income (loss), before tax	160.7	(621.3)	(90.4)
Deferred tax (expense) benefit related to other comprehensive income (loss)	(40.1)	155.2	22.8
Other comprehensive income (loss), net of tax	120.6	(466.1)	(67.6)
Comprehensive income (loss), net of tax	$ 378.1	$ (263.9)	$ 124.5

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity Attributable to Parent	$ 1,959.8	$ 941.1	$ 962.1	$ 56.6
Net income	192.1	0	192.1	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (67.6)	0	0	(67.6)
Stock Repurchased and Retired During Period, Shares	128,171
Common shares purchased and retired	$ (5.4)	(5.4)	0	0
Stock issued during period, new issues (in shares)	19,081
Stock issued during period, RSU (in shares)	241,307
Stock Issued During Period, Value, New Issues	$ 0	0	0	0
Non-vested common shares forfeited or canceled	0	0	0	0
Stock compensation expense	0.4	0.4	0	0
Stock compensation expense	8.9	8.9	0	0
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (101.6)	0	(101.6)	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	73,044
Dividends declared (in usd per share)	$ 1.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	45,484
Shares tendered in payment of option price and income tax withholding amounts, shares	6,982
Stockholders' Equity Attributable to Parent	$ 1,986.6	945	1,052.6	(11)
Common Stock, Value, Issued	0	0	0	0
Net income	202.2	0	202.2	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (466.1)	0	0	(466.1)
Stock Repurchased and Retired During Period, Shares	5,040,896
Common shares purchased and retired	$ (199)	(199)	0	0
Stock issued during period, new issues (in shares)	46,913,370
Stock issued during period, RSU (in shares)	458,177
Stock Issued During Period, Value, New Issues	$ 1,722.5	1,722.5	0	0
Non-vested common shares forfeited or canceled	0	0	0	0
Stock compensation expense	0.1	0.1	0	0
Stock compensation expense	9.6	9.6	0	0
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (182.1)	0	(182.1)	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	106,891
Dividends declared (in usd per share)	$ 1.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	17,807
Shares tendered in payment of option price and income tax withholding amounts, shares	4,877
Stockholders' Equity Attributable to Parent	$ 3,073.8	2,478.2	1,072.7	(477.1)
Common Stock, Value, Issued	0	0	0	0
Net income	257.5	0	257.5	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 120.6	0	0	120.6
Stock Repurchased and Retired During Period, Shares	1,056,191
Common shares purchased and retired	$ (34)	(34)	0	0
Stock issued during period, RSU (in shares)	683,574
Non-vested common shares forfeited or canceled	$ 0	0	0	0
Stock compensation expense	4.7	4.7	0	0
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (195.1)	0	(195.1)	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	127,780
Dividends declared (in usd per share)	$ 1.88
Stockholders' Equity Attributable to Parent	$ 3,227.5	2,448.9	1,135.1	(356.5)
Common Stock, Value, Issued	$ 0	$ 0	$ 0	$ 0

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Stockholders' Equity [Abstract]
Stock Repurchased and Retired During Period, Shares	1,056,191	5,040,896	128,171
Stock issued during period, new issues (in shares)		46,913,370	19,081
Stock issued during period, RSU (in shares)	683,574	458,177	241,307
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	127,780	106,891	73,044
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		17,807	45,484
Shares tendered in payment of option price and income tax withholding amounts, shares		4,877	6,982
Dividends declared (in usd per share)	$ 1.88	$ 1.70	$ 1.64

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 257.5	$ 202.2	$ 192.1
Adjustments to reconcile net income from operations to net cash provided by operating activities:
Provision for (reversal of) credit losses	32.2	82.7	(14.6)
Net (gain) loss on disposal of premises and equipment	0.7	(2)	(1.8)
Depreciation and amortization	53.8	55.5	44.4
Net premium amortization on investment securities	2.4	17	38.8
Net loss (gain) on investment securities transactions	23.5	24.4	(1.1)
Realized and unrealized net gains on mortgage banking activities	(2.8)	(9.4)	(26.2)
Net gain on sale of OREO	(0.1)	(0.7)	(0.3)
Write-downs of OREO and other assets pending disposal	1.1	2.8	0
Gain (Loss) on Extinguishment of Debt	0	(1.4)	0
Mortgage servicing rights impairment (recovery)	0	(3.4)	(6.9)
Deferred taxes	20.4	(4.7)	5
Net increase in cash surrender value of company-owned life insurance	(9.7)	(11.1)	(6.1)
Stock compensation expense	4.7	9.6	8.9
Originations of mortgage loans held for sale	(351.5)	(429.5)	(817.4)
Proceeds from sales of mortgage loans held for sale	359.5	461.6	883.9
Changes in operating assets and liabilities:
(Increase) decrease in interest receivable	(10.8)	(37.8)	3.7
Decrease (increase) in other assets	80.5	(12.9)	(16.4)
Increase (decrease) in accrued interest payable	37.7	8.4	(2)
(Decrease) increase in accounts payable and accrued expenses	(71.1)	183.1	(1.7)
Net cash provided by operating activities	428	534.4	282.3
Purchases of investment securities:
Held-to-maturity	(0.5)	(858.5)	(1,238)
Available-for-sale	(134.2)	(3,309.4)	(2,717.8)
Proceeds from maturities, pay-downs, calls and sales of investment securities:
Held-to-maturity	227.3	370.5	257.6
Available-for-sale	1,390.7	1,926.5	1,118
Purchases of Federal Home Loan Bank and Federal Reserve Bank Stock	(290.8)	(241.4)	0
Proceeds from Federal Home Loan Bank and Federal Reserve Bank Stock	266.2	112.2	0
Proceeds from bank-owned life insurance settlements	5.2	1.3	1
Extensions of credit to clients, net of repayments	(185.8)	(951.4)	467.8
Proceeds from sales of OREO	3.5	3.4	1.7
Proceeds from the sale of Health Savings Accounts	0	1.4	0
Acquisition of bank and bank holding company, net of cash and cash equivalents received	0	2,006.9	0
Capital expenditures, net of sales	(28.2)	(10.5)	(10.3)
Net cash provided by (used in) investing activities	1,253.4	(949)	(2,120)
Cash flows from financing activities:
Net (decrease) increase in deposits	(1,750.5)	(2,884)	2,052.6
Net (decrease) increase in securities sold under repurchase agreements	(270.2)	28.9	(40.3)
Proceeds from (Repayments of) Other Debt	276	2,327	0
Repayments of Other Long-term Debt	0.1	164.1	0
Advances on long-term debt	0	14.3	0
Payments of Stock Issuance Costs	0	(0.8)	0
Proceeds from issuance of common stock	0	0.1	0.4
Purchase and retirement of common stock	(34)	(199)	(5.4)
Dividends paid to common stockholders	(195.1)	(182.1)	(101.6)
Net cash used in financing activities	(1,973.9)	(1,059.7)	1,905.7
Net (decrease) increase in cash and cash equivalents	(292.5)	(1,474.3)	68
Cash and cash equivalents at beginning of period	870.5	2,344.8	2,276.8
Cash and cash equivalents at end of period	578	870.5	2,344.8
Supplemental disclosures of cash flow information:
Cash paid during the period for income taxes	(51.2)	(57.8)	(56.8)
Cash paid during the period for interest expense	363.6	32	19.3
Supplemental disclosures of noncash investing and financing activities:
Transfer of held-to-maturity to available-for-sale securities	23	10.9	0
Non-cash transfer of securities from available-for-sale to held-to-maturity	0	463.6	672.2
Transfer of Loans Held-for-sale to Portfolio Loans	29.6	19.8	0
Amortization of unrealized gains and losses on transfers of securities	30.4	12.4	0
Right-of-use assets obtained in exchange for operating lease liabilities	6.4	22.9	5.9
Transfer of loans to other real estate owned	8.3	0.4	0.9
Asset Acquisition, Consideration Transferred, Equity Interest Issued and Issuable	0	1,723.3	0
Capitalization of internally originated mortgage servicing rights	1.1	2.5	3.7
Supplemental schedule of noncash investing activities from acquisitions:
Investment securities	0	2,699	0
Loans held for sale	0	217	0
Loans held for investment, net	0	7,645.5	0
Premises and equipment	0	144.7	0
Goodwill	0	479.3	0
Other intangibles	0	72.9	0
Mortgage servicing rights	0	1.3	0
Company-owned life insurance	0	186.6	0
Deferred tax assets	0	60.2	0
Other real estate owned	0	15.8	0
Other assets	0	200.8	0
Total noncash assets acquired	0	11,824.2	0
Deposits	0	11,688	0
Securities sold under repurchase agreements	0	74	0
Accounts payable and accrued expenses	0	110.4	0
Long-term debt	0	159.3	0
Subordinated debentures held by subsidiary trusts	0	76.1	0
Total liabilities assumed	0	(12,107.8)	0
Securities Purchased under Agreements to Resell, Increase	$ 0	101.1	0
Finite-Lived Intangible Assets, Gross		$ 177.5	$ 106

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business . First Interstate BancSystem, Inc. (the “Parent Company” and collectively with its subsidiaries, the “Company”) is a financial and bank holding company that, through the branch offices of its bank subsidiary, provides a comprehensive range of banking products and services to individuals, businesses, municipalities, and other entities throughout Arizona, Colorado, Idaho, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, North Dakota, Oregon, South Dakota, Washington, and Wyoming. In addition to its primary emphasis on commercial and consumer banking services, the Company also offers trust, employee benefit, investment, and insurance services through its bank subsidiary. The Company is subject to competition from other financial institutions and nonbank financial companies, and is also subject to the regulations of various government agencies and undergoes periodic examinations by those regulatory authorities. Basis of Presentation . The Company’s consolidated financial statements include the accounts of the Parent Company and its operating subsidiaries. As of December 31, 2023, the Company had one significant subsidiary, First Interstate Bank (“FIB”). All significant intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications, none of which were material, have been made in the consolidated financial statements for 2022 and 2021 to conform to the 2023 presentation. These reclassifications did not change previously reported net income or stockholders’ equity. Business Combinations. The Company accounts for all business combinations using the acquisition method of accounting. Under this method of accounting, acquired assets and assumed liabilities are included with the acquirer's accounts as of the date of acquisition, with any excess of purchase price over the fair value of the net assets acquired recognized as either finite lived intangibles or capitalized as goodwill. In addition, acquisition related costs and restructuring costs are recognized as period expenses as incurred. Fair values are subject to refinement over the measurement period, not to exceed one year after the closing date. Equity Method Investments. The Company has investments in real estate joint ventures that are not consolidated because the Company does not own a majority voting interest, control the operations, or receive a majority of the losses or earnings of the joint venture. These joint ventures are accounted for using the equity method of accounting whereby the Company initially records its investment at cost (or fair value at the date of acquisition) and then subsequently adjusts the carrying value for the Company’s proportionate share of distributions and earnings or losses of the joint ventures. Variable Interest Entities. The Company’s wholly owned business trusts, FI Statutory Trust I (“Trust I”), FI Capital Trust II (“Trust II”), FI Statutory Trust III (“Trust III”), FI Capital Trust IV (“Trust IV”), FI Statutory Trust V (“Trust V”), FI Statutory Trust VI (“Trust VI”), Northwest Bancorporation Capital Trust I (“Trust VII”), GWB Capital Trust VI (“Trust VIII”), Sunstate Bancshares Trust II (Trust IX”), Great Western Statutory Trust IV (“Trust X”), HF Financial Capital Trust III (“Trust XI”), HF Trust IV (“Trust XII”), HF Trust V (“Trust XIII”), and HF Trust VI (“Trust XIV”) are variable interest entities for which the Company is not a primary beneficiary. Accordingly, the accounts of Trust I through Trust XIV are not included in the accompanying consolidated financial statements, and are instead accounted for using the equity method of accounting. The Company has equity investments in variable interest Certified Development Entities (“CDEs”) which have received allocations under the New Markets Tax Credits Program. The underlying activities of the CDEs are community development projects designed primarily to promote community welfare, such as economic rehabilitation and development of low-income areas by providing housing, services, or jobs for residents. The maximum exposure to loss in the CDEs is the amount of equity invested and credit extended by the Company. The Company has credit protection in the form of indemnification agreements, guarantees, and collateral arrangements. Assets Held in Fiduciary or Agency Capacity. The Company holds certain trust assets in a fiduciary or agency capacity. The Company also purchases and sells federal funds as an agent. These and other assets held in an agency or fiduciary capacity are not assets of the Company and, accordingly, are not included in the accompanying consolidated financial statements. Use of Estimates. The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and income and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to change relate to the determination of the allowance for credit losses, the valuation of goodwill and intangible assets, and fair values of investment securities and other financial instruments. Cash and Cash Equivalents . For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, federal funds sold for less than three-month periods, and interest-bearing deposits in banks with original maturities of less than three months. As of December 31, 2023 and 2022, the Company had cash of $199.0 million and $518.9 million, respectively, on deposit with the Federal Reserve Bank (FRB). On March 15, 2020, the Federal Reserve reduced reserve requirement ratios to zero percent effective March 26, 2020. This action eliminated reserve requirements for all depository institutions. Debt Security Investments. Investments in debt securities that the Company has the positive intent and ability to hold to maturity are classified as held-to-maturity and carried at amortized cost. Investments in debt securities that may be sold in response to or in anticipation of changes in interest rates and resulting prepayment risk, or other factors, are classified as available-for-sale and carried at fair value. The unrealized gains and losses on these securities are reported, net of applicable income taxes, as a separate component of stockholders’ equity and comprehensive income. Management determines the appropriate classification of securities at the time of purchase and at each reporting date management reassesses the appropriateness of the classification. The amortized cost of debt securities classified as held-to-maturity or available-for-sale is adjusted for accretion of discounts to maturity and amortization of premiums over the estimated average life of the security, without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated, or in the case of callable securities, through the first call date, using the effective yield method. Such amortization and accretion is included in interest income. Realized gains and losses on sales are recorded on the trade date in investment securities gains and losses and determined using the specific identification method. Accrued interest receivable on investment securities totaled $38.5 million and $38.9 million at December 31, 2023 and 2022, respectively, and was reported in the accrued interest receivable line item on the consolidated balance sheets. Allowance for Credit Losses - Held-to-Maturity Securities: Management measures expected credit losses on held-to-maturity debt securities on a collective basis by major security type. Accrued interest receivable on held-to-maturity debt securities is excluded from the estimate of credit losses. The estimate of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Management classifies the held-to-maturity portfolio into the following major security types: U.S. Treasury notes. U.S. Treasury notes issued by the U.S. Department of the Treasury are guaranteed by the U.S. government with very little risk to default. State, county, and municipal securities. Municipal bonds issued by municipal governments within the U.S. These types of securities are primarily composed of general obligation bonds, or municipal bonds backed by the credit and taxing power of the issuing jurisdiction and revenue obligation bonds, or municipal bonds that are financed by income-producing projects and are secured by a specified source of revenue. Municipal issues shall have at least a “BBB” rating by Moody's and/or Standard and Poor’s, or equivalent creditworthiness must be established prior to purchase. All non-rated or private placement securities must be analyzed and approved by the Company’s Credit Department and documented prior to purchase. Obligations of U.S. government agencies and entities. Securities held by the Company are primarily issued by The Federal Home Loan Mortgage Corporation, known as Freddie Mac, and The Federal National Mortgage Association, known as Fannie Mae, which are implicitly guaranteed by the U.S. government and are consistently highly rated by major rating agencies with very little risk to default. U.S. agency commercial mortgage-backed securities. Commercial mortgage-backed securities held by the Company are primarily issued by U.S. government agencies and entities. These securities are either explicitly or implicitly guaranteed by the U.S. government, are consistently highly rated by major rating agencies with very little risk to default. U.S. agency residential mortgage-backed securities. Residential mortgage-backed securities held by the Company are primarily issued by U.S. government agencies and entities. These securities are either explicitly or implicitly guaranteed by the U.S. government, are consistently highly rated by major rating agencies with very little risk to default. Collateralized mortgage obligations. Collateralized mortgage obligations include agency and non-agency residential securities which carry ratings no lower than investment grade “BBB” and pass the federal financial institutions examinations test (Collateral Mortgage Obligation volatility test) at the time of purchase. Corporate securities. Securities held by the Company are primarily comprised of corporate bonds (both senior and subordinated-debt) issued by a firm or public entity which carry ratings no lower than investment grade “BBB” or better by Moody’, Standard and Poor’s, or Kroll rating agencies. All corporate subordinated-debt securities are analyzed and approved by the Company prior to purchase. Allowance for Credit Losses - Available-For-Sale Securities: For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security's amortized cost basis is written down to fair value through income. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company performs a qualitative assessment as to whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the allowance when management believes the uncollectibility of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. Accrued interest receivable on available-for-sale debt securities is excluded from the estimate of credit losses. Loans Held for Sale. The Company originates certain loans intended for sale in the secondary market. Conforming agency mortgage production is sold on a servicing retained basis. Certain loans, such as government guaranteed mortgage loans, are sold on a servicing released basis. Residential loans the Company originated with the intent to sell are classified as loans held for sale and recorded at fair value, determined individually, as of the balance sheet date. The loan’s fair value includes the servicing value of the loans as well as any accrued interest. The fair value of loans held for sale are primarily determined based on quoted prices for similar loans in active markets or outstanding commitments from third-party investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to non-interest income in the consolidated statements of operations. Net gains and losses on loan sales are recorded as a component of non-interest income. Performing residential real estate loans that are held for sale are generally sold with servicing rights retained. Upon the sale of an originated loan, the mortgage servicing right is recorded at its estimated fair value. Loans that are originated and classified as held for investment are periodically sold in order to manage liquidity, asset credit quality, interest rate risk, or concentration risk. Loans that are reclassified into loans held for sale from loans held for investment, due to a change in intent, are recorded at the lower of cost or fair value less cost to sell, except for certain loans which are recorded at fair value, determined individually, as of the balance sheet date. Any changes in fair value attributable to credit deterioration at the time of transfer are charged against the allowance for credit losses. Loans Held for Investment. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost or principal balance outstanding. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts and deferred loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized in interest income using the level-yield method without anticipating prepayments. Accrued interest receivable on loans held for investment totaled $86.1 million and $76.5 million at December 31, 2023 and 2022, respectively, and was reported in the accrued interest receivable line item on the consolidated balance sheets. Interest income is accrued on the unpaid principal balance of underlying loans. Interest income on mortgage and commercial loans is discontinued and placed on nonaccrual status at the time the loan is 90 days delinquent unless the loan is well secured and in process of collection. Mortgage loans that are 180 days past due and commercial loans are charged off to the extent principal or interest is deemed uncollectible. Consumer and credit card loans continue to accrue interest until they are charged off no later than 120 days past due unless the loan is in the process of collection. Past-due status is based on the contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful. All interest accrued but not received for loans placed on nonaccrual is reversed against interest income. Interest received on such loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. Under the cost-recovery method, interest income is not recognized until the loan balance is reduced to zero. Under the cash-basis method, interest income is recorded when the payment is received in cash. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and when, in the opinion of management, the loans are estimated to be fully collectible as to both principal and interest. Purchased Credit Deteriorated (“PCD”) Loans The Company has loans acquired through acquisitions, some of which have experienced more than insignificant credit deterioration since origination. Loans that meet at least one of the following criteria are considered to have experienced more-than-insignificant credit deterioration since origination at the date of acquisition: 1) have experienced more than one delinquency of more than 60 days or 60+ days as of the acquisition date; 2) have been placed on nonaccrual status at any point since origination; 3) are special mention, substandard, doubtful as of the acquisition date; 4) have experienced a modification to a borrower experiencing financial difficulty as of the acquisition date; or 5) are in high-risk industries based on macroeconomic conditions and local market conditions of the acquired entity on the acquisition date. PCD loans are recorded at the amount paid for the loan. An allowance for credit losses is determined using the same methodology as other loans held for investment. The initial allowance for credit losses determined on a collective basis is allocated to individual loans. The sum of the loan’s purchase price and allowance for credit losses becomes its initial amortized cost basis. The difference between the initial amortized cost basis and the par value of the loan is a noncredit discount or premium, which is amortized into interest income over the life of the loan. Subsequent changes to the allowance for credit losses are recorded through provision expense. Allowance for Credit Losses - Loans held for investment During the second quarter of 2023, the Company transitioned its Current Expected Credit Loss accounting standard (“CECL”), or ASC 326, model. The new model utilizes fewer portfolio loss segments than the old model due to limited observations of data within certain portfolio loss segments under the old model. The new model calculates historical loss rates by averaging quarterly net charge-offs for each loss segment. The loss rates are macroeconomic-conditioned and applied to loan-level expected cash flows based on contractual repayment terms. The loss rates also consider prepayment, utilization, interest rate, and probability of default assumptions. This change did not result in a material impact to the Company’s financial statements. The allowance for credit losses is a valuation account that is deducted from the loans’ amortized cost basis to present the net amount expected to be collected over the life of the loans. Loans are charged off against the allowance when management determines that a loan balance cannot be collected. The Company applies recoveries when received and has elected not to forecast recoveries for purposes of calculating the allowance for credit losses. Management estimates the allowance balance using relevant available information, from internal and external sources, relating to past events, current conditions, and reasonable and supportable forecasts. Historical credit loss experience provides the basis for the estimation of expected credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics such as differences in underwriting standards, portfolio mix and trends, asset quality, or term. Other loan-specific risk characteristics may include changes in environmental and economic conditions, such as changes in unemployment rates, property values, or other relevant factors. The allowance for credit losses is measured on a collective basis when similar risk characteristics exist. Annualized loss rates are recalculated quarterly, with subsequent recoveries captured in the quarter a loan was charged off and are averaged across a look back period from 2009 to the current period. Expected future principal and interest cash flows are calculated using contractual repayment terms while considering prepayment, utilization, interest rate, and probability of default assumptions. Macroeconomic models calculate segment-specific multipliers using third party forecast data. The multipliers adjust the annual loss rates to the level expected under the economic conditions over the 2-year forecast period, followed by a 1-year straight-line reversion to the unadjusted historical average loss rates. The unadjusted loss rates then apply for the remaining life of the loan. Estimated losses are totaled and aggregated to the portfolio segment level. The Company segments the loan portfolio into pools based on the following risk characteristics: financial asset type, collateral type, loan structure, credit characteristics, outstanding loan balances, contractual terms and prepayment assumptions, utilization assumptions, industry of borrower and concentrations, and historical or expected credit loss. The Company has identified the following portfolio segments: Real Estate loans. Include commercial real estate loans which are non-farm, non-residential real estate loans generally secured by first liens on income-producing real estate and generally mature in less than 10 years; construction development loans which are primarily to commercial builders for residential lot development and the construction of single-family residences and commercial real estate properties, commercial construction loans which are primarily made to commercial builders for the development of commercial real estate properties; and construction and development loans which are generally underwritten pursuant to credit worthiness or pre-qualification for permanent financing. During the construction phase for any of the above loans, the borrower pays interest only. In most cases, construction and development loans generally transition to a permanent real estate loans or otherwise mature in three years or less. Real estate loans also include agricultural real estate loans that generally mature in ten years or less, secured by farmland or ranchland. These loans fund the construction of short, intermediate, and long-term structures and are made to experienced agriculturalists who have demonstrated management capabilities, established production and historical financial performance. Real estate loans also include consumer home equity and home equity lines of credit (“HELOC”) that are secured by residential property and generally mature in 25 years or less, and residential loans which are loans to finance the purchase or refinance of residential property which are typically secured by first liens or are construction loans to commercial builders or owner occupants for the construction of single-family residences. Residential 1-4 family loans generally mature within 15 years, and in some instances, could mature up to 30 years. Construction loans are generally underwritten pursuant to credit worthiness or pre-qualification for permanent financing. During the construction phase the borrower pays interest only. Residential construction loans generally transition to a permanent residential loan or otherwise mature in two years or less. Consumer loans. Include indirect, direct advance lines, and credit cards. Indirect are loan contracts advanced for the purchase of automobiles, boats, and other consumer goods from the consumer product dealer networks within our market areas. Indirect dealer loans are generally secured by automobiles, recreational vehicles, boats, and other types of personal property and are made on an installment basis. Consumer indirect line loans generally mature in seven years or less. Consumer direct and advance line loans are originated for a variety of purposes including the purchase of automobiles, boats and other consumer goods, home improvements, medical expenses, vehicle repairs, debt consolidation, and planned expenses in addition to the purchase of automobiles, boats, and other consumer goods. Consumer direct and advance line loans generally mature in seven years or less. Consumer credit card loans are lines of credit offered to clients in our market areas that are generally floating rate loans and include both unsecured and secured lines. Consumer credit card loans generally do not have stated maturities but are reviewed periodically and are unconditionally cancellable. Commercial loans. Include commercial and industrial loans through a mix of variable and fixed rate commercial loans, including loans to finance showroom floor inventories and other loans for commercial purposes that are secured by 1-4 family residential property. These loans are typically made to small and medium-sized manufacturing, wholesale, retail, and service businesses for working capital needs and business expansions. Floor plan loans and commercial purpose loans secured by 1-4 family residential property generally mature in seven years or less. Commercial loans also include secured and unsecured lines of credit, business credit cards, and loans with maturities of five years or less. Outstanding balances on these commercial loans tend to be cyclical in nature. These loans are generally made with business operations as the primary source of repayment, and are typically collateralized by inventory, accounts receivable, equipment, and/or personal guarantees. Agricultural loans. Agricultural loans generally consist of short and medium-term loans and lines of credit that are primarily used for crops, livestock, equipment, and general operations. Agricultural loans are ordinarily secured by assets such as livestock or equipment and are repaid from the operations of the farm or ranch. Agricultural loans generally have maturities of seven years or less, with operating lines for one production season. Contractual Term. Expected credit losses are estimated over the contractual term of the loans, adjusted for expected prepayments, defaults, interest rates, and utilization rates. The contractual term excludes expected extensions, renewals, and modifications unless either management has a reasonable expectation at the reporting date that a modification to borrowers experiencing financial difficulty will be executed or the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancellable by the Company. A loan for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, is considered to be a modification to borrowers experiencing financial difficulty. The allowance for credit loss on a modification to borrowers experiencing financial difficulty is measured using the same method as all other loans held for investment, except when the loan is individually assessed for credit loss. Allowance for Credit Losses on Off-Balance Sheet Credit Exposures. The Company estimates expected credit losses over the contractual period in which the Company is exposed to credit risk via a contractual obligation to extend credit unless that obligation is unconditionally cancellable by the Company. Management considers our unused credit card lines and federal fund lines, extended to others, to be unconditionally cancellable. The allowance for credit losses on off-balance sheet credit exposures is adjusted as a provision for credit loss expense. The estimate considers the likelihood that funding will occur and includes expected credit losses on commitments expected to be funded over the estimated life. The Company has identified commitments to extend credit and standby letters of credit determined not to be unconditionally cancellable as categories with off-balance sheet credit exposures and uses the commitment balance, expected loss rate, expected cash flows, and utilization rate as primary assumptions to develop the allowance for credit losses on those exposures. The utilization rate represents management’s best estimate of the probability that the unfunded portion of the commitment will be funded given existing economic conditions. Goodwill . The excess purchase price over the fair value of net assets from acquisitions, or goodwill, is evaluated for impairment at least annually and on an interim basis if an event or circumstance indicates that it is likely impairment has occurred. Goodwill impairment is determined by comparing the fair value of a reporting unit to its carrying amount. In any given year the Company may elect to perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is in excess of its carrying value. If it is not more likely than not that the fair value of the reporting unit is in excess of the carrying value, or if the Company elects to bypass the qualitative assessment, a quantitative impairment test is performed. In performing a quantitative test for impairment, the fair value of net assets is estimated based on analyses of the Company’s market value, discounted cash flows and peer values. The determination of goodwill impairment is sensitive to market-based economics and other key assumptions used in determining or allocating fair value. Variability in the market and changes in assumptions or subjective measurements used to allocate fair value are reasonably possible and may have a material impact on our consolidated financial statements or results of operations. Core Deposit and Other Customer Relationship Intangibles. Intangible assets consist of core deposit intangibles and other customer relationship intangibles. Core deposit intangibles represent the intangible value of depositor relationships resulting from deposit liabilities assumed, as a result of acquisitions, and are amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is generally ten years. Other customer relationship intangibles represent the value of the identifiable intangible value assigned to customer relationships arising from acquired companies and are amortized using the straight-line method over the estimated useful life, which is 12 years. Mortgage Servicing Rights . The Company recognizes the rights to service mortgage loans for others, whether acquired or internally originated. Mortgage servicing rights are initially recorded at fair value based on comparable market data and are amortized in proportion to and over the period of estimated net servicing income. Mortgage servicing rights are evaluated quarterly for impairment by discounting the expected future cash flows, taking into consideration the estimated level of prepayments based on current industry expectations and the predominant risk characteristics of the underlying loans including loan type, note rate, and loan term. Impairment adjustments, if any, are recorded through a valuation allowance. Premises and Equipment . Buildings, furniture, and equipment are stated at cost less accumulated depreciation. Depreciation expense is computed using straight-line methods over estimated useful lives of 5 to 45 years for buildings and improvements and 3 to 15 years for furniture and equipment. Leasehold improvements and assets acquired under a financing lease are amortized over the shorter of their estimated useful lives or the terms of the related leases. Land is recorded at cost. Costs incurred for maintenance and repairs are expensed as incurred. We have leased branches and office space and have entered into various other agreements in conducting our business. Operating lease right-of-use assets are included within the Premises and Equipment line item and our operating lease liability is included within the Other Liabilities line item. Operating lease expense is recognized on a straight-line basis over the lease term, subject to any changes in the lease or expectations regarding the terms. Variable lease costs such as

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Acquisitions	ACQUISITION Great Western Bank. On September 15, 2021, the Company entered into a definitive agreement (“Agreement”) to acquire 100% of the outstanding stock of Great Western Bancorp, Inc. (“Great Western”), the parent company of Great Western Bank (“GWB”), a Sioux Falls, South Dakota based community bank with 174 banking offices across Arizona, Colorado, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota (“GWB acquisition”). The GWB acquisition expanded the Company’s geographical footprint with an enhanced platform for future growth. Consideration for the acquisition was $1,723.3 million, consisting of the issuance of 46.9 million shares of the Company’s Class A common stock valued at $36.76 per share, which was the opening price of the Company’s Class A common stock as quoted on the NASDAQ stock market on the acquisition date. The acquisition was completed on February 1, 2022. The Company accounted for the transaction under the acquisition method of accounting in accordance with ASC 805, Business Combinations , which requires purchased assets and liabilities assumed and consideration exchanged to be recorded at their respective estimated fair values at the date of acquisition. The determination of estimated fair values required management to make certain estimates about discount rates, future expected cash flows, and market conditions at the time of the acquisition, as well as other future events that are highly subjective in nature. The following table provides the purchase price allocation as of the acquisition date and the Great Western assets acquired and liabilities assumed at their estimated fair value as of the acquisition date. We recorded the estimate of fair value based on valuations at the acquisition date. The excess value of the consideration paid over the fair value of assets acquired and liabilities assumed was recorded as goodwill. The purchase price allocation resulted in goodwill of $479.3 million, of which $31.7 million is deductible for income tax purposes. Goodwill resulting from the acquisition was allocated to the Company’s one operating segment, community banking, and consists largely of the synergies and economies of scale expected from combining the operations of Great Western and the Company. All amounts reported were finalized during the fourth quarter of 2022. As of February 1, 2022 Assets acquired: Cash and cash equivalents $ 2,006.9 Investment securities 2,699.0 Securities purchased under agreement to resell 101.1 Loans held for sale 217.0 Loans held for investment 7,705.0 Allowance for credit losses (59.5) Premises and equipment, including right of use lease assets 144.7 Other real estate owned 15.8 Company owned life insurance 186.6 Core deposit intangibles 50.1 Customer relationship intangible 22.8 Mortgage servicing rights 1.3 Deferred tax assets, net 60.2 Other assets 200.8 Total assets acquired 13,351.8 Liabilities assumed: Deposits 11,688.0 Securities sold under repurchase agreements 74.0 Accrued expenses and other liabilities 110.4 FHLB advances 122.9 Subordinated debt 36.4 Subordinated debentures held by subsidiary trusts 76.1 Total liabilities assumed 12,107.8 Net assets acquired $ 1,244.0 Consideration paid: Class A common stock 1,723.3 Total consideration paid (1) $ 1,723.3 Goodwill $ 479.3 (1) Includes $13 thousand of cash paid in lieu of fractional shares. The Company determined the fair value of loans, core deposit and customer relationship intangible assets, investment securities, premises and equipment, leases, mortgage servicing rights, deposits, FHLB advances, subordinated debt, and subordinated debentures held by subsidiary trusts with the assistance of third-party valuation specialists. The following is a description of the methods used to determine the fair values of significant assets and liabilities presented above. Cash and cash equivalents The carrying amount of these assets is a reasonable estimate of fair value based on the short-term nature of these assets. Investment Securities Fair values for securities are based on quoted market prices, where available. If quoted market prices are not available, fair value estimates are based on observable inputs including quoted market prices for similar instruments, quoted market prices that are not in an active market or other inputs that are observable in the market. In the absence of observable inputs, fair value is estimated based on pricing models and/or discounted cash flow methodologies. Loans held for sale The loans held for sale portfolio was recorded at fair value based on discounted payoffs and quotes or bids from third party investors, or based on the terms of the loans, such as interest rate, maturity date, reset term, as well as sales, quotes, or bids of similar assets. Loans held for investment A valuation of the loans held for investment portfolio was performed by a third party as of the acquisition date in accordance with ASC 820 to assess the fair value of the loan portfolio, considering adjustments for interest rate risk, required equity return, servicing, credit, and liquidity risk. The loans held for investment portfolio was segmented into two groups including purchase credit deteriorated (PCD) loans and non-PCD loans. The non-PCD loans were pooled based on similar characteristics, such as loan type, fixed or adjustable interest rates, payment type, index rate and caps/floors, and non-accrual status. The PCD loans were valued at the loan level with similar characteristics noted above. The fair value was calculated using a discounted cash flow analysis to estimate the fair value of the loans using assumptions for the coupon rates, remaining maturities, prepayment speeds, projected default probabilities, loss given defaults, and estimates of prevailing discount rates. The discount rate utilized to analyze fair value considered the cost of funds rate, capital charge, servicing costs, liquidity premium, and risk premium, mostly based on industry standards. The discounted cash flow approach models the credit losses directly in the projected cash flows. The Company estimated the credit risks and principal losses of the loans using the Company’s assumptions of probability of default, loss given default, and foreclosures. The Company is required to record PCD assets, defined as a more-than-insignificant deterioration in credit quality since origination or issuance, at the purchase price plus the allowance for credit losses expected at the time of acquisition. Under this method, there is no credit loss expense affecting net income on acquisition of PCD assets. Changes in estimates of expected credit losses after acquisition are recognized in subsequent periods as credit loss expense (or reversal of credit loss expense) arise. Any non-credit discount or premium resulting from acquiring a pool of purchased financial assets with credit deterioration is allocated to each individual asset. At the acquisition date, the initial allowance for credit losses determined on a collective basis is allocated to individual assets to appropriately allocate any non-credit discount or premium. The non-credit discount or premium, after the adjustment for the allowance for credit losses, is accreted to interest income using the interest method based on the effective interest rate determined after the adjustment for credit losses at the adoption date. Information regarding loans acquired at the acquisition date as amended for measurement period adjustments as of December 31, 2022 were as follows: (In millions) PCD loans: Unpaid principal balance $ 979.2 Principal amounts previously written off by GWB (238.7) Interest applied to principal by GWB (18.1) Adjusted unpaid principal balance 722.4 Credit discount (69.2) Discount attributable to other factors (29.9) Fair value 623.3 Allowance for credit losses 59.5 Amortized cost basis 682.8 Non-PCD loans: Unpaid principal balance 7,107.9 Credit discount (1) (76.5) Non-credit discount (9.2) Fair value 7,022.2 Amortized cost basis $ 7,705.0 (1) Represents the best estimate of the contractual cash flows not expected to be collected as of the acquisition date. Core deposit intangible Core deposit intangible assets of $50.1 million on non-maturing deposits were determined by evaluating the underlying characteristics of the deposit relationships, including customer attrition, deposit interest rates and maintenance costs, and costs of alternative funding using the discounted cash flow approach. The core deposit intangibles represent the costs saved by the Company between maintaining the existing deposits and obtaining alternative funds over the life of the deposit base. These costs are amortized using an accelerated method over the estimated useful life of 10 years for the related deposits. Customer relationship intangible Customer relationship intangible assets of $22.8 million were determined using an excess earnings model associated with the expected fee income related to the underlying client relationships and is being amortized using the straight-line method over the estimated useful life of 12 years. Premises and equipment The fair values of premises are based on a market approach, using third-party appraisals and other analysis of value for land and premises. Deposits The fair values used for the demand and savings deposits equal the amounts payable on demand at the acquisition date. In determining the fair value of certificates of deposit, the cash flows of the contractual interest payments during the specific period of the certificates of deposit and scheduled principal payout were discounted to present value at market-based interest rates. FHLB advances The fair value of fixed rate FHLB advances was determined using a discounted cash flow approach. The cash flows of the advances were projected based on scheduled payments of the fixed rate advances, which factored in prepayment fees. The cash flows were then discounted to present value using the FHLB rates as of February 1, 2022. Subordinated debt and subordinated debentures held by subsidiary trusts The fair value of subordinated debt and subordinated debentures held by subsidiary trusts was determined by using a discounted cash flow method using a market participant discount rate for similar instruments over the remaining terms. Acquisition related expenses related to the GWB acquisition of $118.9 million and $11.6 million for the years ended December 31, 2022 and 2021, respectively, were included as a component of non-interest expense in the consolidated statements of income, of which approximately $26.8 million and $9.0 million were acquisition related costs as defined by ASC 805 for the years ended December 31, 2022 and 2021, respectively. During the year ended December 31, 2022, the Company contributed $21.5 million to the First Interstate Foundation and reimbursed an aggregate of $8.2 million of the Scott family control group’s acquisition expenses pursuant to the Agreement. The accompanying consolidated statements of income for the year ended December 31, 2022, include the results of operations of the acquired entity from the February 1, 2022 acquisition date. The disclosure of GWB post-acquisition revenue and net income is not practical due to the combining of certain GWB operations with and into FIB as of the acquisition date. GWB was merged with our existing bank subsidiary, First Interstate Bank, contemporaneously with the closing of the parent company merger. The core system conversion was completed on May 23, 2022. The following table presents certain pro forma financial information for the years ended December 31, 2022 and 2021 as if GWB had been acquired on January 1, 2021. This pro forma information combines the historical results of GWB with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition occurred at the beginning of the year prior to the acquisition. The pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value, cost savings, or business synergies. As a result, actual amounts would have differed from the pro forma information presented, and the differences could be significant. December 31, 2022 2021 Total revenues $ 1,223.3 $ 1,200.9 Net income $ 351.6 $ 243.3 Earnings per common share (Basic) $ 3.28 $ 2.24 Earnings per common share (Diluted) $ 3.28 $ 2.24

Goodwill and Core Deposit Intan

Goodwill and Core Deposit Intangibles	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Core Deposit Intangibles	GOODWILL AND OTHER INTANGIBLES Goodwill The following table details changes in the recorded amount of goodwill as of the dates indicated: Year Ended December 31, 2023 2022 Net carrying value at beginning of period $ 1,100.9 $ 621.6 Additions to goodwill from acquisition — 479.3 Net carrying value at end of period $ 1,100.9 $ 1,100.9 The Company performed its annual impairment assessment as of July 1, 2023 and 2022 concluding there was no impairment to goodwill. As a result of the ongoing financial services economic conditions, including changes to the interest rate environment, continued volatility in the Company’s common share price, and volatility in the Company’s overall market capitalization during the third and beginning of the fourth quarter of 2023, we performed a quantitative impairment assessment as of October 31, 2023 and concluded the fair value of our single reporting unit exceeded its respective carrying value and did not result in impairment for the reporting unit. The quantitative assessment of goodwill for the reporting unit was performed utilizing a discounted cash flow analysis (“income approach”) and estimates of selected market information (“market approaches”). The income approach measures the fair value of an interest in a business by discounting expected future cash flows to present value. The market approaches take into consideration fair values of comparable companies operating in similar lines of business that are potentially subject to similar economic and environmental factors and could be considered reasonable investment alternatives. The result of the income and market approaches were weighted in determining the fair value of the reporting unit. There were no events or circumstances that occurred subsequent to October 31, 2023 through the reporting date that would more-likely-than-not reduce the fair value of the Company’s reporting unit below its carrying value. Other Intangible Assets Other intangible assets are comprised of core deposit intangibles (“CDI”) and other customer relationship intangibles (“OCRI”) and amounted to the following at December 31, 2023 and 2022: December 31, 2023 CDI OCRI Total Gross other intangible assets, at January 1, 2023 $ 154.7 $ 22.8 $ 177.5 Accumulated amortization (92.5) (3.6) (96.1) Net other intangible assets, end of period $ 62.2 $ 19.2 $ 81.4 December 31, 2022 Gross other intangible assets, at January 1, 2022 $ 106.0 $ — $ 106.0 Amounts established through acquisition 50.1 22.8 72.9 Reductions due to sale of health savings accounts (1.4) — (1.4) Accumulated amortization (78.8) (1.7) (80.5) Net other intangible assets, end of period $ 75.9 $ 21.1 $ 97.0 The Company recorded $15.7 million, $15.9 million and $9.9 million of other intangible asset amortization expense for the years ended December 31, 2023, 2022, and 2021 respectively. CDI and OCRI are evaluated for impairment if events and circumstances indicate a possible impairment. CDI is amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is generally 10 years. OCRI is amortized using a straight-line method over its estimated useful life of 12 years based on customer revenue attrition on an annualized basis. The following table provides the estimated aggregate future amortization expense of other intangible assets: Years ending December 31, CDI OCRI Total 2024 $ 12.7 $ 1.9 $ 14.6 2025 11.8 1.9 13.7 2026 10.9 1.9 12.8 2027 8.2 1.9 10.1 2028 5.7 1.9 7.6 Thereafter 12.9 9.7 22.6 Total $ 62.2 $ 19.2 $ 81.4

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Investment Securities	INVESTMENT SECURITIES The amortized cost and the approximate fair values of investment securities are summarized as follows: December 31, 2023 Amortized Allowance for Credit Losses Net Amortized Cost Gross Gross Estimated Available-for-Sale: U.S. Treasury notes $ 250.2 $ — $ 250.2 $ — $ (25.5) $ 224.7 State, county, and municipal securities 256.7 — 256.7 — (36.9) 219.8 Obligations of U.S. government agencies 179.4 — 179.4 — (10.9) 168.5 U.S. agency commercial mortgage-backed securities 1,192.7 — 1,192.7 0.6 (87.7) 1,105.6 U.S. agency residential mortgage-backed securities 1,496.3 — 1,496.3 1.2 (130.6) 1,366.9 Collateralized mortgage obligations 1,308.5 — 1,308.5 1.3 (120.3) 1,189.5 Private mortgage-backed securities 241.3 — 241.3 — (30.9) 210.4 Collateralized loan obligations 1,121.9 — 1,121.9 0.1 (2.3) 1,119.7 Corporate securities 260.8 — 260.8 — (24.4) 236.4 Total $ 6,307.8 $ — $ 6,307.8 $ 3.2 $ (469.5) $ 5,841.5 December 31, 2023 Amortized Cost 1 Allowance for Credit Losses Net Amortized Cost Gross Unrealized Gains Gross Estimated Held-to Maturity: U.S. Treasury notes $ 399.0 $ — $ 399.0 $ — $ (2.8) $ 396.2 State, county, and municipal securities 179.2 — 179.2 0.2 (24.2) 155.2 Obligations of U.S. government agencies 354.5 — 354.5 — (42.4) 312.1 U.S. agency commercial mortgage-backed securities 510.5 — 510.5 — (52.9) 457.6 U.S. agency residential mortgage-backed securities 1,232.6 — 1,232.6 — (137.0) 1,095.6 Collateralized mortgage obligations 475.9 — 475.9 0.2 (69.0) 407.1 Corporate securities 57.0 (0.8) 56.2 — (6.0) 50.2 Total $ 3,208.7 $ (0.8) $ 3,207.9 $ 0.4 $ (334.3) $ 2,874.0 (1) Amortized cost presented above includes $10.7 million of unamortized gains in U.S. agency residential and commercial mortgage-backed securities and collateralized mortgage obligations related to the 2021 transfer of securities from available-for-sale to held-to-maturity, and $18.1 million of unamortized losses in state, county, and municipal, obligations of U.S. government agencies and corporate securities related to the 2022 transfer of securities from available-for-sale to held-to-maturity. December 31, 2022 Amortized Allowance for Credit Losses Net Amortized Cost Gross Gross Estimated Available-for-Sale U.S. Treasury notes $ 675.1 $ — $ 675.1 $ 2.1 $ (34.5) $ 642.7 State, county, and municipal securities 314.3 — 314.3 — (50.6) 263.7 Obligations of U.S. government agencies 216.2 — 216.2 — (17.3) 198.9 U.S. agency commercial mortgage-backed securities 1,468.0 — 1,468.0 0.2 (117.0) 1,351.2 U.S. agency residential mortgage-backed securities 1,726.0 — 1,726.0 — (167.7) 1,558.3 Collateralized mortgage obligations 1,491.5 — 1,491.5 — (141.3) 1,350.2 Private mortgage-backed securities 264.9 — 264.9 — (36.9) 228.0 Collateralized loan obligations 1,145.2 — 1,145.2 — (33.6) 1,111.6 Corporate securities 272.3 — 272.3 — (30.8) 241.5 Total $ 7,573.5 $ — $ 7,573.5 $ 2.3 $ (629.7) $ 6,946.1 December 31, 2022 Amortized Cost 1 Allowance for Credit Losses Net Amortized Cost Gross Gross Estimated Held-to Maturity U.S. Treasury notes $ 396.6 $ — $ 396.6 $ — $ (10.2) $ 386.4 State, county, and municipal securities 181.2 (0.1) 181.1 0.2 (31.6) 149.7 Obligations of U.S. government agencies 351.7 — 351.7 — (49.6) 302.1 U.S. agency commercial mortgage-backed securities 526.8 — 526.8 — (58.3) 468.5 U.S. agency residential mortgage-backed securities 1,391.5 — 1,391.5 — (166.6) 1,224.9 Collateralized mortgage obligations 525.8 — 525.8 0.2 (76.7) 449.3 Corporate securities 80.1 (1.8) 78.3 — (7.0) 71.3 Total $ 3,453.7 $ (1.9) $ 3,451.8 $ 0.4 $ (400.0) $ 3,052.2 (1) Amortized cost presented above includes $20.2 million of unamortized losses and of $14.2 million unamortized gains related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity. The following tables show the gross unrealized losses and fair values of available-for-sale investment securities and the length of time individual investment securities have been in an unrealized loss position as of December 31, 2023 and 2022. Less than 12 Months 12 Months or More Total December 31, 2023 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ — $ — $ 224.7 $ (25.5) $ 224.7 $ (25.5) State, county, and municipal securities — — 217.1 (36.9) 217.1 (36.9) Obligations of U.S. government agencies — — 168.0 (10.9) 168.0 (10.9) U.S. agency commercial mortgage-backed securities 0.2 — 1,083.1 (87.7) 1,083.3 (87.7) U.S. agency residential mortgage-backed securities 0.7 — 1,287.5 (130.6) 1,288.2 (130.6) Collateralized mortgage obligations — — 1,142.4 (120.3) 1,142.4 (120.3) Private mortgage-backed securities — — 210.5 (30.9) 210.5 (30.9) Collateralized loan obligations — — 935.7 (2.3) 935.7 (2.3) Corporate securities — — 236.5 (24.4) 236.5 (24.4) Total $ 0.9 $ — $ 5,505.5 $ (469.5) $ 5,506.4 $ (469.5) Less than 12 Months 12 Months or More Total December 31, 2022 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ 168.8 $ (4.7) $ 170.4 $ (29.8) $ 339.2 $ (34.5) State, county, and municipal securities 104.9 (9.0) 146.1 (41.6) 251.0 (50.6) Obligations of U.S. government agencies 152.2 (10.1) 46.1 (7.2) 198.3 (17.3) U.S. agency commercial mortgage-backed securities 1,069.8 (59.9) 270.8 (57.0) 1,340.6 (116.9) U.S. agency residential mortgage-backed securities 1,213.5 (112.3) 344.6 (55.4) 1,558.1 (167.7) Collateralized mortgage obligations 1,016.4 (90.1) 333.0 (51.3) 1,349.4 (141.4) Private mortgage-backed securities 133.1 (19.1) 94.9 (17.8) 228.0 (36.9) Collateralized loan obligations 1,082.6 (33.1) 28.9 (0.5) 1,111.5 (33.6) Corporate securities 130.6 (8.3) 110.8 (22.5) 241.4 (30.8) Total $ 5,071.9 $ (346.6) $ 1,545.6 $ (283.1) $ 6,617.5 $ (629.7) As of December 31, 2023 and 2022, there were no holdings of securities of any issuer, other than the U.S. government and its agencies, in an amount greater than 10% of stockholders’ equity. The Company acquired $2,699.0 million of investment securities in connection with the acquisition of GWB. Such securities were evaluated and it was determined that there were no investment securities that met the definition of a PCD asset and none were classified as PCD upon acquisition. The Company determines credit losses on both available-for-sale and held-to-maturity investment securities by a discounted cash flow approach using the security’s effective interest rate at the time of purchase or upon acquisition. The allowance for credit losses is measured as the amount by which an investment security’s amortized cost exceeds the net present value of expected future cash flows. However, the amount of credit losses for available-for-sale investment securities is limited to the amount of a security’s unrealized loss. Credit losses on held-to-maturity investment securities are representative of current expected credit losses that management expects to be incurred over the life of the investment. The allowance for credit losses is established through a charge to provision for credit losses in current period earnings. The available-for-sale securities portfolio primarily contains securities that are guaranteed by a sovereign entity or are generally considered to have non-credit related risks, such as interest rate risk or prepayment and liquidity factors. The Company considers whether the securities are issued by the federal government or its agencies and whether downgrades by bond rating agencies have occurred. As of December 31, 2023 and 2022, the Company had 995 and 1,222 individual investment securities, respectively, that were in an unrealized loss position, which was related primarily to fluctuations in current interest rates. As of December 31, 2023, the Company had the intent and ability to hold these investment securities for a period of time sufficient to allow for an anticipated recovery. The Company does not intend to sell any of the available-for-sale securities in the above table, and the Company does not anticipate it will have to sell any securities before a recovery in cost. The following table presents the activity in the allowance for credit losses related to held-to-maturity investment securities: Year Ended December 31, 2023 2022 2021 Beginning balance $ 1.9 $ — $ — (Reduction of) provision for credit losses (1.1) 1.9 — Ending balance $ 0.8 $ 1.9 $ — The Company had no allowance for credit losses for available-for-sale corporate investment securities as of December 31, 2023 and 2022, respectively. The Company had a $0.8 million and a $1.9 million allowance for credit losses for held-to-maturity corporate and state, county, and municipal investment securities as of December 31, 2023 and 2022, respectively. On a quarterly basis, the Company refreshes the credit quality indicator of each held-to-maturity security. The following table summarizes the credit quality indicators of held-to-maturity securities at amortized cost for the periods indicated: December 31, 2023 AAA AA A BBB BB Not Rated Total U.S. Treasury notes $ 399.0 $ — $ — $ — $ — $ — $ 399.0 State, county, and municipal securities 69.0 92.3 10.6 — — 7.3 179.2 Obligations of U.S. government agencies 354.5 — — — — — 354.5 U.S. agency commercial mortgage-backed securities FNMA/FHLMC 359.7 — — — — — 359.7 GNMA 150.8 — — — — — 150.8 U.S. agency residential mortgage-backed securities FNMA/FHLMC 1,189.8 — — — — — 1,189.8 GNMA 42.8 — — — — — 42.8 Collateralized mortgage obligations FNMA/FHLMC 334.1 — — — — — 334.1 GNMA 141.8 — — — — — 141.8 Corporate securities — — — 47.0 5.0 5.0 57.0 Total $ 3,041.5 $ 92.3 $ 10.6 $ 47.0 $ 5.0 $ 12.3 $ 3,208.7 December 31, 2022 AAA AA A BBB BB Not Rated Total U.S. Treasury notes $ 396.6 $ — $ — $ — $ — $ — $ 396.6 State, county, and municipal securities 68.3 92.8 11.5 — — 8.6 181.2 Obligations of U.S. government agencies 351.7 — — — — — 351.7 U.S. agency commercial mortgage-backed securities FNMA/FHLMC 364.9 — — — — — 364.9 GNMA 161.9 — — — — — 161.9 U.S. agency residential mortgage-backed securities FNMA/FHLMC 1,342.9 — — — — — 1,342.9 GNMA 48.6 — — — — — 48.6 Collateralized mortgage obligations FNMA/FHLMC 525.8 — — — — — 525.8 Corporate securities — — — 65.1 10.0 5.0 80.1 Total $ 3,260.7 $ 92.8 $ 11.5 $ 65.1 $ 10.0 $ 13.6 $ 3,453.7 As of December 31, 2023 and 2022, the Company had $38.5 million and $38.9 million, respectively, of accrued interest receivable from investment securities on the consolidated balance sheets. Accrued interest receivable is presented as a separate line item on the consolidated balance sheets and the Company does not include accrued interest receivable in the carrying amount of financial assets held at the amortized cost basis or in the related allowance for credit losses calculation. As of December 31, 2023 and 2022, there were no available-for-sale or held-to-maturity securities on nonaccrual status. All securities in the portfolio were current with their contractual principal and interest payments. As of December 31, 2023 and 2022, there were no collateral-dependent available-for-sale or held-to-maturity securities. For the year ended December 31, 2023, there were no material gross realized gains and $23.5 million in gross realized losses on the disposition of available-for-sale investment securities, as a result of the sale of $853.0 million in carrying value of investment securities. For the year ended December 31, 2022, there were $0.3 million gross realized gains and $46.8 million gross realized losses on the disposition of available-for-sale investment securities. There were $3.2 million material gross realized gains and 2.1 million material gross realized losses on the disposition of available-for-sale investment securities for the year ended December 31, 2021. Maturities of securities do not reflect rate repricing opportunities present in adjustable-rate mortgage-backed securities. Maturities of mortgage-backed securities have been adjusted to reflect shorter maturities based upon estimated prepayments of principal. All other investment securities maturities are shown at contractual maturity dates. Available-for-Sale Held-to-Maturity December 31, 2023 Amortized Estimated Amortized Estimated Within one year $ 40.1 $ 39.4 $ 309.1 $ 307.5 After one year but within five years 1,004.4 938.7 346.6 329.4 After five years but within ten years 1,373.9 1,255.4 654.0 579.1 After ten years 3,889.4 3,608.0 1,899.0 1,658.0 Total $ 6,307.8 $ 5,841.5 $ 3,208.7 $ 2,874.0 As of December 31, 2023, the Company held investment securities callable within one year having amortized costs and estimated fair values of $1,603.3 million and $1,552.2 million, respectively. These investment securities are primarily included in the “after ten years” category in the table above. As of December 31, 2023, the Company had no callable structured notes. As of December 31, 2023 and 2022, the Company had amortized costs of $3,858.6 million and $4,998.9 million, respectively, for investment securities pledged to secure public deposits, securities sold under repurchase agreements, and as collateral for FHLB and the FRB term funding program line capacity that had estimated fair values as of December 31, 2023 and 2022 of $3,462.2 million and $4,432.0 million, respectively. All securities sold under repurchase agreements are with clients and mature on the next banking day. The Company retains possession of the underlying securities sold under repurchase agreements. As of December 31, 2023 and 2022, the Company held $223.2 million and $198.6 million, respectively, in equity securities in a combination of Federal Reserve Bank and Federal Home Loan Bank stocks, which are restricted nonmarketable securities acquired to meet regulatory requirements. These securities are carried at cost.

Loans Held for Sale

Loans Held for Sale	12 Months Ended
	Dec. 31, 2023
Loans Held for Sale [Abstract]
Loans Held for Sale	The following table presents loans held for sale by class of receivable for the dates indicated: December 31, December 31, Loans held for sale: Agricultural 1 $ 19.6 $ 62.5 Commercial real estate, at lower of cost or market 27.3 — Construction real estate, at lower of cost or market — 10.5 Residential mortgage, at fair value 0.5 6.9 Total loans held for sale $ 47.4 $ 79.9 1 As of December 31, 2023 the agricultural loans held were at lower of cost or market. At December 31, 2022, the Company held $57.0 million of agricultural loans at lower of cost or market and $5.5 million of agricultural loans on accrual status at fair value with an unpaid principal balance of $7.7 million, of which $5.6 million is 90 days or more past due. The table below presents the non-residential mortgage loans held for sale activity for the 2023 period: Agricultural Construction Real Estate Commercial Real Estate Beginning balance $ 62.5 $ 10.5 $ — Loans held for investment transferred to loans held for sale — 3.1 27.3 Loans held for sale transferred to loans held for investment (29.6) — — Loans held for sale transferred to OREO — (6.4) — Repayments and discounted pay-offs (15.5) — — Loan disposals — (3.1) — Increase (decrease) in estimated fair value of the loans 1 2.2 (4.1) — Ending balance $ 19.6 $ — $ 27.3 1 For the year ended December 31, 2023, the Company recorded a gain of $2.2 million and a loss of $4.1 million in other income within the consolidated statements of income related to fair value changes.

Loans Held for Investment

Loans Held for Investment	12 Months Ended
	Dec. 31, 2023
Receivables [Abstract]
Loans	LOANS HELD FOR INVESTMENT The following table presents loans by class of receivable and portfolio segment as of the dates indicated: 2023 2022 Real estate: Commercial $ 8,869.2 $ 8,528.6 Construction 1,826.5 1,944.4 Residential 2,244.3 2,188.3 Agricultural 716.8 794.9 Total real estate 13,656.8 13,456.2 Consumer: Indirect 740.9 829.7 Direct and advance lines 141.6 152.9 Credit card 76.5 75.9 Total consumer 959.0 1,058.5 Commercial 2,906.8 2,882.6 Agricultural 769.4 708.3 Other, including overdrafts 0.1 9.2 Loans held for investment 18,292.1 18,114.8 Deferred loan fees and costs (12.5) (15.6) Loans held for investment, net of deferred fees and costs 18,279.6 18,099.2 Allowance for credit losses (227.7) (220.1) Net loans held for investment $ 18,051.9 $ 17,879.1 Allowance for Credit Losses The following tables represent, by loan portfolio segments, the activity in the allowance for credit losses for loans held for investment: December 31, 2023 Beginning Balance Provision for (reversal of) Loans Charged-Off (2) Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate $ 138.7 $ 35.2 $ (18.5) $ 4.7 $ 160.1 Consumer 23.3 (1.0) (14.0) 4.7 13.0 Commercial 54.9 (3.9) (3.4) 2.6 50.2 Agricultural 3.2 0.8 — 0.4 4.4 Total allowance for credit losses $ 220.1 $ 31.1 $ (35.9) $ 12.4 $ 227.7 December 31, 2022 Beginning Balance ACL Recorded for PCD Loans Provision for (reversal of) Credit Loss Loans Charged-Off (2) Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 17.3 $ 17.2 $ (4.2) $ (3.5) $ 0.4 $ 27.2 Owner occupied 13.3 9.5 (2.7) (2.5) 1.9 19.5 Multi-family 13.3 10.9 8.7 (5.7) 0.7 27.9 Total commercial real estate 43.9 37.6 1.8 (11.7) 3.0 74.6 Construction: Land acquisition & development 0.5 3.4 (0.4) (2.6) 0.4 1.3 Residential construction 2.4 — 1.1 — 0.1 3.6 Commercial construction 6.0 0.2 31.6 (6.6) — 31.2 Total construction 8.9 3.6 32.3 (9.2) 0.5 36.1 Residential real estate: Residential 1-4 family 13.4 0.1 6.9 (0.2) 0.3 20.5 Home equity and HELOC 1.2 — — (0.1) 0.5 1.6 Total residential real estate 14.6 0.1 6.9 (0.3) 0.8 22.1 Agricultural real estate 1.9 2.3 1.5 (0.2) 0.4 5.9 Total real estate 69.3 43.6 42.5 (21.4) 4.7 138.7 Consumer: Indirect 14.3 — 2.7 (4.0) 2.3 15.3 Direct and advance lines 4.6 — 2.2 (3.7) 2.1 5.2 Credit card 2.2 — 2.4 (2.4) 0.6 2.8 Total consumer 21.1 — 7.3 (10.1) 5.0 23.3 Commercial: Commercial and floor plans 27.1 11.2 15.1 (6.6) 2.2 49.0 Commercial purpose secured by 1-4 family 4.4 0.2 1.2 (0.2) 0.1 5.7 Credit card 0.1 — 1.4 (1.3) — 0.2 Total commercial 31.6 11.4 17.7 (8.1) 2.3 54.9 Agricultural: Agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total allowance for credit losses $ 122.3 $ 59.5 $ 68.4 $ (45.0) $ 14.9 $ 220.1 December 31, 2021 Beginning Balance Provision for (reversal of) Credit Loss Loans Charged-Off (2) Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 25.5 $ (8.3) $ — $ 0.1 $ 17.3 Owner occupied 18.3 (2.7) (2.3) — 13.3 Multi-family 11.0 2.3 — — 13.3 Total commercial real estate 54.8 (8.7) (2.3) 0.1 43.9 Construction: Land acquisition & development 1.3 (0.1) (1.2) 0.5 0.5 Residential construction 1.6 0.9 (0.1) — 2.4 Commercial construction 7.3 (1.3) (0.1) 0.1 6.0 Total construction 10.2 (0.5) (1.4) 0.6 8.9 Residential real estate: Residential 1-4 family 11.4 2.0 — — 13.4 Home equity and HELOC 1.4 (0.4) (0.1) 0.3 1.2 Total residential real estate 12.8 1.6 (0.1) 0.3 14.6 Agricultural real estate 2.7 (0.1) (0.7) — 1.9 Total real estate 80.5 (7.7) (4.5) 1.0 69.3 Consumer: Indirect 16.7 (1.4) (3.5) 2.5 14.3 Direct and advance lines 4.6 1.7 (2.9) 1.2 4.6 Credit card 2.6 0.6 (1.8) 0.8 2.2 Total consumer 23.9 0.9 (8.2) 4.5 21.1 Commercial: Commercial and floor plans 34.2 (7.3) (3.0) 3.2 27.1 Commercial purpose secured by 1-4 family 4.7 (0.5) (0.3) 0.5 4.4 Credit card 0.3 0.1 (0.4) 0.1 0.1 Total commercial 39.2 (7.7) (3.7) 3.8 31.6 Agricultural: Agricultural 0.7 (0.2) (0.2) — 0.3 Total agricultural 0.7 (0.2) (0.2) — 0.3 Total allowance for credit losses $ 144.3 $ (14.7) $ (16.6) $ 9.3 $ 122.3 (1) Amounts presented exclude the allowance for credit losses related to unfunded commitments and investment securities. The allowance for credit losses related to unfunded commitments and investment securities are included in the “Financial Instruments with Off-Balance Sheet Risk” Note and “Investment Securities” Note, respectively. (2) Loans, or portions thereof, are charged-off against the allowance for credit losses when management believes the collectability of the principal is unlikely, or, with respect to consumer installment loans, according to an established delinquency schedule. Collateral-Dependent Loans A collateral-dependent financial loan relies substantially on the operation or sale of the collateral securing the loan for repayment. A loan may become collateral-dependent when foreclosure is probable or the borrower is experiencing financial difficulty and its sources of repayment become inadequate over time. At such time, the Company develops an expectation that repayment will be provided substantially through the operation or sale of the collateral. The following tables present the principal balance of collateral-dependent loans by class of receivable as of the dates indicated: Collateral Type As of December 31, 2023 Business Assets Real Property Other Total Real estate: Commercial $ — $ 26.6 $ — $ 26.6 Construction — 17.0 — 17.0 Residential — 0.5 — 0.5 Agricultural — 1.2 — 1.2 Total real estate — 45.3 — 45.3 Commercial 4.5 1.4 0.7 6.6 Agricultural 0.7 — — 0.7 Total collateral-dependent loans $ 5.2 $ 46.7 $ 0.7 $ 52.6 Collateral Type As of December 31, 2022 Business Assets Real Property Other Total Real estate: Commercial $ 1.7 $ 15.8 $ — $ 17.5 Construction — 3.2 — 3.2 Residential — 0.5 — 0.5 Agricultural 0.2 5.8 — 6.0 Total real estate 1.9 25.3 — 27.2 Commercial 3.1 1.5 — 4.6 Agricultural 2.1 5.2 — 7.3 Total collateral-dependent loans $ 7.1 $ 32.0 $ — $ 39.1 Aging Analysis Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans classified in the following table as 90 days or more past due continue to accrue interest. The following tables present the contractual aging of the Company’s recorded principal balance of loans by class of receivable as of the dates indicated: Total Loans 30 - 59 60 - 89 90 or more 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2023 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 12.7 $ 6.1 $ — $ 18.8 $ 8,822.2 $ 28.2 $ 8,869.2 Construction 3.1 0.4 — 3.5 1,805.8 17.2 1,826.5 Residential 11.9 3.1 0.6 15.6 2,218.0 10.7 2,244.3 Agricultural 1.8 — — 1.8 709.6 5.4 716.8 Total real estate 29.5 9.6 0.6 39.7 13,555.6 61.5 13,656.8 Consumer: Indirect 8.0 2.2 0.4 10.6 727.6 2.7 740.9 Direct 0.9 0.2 — 1.1 140.2 0.3 141.6 Credit card 0.7 0.5 0.6 1.8 74.7 — 76.5 Total consumer 9.6 2.9 1.0 13.5 942.5 3.0 959.0 Commercial 14.5 1.1 0.3 15.9 2,879.4 11.5 2,906.8 Agricultural 0.1 — 3.0 3.1 735.9 30.4 769.4 Other, including overdrafts — — — — 0.1 — 0.1 Loans held for investment $ 53.7 $ 13.6 $ 4.9 $ 72.2 $ 18,113.5 $ 106.4 $ 18,292.1 Total Loans 30 - 59 60 - 89 90 or more 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2022 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 5.6 $ 0.8 $ 1.1 $ 7.5 $ 8,501.5 $ 19.6 $ 8,528.6 Construction 10.4 0.6 0.6 11.6 1,929.1 3.7 1,944.4 Residential 9.9 2.1 1.2 13.2 2,168.7 6.4 2,188.3 Agricultural 1.1 6.1 — 7.2 780.1 7.6 794.9 Total real estate 27.0 9.6 2.9 39.5 13,379.4 37.3 13,456.2 Consumer: Indirect 9.3 2.4 0.6 12.3 814.7 2.7 829.7 Direct 0.8 0.3 0.1 1.2 151.4 0.3 152.9 Credit card 0.8 0.4 0.6 1.8 74.1 — 75.9 Total consumer 10.9 3.1 1.3 15.3 1,040.2 3.0 1,058.5 Commercial 7.1 1.7 2.1 10.9 2,861.5 10.2 2,882.6 Agricultural 0.8 2.2 0.1 3.1 696.5 8.7 708.3 Other, including overdrafts — — — — 9.2 — 9.2 Loans held for investment $ 45.8 $ 16.6 $ 6.4 $ 68.8 $ 17,986.8 $ 59.2 $ 18,114.8 (1) As of December 31, 2023 and 2022, none of our non-accrual loans were earning interest income. Additionally, no material interest income was recognized on non-accrual loans at December 31, 2023 and 2022, respectively. There were $2.7 million and $1.5 million in reversals of accrued interest at December 31, 2023 and 2022, respectively. Modifications to Borrowers Experiencing Financial Difficulty Modifications of loans are made in the ordinary course of business and are completed on a case-by-case basis through negotiation with the borrower in connection with the ongoing loan collection processes. Loan modifications are made to provide borrowers payment relief. Effective January 1, 2023, the Company adopted ASU 2022-02, which eliminated accounting guidance for troubled debt restructurings while requiring disclosures of borrowers experiencing financial difficulty for modifications related to principal reductions, interest rate reductions, term extensions, and more than insignificant payment delay. See “Note 17 – Recent Authoritative Accounting Guidance” of these Notes to Unaudited Consolidated Financial Statements” for further discussion of the amendments in this update. From time to time, we may modify certain loans to borrowers who are experiencing financial difficulty. In some cases, these modifications may result in new loans. Loan modifications to borrowers experiencing financial difficulty may be in the form of principal forgiveness, an interest rate reduction, an other-than-insignificant payment delay, or a term extension or a combination thereof, among other things. The following table presents the amortized cost basis of loans at December 31, 2023 that were both experiencing financial difficulty and modified during the year ended December 31, 2023, by class and by type of modification. The percentage of the principal balance of loans that were modified to borrowers in financial difficulty as compared to the principal balance of each class of receivable is also presented below: December 31, 2023 Principal Forgiveness Term Extension Rate Reduction Term Extension and Interest Rate Reduction Total % of Total Class of Loans Held for Investment (1) Real estate: Commercial $ 1.5 $ 28.6 $ 1.1 $ 0.6 $ 31.8 0.36 % Construction — 13.7 — — 13.7 0.75 Residential 0.1 0.6 — — 0.7 0.03 Agricultural — 6.4 — — 6.4 0.89 Total real estate 1.6 49.3 1.1 0.6 52.6 0.39 Consumer: Indirect — 0.1 — — 0.1 0.01 Direct and advance lines — 0.1 — — 0.1 0.07 Total consumer — 0.2 — — 0.2 0.02 Commercial — 7.4 — 0.2 7.6 0.26 Agricultural — 36.1 — — 36.1 4.69 Loans held for investment (2) $ 1.6 $ 93.0 $ 1.1 $ 0.8 $ 96.5 0.53 % (1) Based on the principal balance as of period end, divided by the period end principal balance of the corresponding class of receivables. (2) As of December 31, 2023, the Company excluded $1.6 million in accrued interest from the amortized cost of the identified loans. The Company monitors the performance of loan modifications to borrowers experiencing financial difficulty to understand the effectiveness of its modification efforts. Of the loans that were modified during the year ended December 31, 2023, there were $6.7 million of loans classified as past due 30 days or more, with the remaining loans performing in accordance with the modified terms and are classified as current at December 31, 2023. There were no commitments to lend additional funds to borrowers experiencing financial difficulty whose terms have been modified during the year ended December 31, 2023 through either principal forgiveness, interest rate reduction, term extension, or other than insignificant payment delay. The following table presents the financial effect of the loan modifications presented above to borrowers experiencing financial difficulty during the year ended December 31, 2023: Term Extension and Interest Rate Reduction Principal Forgiveness Weighted-Average Months of Term Extension Weighted-Average Interest Rate Reduction Weighted-Average Months of Term Extension Weighted-Average Interest Rate Reduction Real estate: Commercial $ 1.3 5.8 0.35 % 6.0 0.25 % Construction — 9.1 — 0.0 — Residential 0.3 131.6 — 0.0 — Agricultural — 4.5 — 0.0 — Total real estate 1.6 Consumer: Indirect — 8.3 — 0.0 — Direct and advance lines — 62.1 — 0.0 — Total consumer — Commercial — 12.2 — 14.6 0.51 Agricultural — 9.2 — 0.0 — Loans held for investment (1) $ 1.6 (1) Balances based on loan original contractual terms. There were no payment defaults on these loans subsequent to their modifications during the year ended December 31, 2023. The Company considers a payment default to occur when the loan is 90 days or more past due or the loan is placed on non-accrual status after the modification. The Company monitors the performance of modified loans on an ongoing basis. In the event of subsequent default, the allowance for credit losses continues to be reassessed on the basis of an individual evaluation of each loan. The modifications made during the periods presented did not significantly impact the Company’s determination of the allowance for credit losses. Purchased Credit Deteriorated Loans (“PCD”) The Company analyzes all acquired loans at the time of acquisition for more-than-insignificant deterioration in credit quality since their origination date. Such loans are classified as PCD, also referred to as PCD loans. Acquired loans classified as PCD are recorded at an initial amortized cost, which is comprised of the purchase price of the loans plus the initial allowance for credit losses for the loans, and any resulting discount or premium related to factors other than credit. The Company accounts for interest income on PCD loans using the interest method, whereby any purchase discounts or premiums are accreted or amortized into interest income as an adjustment of the loan’s yield. The following table reconciles the par value, or initial amortized cost, of PCD loans acquired in the GWB acquisition as of February 1, 2022, or the date of the acquisition with the purchase price (or initial fair value of the loans) as amended for measurement period adjustments: Purchase price (initial fair value) $ 623.3 Allowance for credit losses (1) 298.2 Discount attributable to other factors (2) 57.7 Par value (unpaid principal balance) $ 979.2 (1) For acquired PCD loans, an allowance of $298.2 million was required with a corresponding increase to the amortized cost basis as of the acquisition date. For PCD loans where all or a portion of the loan balance had been previously written-off by GWB, or would be subject to write-off under the Company’s charge-off policy, a CECL allowance of $238.7 million, included as part of the grossed-up loan balance at acquisition was immediately written-off. The net impact to the allowance for PCD assets on the acquisition date was $59.5 million. (2) Non-credit discount includes the difference between the amortized cost basis and the unpaid principal balance of $39.6 million established on PCD loans acquired from GWB and interest applied to principal of $18.1 million. Credit Quality Indicators As part of the on-going and continuous monitoring of the credit quality of the Company’s loan portfolio, management tracks internally assigned risk classifications of loans based on relevant information about the ability of borrowers to service their debt. The factors considered by the Company include, among other factors, the borrower’s current financial information, historical payment experience, credit documentation, public information, and current economic trends. The Company analyzes loans individually to classify the credit risk of the loans. This analysis generally includes loans with an outstanding balance greater than $1.0 million, which are generally considered non-homogeneous loans, such as commercial loans and commercial real estate loans. This analysis is performed no less than on an annual basis, depending upon the size of exposure and the contractual obligations governing the borrower’s financial reporting frequency. Homogeneous loans, including small business loans, are typically monitored by payment performance. The Company internally risk rates its loans in accordance with a Uniform Classification System developed jointly by the various bank regulatory agencies. The Uniform Classification System defines three broad categories of criticized assets, which the Company uses as credit quality indicators in addition to the 6 Pass ratings in its 10-point rating scale: Special Mention — includes loans that exhibit a potential weakness in financial condition, loan structure, or documentation that warrants management’s close attention. If not promptly corrected, the potential weaknesses may result in deterioration of the repayment prospects for the loan or of the institution’s credit position at some future date. Substandard — includes loans that are inadequately protected by the current net worth and paying capacity of the borrower which have well-defined weaknesses that jeopardize the liquidation of the debt. Although the primary source of repayment for a substandard loan may not currently be sufficient, collateral or other sources of repayment are sufficient to satisfy the debt. Continuance of a substandard loan is not warranted unless positive steps are taken to improve the worthiness of the credit. Doubtful — includes loans that exhibit pronounced weaknesses based on currently existing facts, conditions, and values to a point where collection or liquidation for full repayment is highly questionable and improbable. Doubtful loans are required to be placed on non-accrual status and are assigned specific loss exposure. Loans not meeting the criteria above that are analyzed individually as part of the above-described process are considered pass-rated loans. The Company evaluates the credit quality and loan performance for the allowance for credit losses of the following class of receivables based on the aforementioned risk scale as of and for the periods ended: December 31, 2023 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2023 2022 2021 2020 2019 Prior Revolving Loans Amortized Cost Basis Revolving Loans Converted To Term Total Commercial real estate: Pass $ 1,268.0 $ 2,065.0 $ 1,612.2 $ 1,200.1 $ 716.5 $ 1,660.5 $ 46.5 $ 28.1 $ 8,596.9 Special mention 4.2 9.1 42.6 12.9 27.5 17.1 0.3 — 113.7 Substandard 65.4 11.8 18.9 2.4 30.1 28.5 0.2 — 157.3 Doubtful — — 1.3 — — — — — 1.3 Total $ 1,337.6 $ 2,085.9 $ 1,675.0 $ 1,215.4 $ 774.1 $ 1,706.1 $ 47.0 $ 28.1 $ 8,869.2 Current-period gross charge-offs 1.7 0.3 1.7 2.6 — 1.3 — — 7.6 Construction real estate: Pass $ 493.7 $ 735.3 $ 331.2 $ 36.7 $ 16.8 $ 36.2 $ 104.4 $ 13.7 $ 1,768.0 Special mention 0.5 6.6 1.3 — — 0.2 — 0.9 9.5 Substandard 7.0 4.0 24.4 0.2 — 0.4 — — 36.0 Doubtful — 13.0 — — — — — — 13.0 Total $ 501.2 $ 758.9 $ 356.9 $ 36.9 $ 16.8 $ 36.8 $ 104.4 $ 14.6 $ 1,826.5 Current-period gross charge-offs — — 0.1 — 0.6 — — 9.6 10.3 Agricultural real estate: Pass $ 86.2 $ 123.7 $ 126.2 $ 93.5 $ 56.7 $ 124.3 $ 31.8 $ 7.0 $ 649.4 Special mention 2.6 9.5 3.5 1.9 1.5 11.3 0.5 — 30.8 Substandard 8.1 20.8 3.6 2.6 0.4 1.1 — — 36.6 Total $ 96.9 $ 154.0 $ 133.3 $ 98.0 $ 58.6 $ 136.7 $ 32.3 $ 7.0 $ 716.8 Current-period gross charge-offs — — — — — — — — — Commercial: Pass $ 481.6 $ 507.7 $ 389.8 $ 215.1 $ 108.7 $ 272.9 $ 762.3 $ 7.6 $ 2,745.7 Special mention 7.3 4.7 6.6 3.1 0.9 1.9 14.8 0.2 39.5 Substandard 15.8 19.6 9.0 7.0 1.6 3.0 58.8 0.4 115.2 Doubtful 3.3 1.3 1.6 — — 0.1 0.1 — 6.4 Total $ 508.0 $ 533.3 $ 407.0 $ 225.2 $ 111.2 $ 277.9 $ 836.0 $ 8.2 $ 2,906.8 Current-period gross charge-offs 0.2 0.4 0.5 0.5 0.2 0.1 1.4 0.1 3.4 Agricultural: Pass $ 105.7 $ 57.7 $ 31.6 $ 22.4 $ 6.1 $ 7.2 $ 421.9 $ 3.4 $ 656.0 Special mention 2.6 0.8 0.5 0.2 0.1 0.1 9.0 3.1 16.4 Substandard 43.8 0.3 2.7 0.7 28.8 2.2 18.5 — 97.0 Total $ 152.1 $ 58.8 $ 34.8 $ 23.3 $ 35.0 $ 9.5 $ 449.4 $ 6.5 $ 769.4 Current-period gross charge-offs — — — — — — — — — December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Commercial real estate non-owner occupied: Pass $ 1,162.6 $ 861.3 $ 661.1 $ 467.6 $ 241.5 $ 890.4 $ 29.2 $ 4,313.7 Special mention 1.0 6.8 2.3 4.6 — 7.4 — 22.1 Substandard 0.1 13.9 10.8 18.2 19.6 9.8 — 72.4 Total $ 1,163.7 $ 882.0 $ 674.2 $ 490.4 $ 261.1 $ 907.6 $ 29.2 $ 4,408.2 Commercial real estate owner occupied: Pass $ 793.0 $ 718.7 $ 533.9 $ 266.3 $ 165.8 $ 551.3 $ 18.2 $ 3,047.2 Special mention 10.9 14.2 12.3 6.1 5.6 5.5 1.1 55.7 Substandard 8.4 3.0 2.3 8.9 8.5 17.2 0.5 48.8 Doubtful 0.4 1.4 — — — — — 1.8 Total $ 812.7 $ 737.3 $ 548.5 $ 281.3 $ 179.9 $ 574.0 $ 19.8 $ 3,153.5 Commercial multi-family: Pass $ 369.2 $ 204.9 $ 189.0 $ 52.1 $ 35.0 $ 113.7 $ 1.0 $ 964.9 Special mention — — — — — 1.7 — 1.7 Substandard — — — — — 0.3 — 0.3 Total $ 369.2 $ 204.9 $ 189.0 $ 52.1 $ 35.0 $ 115.7 $ 1.0 $ 966.9 Land, acquisition and development: Pass $ 152.5 $ 114.4 $ 29.5 $ 17.0 $ 10.9 $ 28.4 $ 22.2 $ 374.9 Special mention 6.7 — — — 0.2 0.3 — 7.2 Substandard — 0.3 0.2 — — 0.4 — 0.9 Doubtful — 3.2 — — — — — 3.2 Total $ 159.2 $ 117.9 $ 29.7 $ 17.0 $ 11.1 $ 29.1 $ 22.2 $ 386.2 Residential construction: Pass $ 118.4 $ 119.9 $ 0.4 $ 0.3 $ 0.4 $ 5.8 $ 270.1 $ 515.3 Substandard — 0.5 — — — 0.4 — 0.9 Total $ 118.4 $ 120.4 $ 0.4 $ 0.3 $ 0.4 $ 6.2 $ 270.1 $ 516.2 Commercial construction: Pass $ 442.7 $ 374.8 $ 89.7 $ 45.9 $ 0.4 $ — $ 10.6 $ 964.1 Special mention 2.3 — 23.1 — — — 11.3 36.7 Substandard 16.8 24.4 — — — — — 41.2 Total $ 461.8 $ 399.2 $ 112.8 $ 45.9 $ 0.4 $ — $ 21.9 $ 1,042.0 Agricultural real estate: Pass $ 180.0 $ 172.8 $ 109.5 $ 64.8 $ 46.6 $ 105.1 $ 31.4 $ 710.2 Special mention 22.4 0.7 1.2 2.6 10.0 3.2 11.0 51.1 Substandard 1.8 12.3 3.5 0.6 2.7 11.3 0.1 32.3 Doubtful — — 1.3 — — — — 1.3 Total $ 204.2 $ 185.8 $ 115.5 $ 68.0 $ 59.3 $ 119.6 $ 42.5 $ 794.9 Commercial and floor plans: Pass $ 501.7 $ 358.9 $ 214.4 $ 124.3 $ 120.3 $ 171.1 $ 631.6 $ 2,122.3 Special mention 15.9 6.8 1.3 4.4 0.9 4.9 18.5 52.7 Substandard 9.8 3.3 3.7 3.4 3.2 2.1 47.2 72.7 Doubtful 0.3 1.3 — — — — 0.1 1.7 Total $ 527.7 $ 370.3 $ 219.4 $ 132.1 $ 124.4 $ 178.1 $ 697.4 $ 2,249.4 December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Commercial purpose secured by 1-4 family: Pass $ 191.7 $ 134.5 $ 69.8 $ 30.4 $ 29.9 $ 39.5 $ 28.9 $ 524.7 Special mention 0.1 1.2 2.1 0.2 1.4 0.2 — 5.2 Substandard 0.2 0.3 0.1 0.3 0.9 1.2 — 3.0 Total $ 192.0 $ 136.0 $ 72.0 $ 30.9 $ 32.2 $ 40.9 $ 28.9 $ 532.9 Agricultural: Pass $ 127.2 $ 59.7 $ 31.8 $ 10.6 $ 8.6 $ 3.1 $ 375.1 $ 616.1 Special mention 26.1 2.8 0.4 1.0 0.3 — 26.2 56.8 Substandard 22.8 4.6 2.8 0.6 1.2 0.2 0.8 33.0 Doubtful — 0.5 — — — — — 0.5 Total $ 176.1 $ 67.6 $ 35.0 $ 12.2 $ 10.1 $ 3.3 $ 402.1 $ 706.4 The Company evaluates the credit quality, loan performance, and the allowance for credit losses of its residential and consumer loan portfolios based primarily on the aging status of the loan and borrower payment activity. Accordingly, loans on nonaccrual status, loans past due 90 days or more and still accruing interest are considered nonperforming for purposes of credit quality evaluation. The following tables present the recorded investment of these loan portfolios based on the credit risk profile of loans that are performing and loans that are nonperforming as of the periods indicated: December 31, 2023 As of December 31, 2023 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2023 2022 2021 2020 2019 Prior Revolving Loans Amortized Cost Basis Revolving Loans Converted To Term Total Residential: Performing $ 44.7 $ 356.9 $ 521.3 $ 500.6 $ 88.5 $ 217.1 $ 471.8 $ 32.1 $ 2,233.0 Nonperforming 1.1 2.1 1.2 1.1 0.7 5.1 — — 11.3 Total $ 45.8 $ 359.0 $ 522.5 $ 501.7 $ 89.2 $ 222.2 $ 471.8 $ 32.1 $ 2,244.3 Current-period gross charge-offs 0.3 — 0.1 0.1 — 0.1 — — 0.6 Consumer indirect: Performing $ 194.9 $ 264.7 $ 115.4 $ 81.1 $ 32.9 $ 48.8 $ — $ — $ 737.8 Nonperforming 0.4 0.9 0.6 0.4 0.2 0.6 — — 3.1 Total $ 195.3 $ 265.6 $ 116.0 $ 81.5 $ 33.1 $ 49.4 $ — $ — $ 740.9 Current-period gross charge-offs 0.5 3.2 1.8 0.8 0.3 0.7 — — 7.3 Consumer direct and advance lines: Performing $ 44.5 $ 32.9 $ 18.5 $ 9.4 $ 3.6 $ 6.0 $ 26.2 $ 0.2 $ 141.3 Nonperforming 0.1 0.1 0.1 — — — — — 0.3 Total $ 44.6 $ 33.0 $ 18.6 $ 9.4 $ 3.6 $ 6.0 $ 26.2 $ 0.2 $ 141.6 Current-period gross charge-offs 0.2 0.5 0.2 0.4 0.1 2.6 0.1 — 4.1 Consumer credit card: Performing $ — $ — $ — $ — $ — $ — $ 75.9 $ — $ 75.9 Nonperforming — — — — — — 0.6 — 0.6 Total $ — $ — $ — $ — $ — $ — $ 76.5 $ — $ 76.5 Current-period gross charge-offs — — — — — — 2.6 — 2.6 As of December 31, 2022 Term Loans Amortized Cost Basis by Origination Year Risk by Collateral 2022 2021 2020 2019 2018 Prior Revolving Loans Amortized Cost Basis Total Residential 1-4 family: Performing $ 258.9 $ 490.3 $ 541.6 $ 98.0 $ 32.0 $ 213.8 $ — $ 1,634.6 Nonperforming — 0.2 0.1 0.5 0.3 3.7 — 4.8 Total $ 258.9 $ 490.5 $ 541.7 $ 98.5 $ 32.3 $ 217.5 $ — $ 1,639.4 Consumer home equity and HELOC: Performing $ 23.8 $ 8.0 $ 5.2 $ 5.5 $ 5.6 $ 15.2 $ 482.8 $ 546.1 Nonperforming 0.6 0.3 0.2 0.2 0.1 1.2 0.2 2.8 Total $ 24.4 $ 8.3 $ 5.4 $ 5.7 $ 5.7 $ 16.4 $ 483.0 $ 548.9 Consumer indirect: Performing $ 380.3 $ 176.4 $ 130.0 $ 59.7 $ 33.6 $ 46.3 $ — $ 826.3 Nonperforming 1.0 0.9 0.6 0.3 0.2 0.4 — 3.4 Total $ 381.3 $ 177.3 $ 130.6 $ 60.0 $ 33.8 $ 46.7 $ — $ 829.7 Consumer direct and advance lines: Performing $ 52.6 $ 31.9 $ 18.2 $ 8.5 $ 6.5 $ 8.9 $ 25.8 $ 152.4 Nonperforming 0.1 0.1 0.1 — — 0.1 0.1 0.5 Total $ 52.7 $ 32.0 $ 18.3 $ 8.5 $ 6.5 $ 9.0 $ 25.9 $ 152.9 While the Company considers the performance of the loan portfolio on the allowance for credit losses, for certain credit card loan classes, the Company also evaluates credit quality based on the aging status of the loan, which was previously presented, and by payment activity of the credit card holder. The following table presents the recorded investment in credit card loans based on payment activity for the periods indicated: As of December 31, 2022 Consumer Commercial Agricultural Total Credit Card: Performing $ 75.4 $ 100.0 $ 1.9 $ 177.3 Nonperforming 0.5 0.3 — 0.8 Total credit card $ 75.9 $ 100.3 $ 1.9 $ 178.1

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Premises and Equipment	PREMISES AND EQUIPMENT Premises and equipment and related accumulated depreciation are as follows: December 31, 2023 2022 Land $ 87.7 $ 86.7 Buildings and improvements 474.2 469.2 Furniture and equipment 111.6 111.0 Total premises and equipment 673.5 666.9 Less accumulated depreciation (229.2) (222.2) Premises and equipment, net $ 444.3 $ 444.7 Depreciation expense was $34.3 million, $35.1 million, and $28.0 million for the years ended December 31, 2023, 2022, and 2021, respectively. The Parent Company and a FIB branch office lease premises from an affiliated entity. See Note —Commitments and Contingencies.

Company-Owned Life Insurance

Company-Owned Life Insurance	12 Months Ended
	Dec. 31, 2023
Investments, All Other Investments [Abstract]
Company-Owned Life Insurance	COMPANY-OWNED LIFE INSURANCE Company-owned life insurance consists of the following: December 31, 2023 2022 Key executive, principal shareholder $ 1.8 $ 3.2 Key executive split dollar 5.0 7.1 Group life 495.6 487.6 Total $ 502.4 $ 497.9 The Company maintains key executive life insurance policies on certain principal shareholders. Under these policies, the Company receives benefits payable upon the death of the insured. The net cash surrender value of key executive, principal shareholder insurance policies was $1.8 million and $3.2 million at December 31, 2023 and 2022, respectively. The Company also has life insurance policies covering selected other key officers. The net cash surrender value of these policies was $5.0 million and $7.1 million at December 31, 2023 and 2022, respectively. Under these policies, the Company receives benefits payable upon death of the insured. An endorsement split dollar agreement has been executed with the selected key officers whereby a portion of the policy death benefit is payable to their designated beneficiaries. The endorsement split dollar agreement will provide post-retirement coverage for those selected key officers meeting specified retirement qualifications. The Company expenses the earned portion of the post-employment benefit through the vesting period.

Other Real Estate Owned

Other Real Estate Owned	12 Months Ended
	Dec. 31, 2023
Repossessed Assets [Abstract]
Other Real Estate Owned	Information with respect to the Company’s other real estate owned follows: Year Ended December 31, 2023 2022 2021 Balance at beginning of year $ 12.7 $ 2.0 $ 2.5 Acquired through acquisitions — 15.8 — Additions 8.3 0.4 0.9 Valuation adjustments (1.1) (2.8) — Dispositions (3.4) (2.7) (1.4) Balance at end of year $ 16.5 $ 12.7 $ 2.0 There were $1.1 million and $2.8 million of valuation adjustments at December 31, 2023 and 2022, respectively, which were adjustments based on internal evaluations and other sources, including management estimates of the current fair value of properties, and adjustments directly related to receipt of updated appraisals. There were no material valuation adjustments during 2021. The carrying value of foreclosed residential real estate properties included in OREO was not material as of December 31, 2023 and 2022. The Company had $0.5 million material recorded investments in consumer mortgage loans secured by residential real estate for which formal foreclosure proceedings were in process of foreclosure as of December 31, 2023. The Company had no material recorded investments in consumer mortgage loans secured by residential real estate for which formal foreclosure proceedings were in process of foreclosure as of December 31, 2022.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	12 Months Ended
	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	DERIVATIVES AND HEDGING ACTIVITIES The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through the management of its business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its assets and liabilities and derivative financial instruments. The Company enters into derivative financial instruments, such as interest rate swap contracts to manage or hedge exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates and interest rate exposures. The Company does not enter into interest rate swap agreements for trading or speculative purposes. The Company sells residential mortgage loans on either a best efforts or mandatory delivery basis. The Company mitigates the effect of the interest rate risk inherent in providing interest rate lock commitments by entering into forward loan sales contracts. The forward loan sales contracts are recorded at fair value with changes in fair value recorded through earnings and are not designated as accounting hedges. Exclusive of the fair value component associated with the projected cash flows from the loan delivery to the investor, the changes in fair value related to movements in market rates of the interest rate lock commitments and the forward loan sales contracts generally move in opposite directions, and the net impact of changes in these valuations on net income during the loan commitment period is generally inconsequential. When the loan is funded to the borrower, the interest rate lock commitment derivative expires, and the Company records a loan held for sale. The forward loan sales contract acts as a hedge against the variability in cash to be received from the loan sale. The changes in measurement of the estimated fair values of the interest rate lock commitments and forward loan sales contracts are included in mortgage banking revenues in the accompanying consolidated statements of income (loss). The Company also enters into certain interest rate swap contracts that are not designated as hedging instruments. These derivative contracts relate to transactions in which the Company enters into an interest rate swap with a client while at the same time entering into an offsetting interest rate swap with a third-party financial institution. Because the Company acts as an intermediary for the client, changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact the Company’s results of operations. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest income (expense) and to manage its exposure to interest rate movements. To accomplish these objectives, the Company primarily uses interest rate swaps and collars as part of its interest rate risk management strategy. As part of the Company’s overall asset and liability management strategy, in August 2022 the Company entered into two interest rate collars related to variable-rate loans that were designated as cash flow hedges with a total notional amount of $300.0 million. Each of the collars designated as cash flow hedges synthetically fixes the interest income received by the Company when the collar index falls below a floor rate on a rate reset during the term of the collar and when the collar index exceeds the cap rate on a rate reset during the term of the collar without exchange of the underlying notional amount. In October 2022, the Company entered into four swaps, two of which were related to variable-rate loans and two that were related to variable-rate securities that were designated as cash flow hedges with a total notional amount of $850.0 million. Each of these swaps designated as cash flow hedges synthetically fixes the interest income received by the Company without exchange of the underlying notional amount. Of the six trades with a total notional amount of $1.15 billion, five are effective with a total notional of $900.0 million. Of these effective trades, the two collars and one swap are related to variable-rate loans and the other two swaps are related to variable-rate securities. For derivatives that are designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in accumulated other comprehensive income and subsequently reclassified into interest income (expense) in the same period(s) during which the hedged transaction affects earnings. Amounts reported in accumulated other comprehensive income related to derivatives will be reclassified as interest income (expense) when interest payments are made on the Company’s variable-rate liabilities. During the next twelve months, based on implied forward curves, the Company estimates that $9.1 million will be reclassified as an increase to interest expense. Fair Value Hedges of Interest Rate Risk The Company is exposed to changes in the fair value of fixed-rate assets due to changes in benchmark interest rates. The Company uses interest rate swaps to manage its exposure to changes in fair value on these instruments attributable to changes in the designated benchmark interest rate. Interest rate swaps designated as fair value hedges involve the payment of fixed-rate amounts to a counterparty in exchange for the Company receiving variable-rate payments over the life of the agreements without the exchange of the underlying notional amount. During the second quarter of 2022, the Company terminated the $500.0 million, two-year forward starting, three-year pay-fixed interest rate swap, resulting in a $23.3 million gain. The gain associated with the $500.0 million interest rate swap was to be accreted into income through May 2026. However, the U.S. Treasury securities associated with the swap were sold during the fourth quarter of 2022. As such, the gain was accreted through August 2022 and then in September 2022 the remaining gain was recognized as income. During the third quarter of 2022, the Company terminated the $200.0 million, three-year forward starting, four-year pay fixed interest rate swap, resulting in a $8.5 million gain that will be accreted into income through July 2028. The Company accreted $1.4 million of the gain into interest income during the period ended December 31, 2023. For derivatives designated and that qualify as fair value hedges, the gain or loss on the derivative as well as the offsetting loss or gain on the hedged item attributable to the hedged risk are recognized in interest income. The following amounts were recorded on the consolidated balance sheets related to cumulative basis adjustment for fair value hedges for the periods indicated: December 31, 2023 December 31, 2022 Carrying Amount of the Hedged Assets/(Liabilities) Cumulative Amount of Fair Value Hedging Adjustment Carrying Amount of the Hedged Assets/(Liabilities) Cumulative Amount of Fair Value Hedging Adjustment Available-for-sale securities $ 193.3 $ 6.7 $ 191.9 $ 8.1 Non-designated Hedge Derivatives Derivatives not designated as accounting hedges are not speculative and result from a service the Company provides to certain customers. The Company executes interest rate swaps with commercial banking customers to facilitate their respective risk management strategies. Those interest rate swaps are simultaneously hedged by offsetting derivatives that the Company executes with a third party, such that the Company minimizes its net risk exposure resulting from such transactions. As the interest rate derivatives associated with this program do not meet the strict hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings. Risk Participation Agreements The Company acquired from GWB risk participation agreements under which it assumes credit risk associated with a borrower’s performance related to derivative contracts. The Company only entered into these credit risk participation agreements in instances in which the Company was also a party to the related loan participation agreements for such borrowers. The Company manages its credit risk under risk participation agreements by monitoring the creditworthiness of the borrower, based on its normal credit review process. The following table summarizes the fair values of our derivative instruments on a gross and net basis for the periods indicated. The derivative asset and liability balances are presented on a gross basis, prior to the application of bilateral collateral and master netting agreements, but after the variation margin payments with central clearing organizations have been applied as settlement, as applicable. Total derivative assets and liabilities are adjusted to account for the impact of legally enforceable master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Securities collateral related to legally enforceable master netting agreements is not offset on the consolidated balance sheets. December 31, 2023 December 31, 2022 Notional Amount Consolidated Balance Sheet Location Estimated Notional Amount Consolidated Balance Sheet Location Estimated Derivatives designated as accounting hedges: Interest rate swap contracts $ 550.0 $ 3.0 $ 550.0 $ 3.5 Derivatives not designated as accounting hedges: Interest rate swap contracts 1,589.0 34.3 1,728.1 41.6 Interest rate lock commitments 5.7 0.1 — — Forward loan sales contracts — — 12.6 0.1 Derivative assets $ 2,144.7 Other assets $ 37.4 $ 2,290.7 Other assets $ 45.2 Derivatives designated as accounting hedges: Interest rate collars $ 300.0 $ 3.6 $ 300.0 $ 5.4 Interest rate swap contracts 300.0 2.4 300.0 0.3 Derivatives not designated as accounting hedges: Interest rate swap contracts 1,589.0 121.1 1,728.1 153.9 Risk participation agreements 101.1 0.1 106.1 — Interest rate lock commitments — — 14.8 — Forward loan sales contracts 5.6 0.1 — — Derivative liabilities $ 2,295.7 Accounts payable and accrued expenses $ 127.3 $ 2,449.0 Accounts payable and accrued expenses $ 159.6 There was an unrealized fair value loss on cash flow hedging derivative instruments in accumulated other comprehensive income of $6.5 million during the period ended December 31, 2023. There were $2.2 million of derivative instruments in fair value or cash flow hedge accounting on accumulated other comprehensive loss during the period ended December 31, 2022. There was a loss of $7.5 million reclassified from accumulated other comprehensive loss into the consolidated statements of income during the period ended December 31, 2023 from the Company’s fair value or cash flow hedged derivative financial instruments. There were no material amounts reclassified during the comparable 2022 period. The table below presents the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the consolidated statements of income for the periods indicated: December 31, 2023 2022 Location of Loss Recognized in Income on Derivatives Amount of Loss Recognized in Income on Derivatives Interest rate lock commitments Mortgage banking revenues $ (0.1) $ (1.7) The Company recorded swap fee revenues of $0.7 million and $5.9 million for the years ended December 31, 2023 and 2022, respectively. The Company includes swap fee revenues in other service charges, commissions, and fees on the consolidated statements of income. The tables below present the gross presentation, the effects of offsetting, and a net presentation of the Company’s derivatives as of the dates indicated: December 31, 2023 Gross Assets Recognized Gross Assets Offset in the Balance Sheet Net Assets in the Balance Sheet Financial Instruments Cash Collateral Received (1) Net Amount Interest rate swap contracts $ 37.3 $ — $ 37.3 $ — $ 32.7 $ 4.6 Interest rate lock commitments 0.1 — 0.1 — — 0.1 Total derivatives 37.4 — 37.4 — 32.7 4.7 Total assets $ 37.4 $ — $ 37.4 $ — $ 32.7 $ 4.7 (1) Netting adjustments represent the amounts recorded to convert derivatives assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The application of the collateral cannot reduce the net derivative position below zero. Therefore, excess collateral, if any, is not reflected above. Gross Liabilities Recognized Gross Liabilities Offset in the Balance Sheet Net Liabilities in the Balance Sheet Financial Instruments Cash Collateral Posted Net Amount Interest rate swap and collar contracts $ 127.1 $ — $ 127.1 $ — $ — $ 127.1 Risk participation agreements 0.1 — 0.1 — — 0.1 Forward loan sales contracts 0.1 — 0.1 — — 0.1 Total derivatives 127.3 — 127.3 — — 127.3 Repurchase agreements 782.7 — 782.7 — 782.7 — Total liabilities $ 910.0 $ — $ 910.0 $ — $ 782.7 $ 127.3 December 31, 2022 Gross Assets Recognized Gross Assets Offset in the Balance Sheet Net Assets in the Balance Sheet Financial Instruments Cash Collateral Received (1) Net Amount Interest rate swap contracts $ 45.1 $ — $ 45.1 $ — $ 45.1 $ — Mortgage related derivatives 0.1 — 0.1 — — 0.1 Total derivatives 45.2 — 45.2 — 45.1 0.1 Total assets $ 45.2 $ — $ 45.2 $ — $ 45.1 $ 0.1 Gross Liabilities Recognized Gross Liabilities Offset in the Balance Sheet Net Liabilities in the Balance Sheet Financial Instruments Cash Collateral Posted Net Amount Interest rate swap contracts $ 159.6 $ — $ 159.6 $ — $ — $ 159.6 Total derivatives 159.6 — 159.6 — — 159.6 Repurchase agreements 1,052.9 — 1,052.9 — 1,052.9 — Total liabilities $ 1,212.5 $ — $ 1,212.5 $ — $ 1,052.9 $ 159.6 (1) Netting adjustments represent the amounts recorded to convert derivatives assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The application of the collateral cannot reduce the net derivative position below zero. Therefore, excess collateral, if any, is not reflected above. Credit-risk-related Contingent Feature The Company has agreements with each of its derivative counterparties that contain a provision where if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. The company has agreements with each of its derivative counterparties that contain a provision where the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company's default on the indebtedness. The Company has agreements with certain of its derivative counterparties that contain a provision where if the Company fails to maintain its status as a well / adequately capitalized institution, then the counterparty could terminate the derivative positions and the Bank would be required to settle its obligations. Similarly, the Bank could be required to settle its obligations under certain of its agreements if specific regulatory events occur, such as a publicly issued prompt corrective action directive, cease and desist order, or a capital maintenance agreement that required the Bank to maintain a specific capital level. If the Bank had breached any of these provisions at December 31, 2023 or 2022, it could have been required to settle its obligations under the agreements at the termination value. As of December 31, 2023, the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, was zero related to these agreements. As of December 31, 2023, the Company has minimum collateral posting thresholds with certain of its derivative counterparties and has not posted excess collateral. If the Company had breached any of these provisions at December 31, 2023, it could have been required to settle its obligations under the agreements at their termination value.

Mortgage Servicing Rights

Mortgage Servicing Rights	12 Months Ended
	Dec. 31, 2023
Transfers and Servicing [Abstract]
Mortgage Servicing Rights	MORTGAGE SERVICING RIGHTS Information with respect to the Company’s mortgage servicing rights follows: Year Ended December 31, 2023 2022 2021 Balance at beginning of year $ 31.1 $ 31.6 $ 34.3 Acquisition of mortgage servicing rights — 1.3 — Originations of mortgage servicing rights 1.1 2.5 3.7 Amortization expense (3.9) (4.3) (6.4) Balance at end of year 28.3 31.1 31.6 Less valuation reserve — — (3.4) Balance at end of year, net of valuation reserve $ 28.3 $ 31.1 $ 28.2 Principal balance of serviced loans underlying mortgage servicing rights $ 3,091.1 $ 3,259.8 $ 3,203.7 Mortgage servicing rights as a percentage of serviced loans 0.92 % 0.95 % 0.88 %

Deposits

Deposits	12 Months Ended
	Dec. 31, 2023
Deposits [Abstract]
Deposits	DEPOSITS Deposits are summarized as follows: December 31, 2023 2022 Non-interest bearing demand $ 6,029.6 $ 7,560.0 Interest bearing: Demand 6,507.8 7,205.9 Savings 7,775.8 8,379.3 Time, $250 and over 811.6 438.0 Time, other 2,198.3 1,490.4 Total interest bearing 17,293.5 17,513.6 Total deposits $ 23,323.1 $ 25,073.6 Other time deposits include time deposits under $250,000 and deposits obtained through the Company’s participation in the Certificate of Deposit Account Registry Service (“CDARS”). CDARS deposits totaled $26.6 million and $36.6 million as of December 31, 2023 and 2022, respectively. The Company had no brokered deposits as of December 31, 2023 and $12.5 million of brokered deposits as of December 31, 2022. As of December 31, 2023 and 2022, the Company had time deposits of $811.6 million and $438.0 million, respectively, that met or exceeded the FDIC insurance limit of $250,000. Maturities of time deposits at December 31, 2023 are as follows: Time, $250 Total Time Due within 3 months or less $ 219.7 $ 770.4 Due after 3 months and within 6 months 233.9 854.0 Due after 6 months and within 12 months 279.5 1,024.3 Due within 2025 62.8 277.1 Due within 2026 9.1 48.2 Due within 2027 4.9 28.4 Due within 2028 and thereafter 1.7 7.5 Total $ 811.6 $ 3,009.9

Long-Term Debt and Other Borrow

Long-Term Debt and Other Borrowed Funds	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Long-Term Debt and Other Borrowed Funds	LONG-TERM DEBT AND OTHER BORROWED FUNDS A summary of long-term debt follows: December 31, 2023 2022 Parent Company: Fixed to floating subordinated notes, 5.25% fixed rate effective May 2020 through May 2025 $ 99.0 $ 98.9 Subsidiaries: 8.00% finance lease obligation with term ending October 31, 2029 0.9 1.0 1.00% note payable maturing December 31, 2041, interest only payable quarterly until September 30, 2024 and then principal and interest until maturity 5.1 5.1 Note payable maturing March 31, 2038, interest only payable at 1.30% monthly until March 31, 2025 and then principal and interest at 3.25% until maturity 2.0 2.0 1.30% note payable maturing June 1, 2034, interest only payable monthly until March 31, 2025 and then principal and interest until maturity 0.6 0.6 1.12% note payable maturing December 31, 2045, interest only payable annually until December 31, 2028 and then principal and interest until maturity 6.8 6.8 1.35% note payable maturing December 31, 2046 interest only payable annually until December 31, 2025 and then principal and interest until maturity 6.4 6.4 Total long-term debt $ 120.8 $ 120.8 Maturities of long-term debt at December 31, 2023 were as follows: 2024 $ 0.1 2025 0.1 2026 0.1 2027 0.2 2028 0.2 Thereafter 120.1 Total $ 120.8 On May 15, 2020, the Company completed a public offering of $100.0 million fixed-to-floating rate subordinated notes due May 15, 2030 (the “Notes”). The debt is included in Tier 2 capital for the Company. The Company may elect to redeem the Notes, in whole or in part, on any early redemption date which is any interest payment date on or after May 15, 2025 at a redemption price equal to 100% of the principal amount plus any accrued and unpaid interest. The Company may also redeem the Notes, in whole but not in part, upon certain conditions as defined in the indenture agreement. Any early redemption of the Notes will be subject to regulatory approval. From and including the date of issuance to, but excluding, May 15, 2025, or earlier redemption date, the Notes bear interest at an initial fixed rate of 5.25% per annum, payable semi-annually in arrears on May 15 and November 15 of each year, which commenced on November 15, 2020. From and including May 15, 2025 to, but excluding, May 15, 2025, or earlier redemption date, the Notes will bear interest at a floating rate per annum equal to a benchmark rate, which is expected to be Three-Month Term Secured Overnight Financing Rate (“SOFR”) (as defined in the First Supplemental Indenture Agreement), plus 518.0 basis points, payable quarterly in arrears on February 15, May 15, August 15 and November 15 of each year, commencing on August 15, 2025. Unamortized debt issuance costs of $1.0 million, as of December 31, 2023, are being amortized to maturity. Subordinated debt is presented net of issuance costs on the consolidated balance sheet. The Notes are unsecured, subordinated obligations of the Company and: (i) rank junior to all of the Company’s existing and future senior indebtedness; (ii) rank equal in right of payment with any of the Company’s existing and future subordinated indebtedness; (iii) rank senior to the Company’s obligations relating to any junior subordinated debt securities issued to its capital trust subsidiaries; (iv) are effectively subordinated to all of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and (v) are structurally subordinated to all of the existing and future liabilities and obligations of the Company’s subsidiaries, including deposit liabilities and claims of other creditors of the Company’s bank subsidiary, First Interstate Bank. Proceeds from the private placement of subordinated notes were used for general corporate purposes. The Company has a financing lease obligation on a banking office. Assets acquired under the financing lease, consist solely of a building and leasehold improvements, and are included in premises and equipment subject to depreciation. Additionally, the Company borrowed or assumed through acquisitions $20.9 million and $20.9 million as of December 31, 2023 and 2022, respectively, related to New Market Tax Credits. The long-term debt obligations consist of fixed rate note payables with various interest rates from 1.00% to 3.25% and maturities from September 6, 2032 through December 31, 2046, collateralized by the Company’s equity interest in various CDEs, which are 99.9% owned by the Company. At December 31, 2023, the Company had $2,603.0 million in outstanding FHLB borrowings, as compared to $2,327.0 million outstanding borrowings with the FHLB at December 31, 2022. At December 31, 2023, the Company has remaining available lines of credit with the FHLB of approximately $3,619.6 million, subject to collateral availability. The borrowings are collateralized by certain loans and securities with an advance equivalent collateral value of $6,222.6 million. As of December 31, 2023 and December 31, 2022, there were no long or short-term advances outstanding with the FHLB. As of December 31, 2023 and December 31, 2022, the Company had no other material outstanding borrowings classified as other borrowed funds. The following table presents outstanding FHLB borrowings by maturity buckets for the dates indicated: As of December 31, 2023 Average Rate Outstanding Balance Fixed rate borrowing with tenors of up to three-months 5.52 % $ 2,603.0 As of December 31, 2022 Rate Outstanding Balance Variable rate overnight borrowings 4.60 % $ 827.0 Fixed rate borrowings in tenors of up to one month 4.48 1,500.0 $ 2,327.0 The Company has unused federal fund lines of credit with third parties amounting to $235.0 million, subject to funds availability. These lines are subject to cancellation without notice. The Company also has an unused line of credit with the FRB for borrowings up to $3,039.5 million secured by a blanket pledge of agricultural and commercial loans, and has an unused $50.0 million revolving line of credit with another third party.

Subordinated Debentures Held by

Subordinated Debentures Held by Subsidiary Trusts	12 Months Ended
	Dec. 31, 2023
Subordinated Borrowings [Abstract]
Subordinated Debentures Held by Subsidiary Trusts	SUBORDINATED DEBENTURES HELD BY SUBSIDIARY TRUSTS The Company sponsors fourteen wholly owned business trusts, Trust I through Trust XIV (collectively, the “Trusts”). The Trusts were formed for the exclusive purpose of issuing an aggregate of $163.1 million of 30-year floating rate mandatorily redeemable capital trust preferred securities (“Trust Preferred Securities”) to third-party investors. The Trusts also issued, in aggregate, $5.3 million of common equity securities to the Parent Company. Proceeds from the issuance of the Trust Preferred Securities and common equity securities were invested in 30-year junior subordinated deferrable interest debentures (“Subordinated Debentures”) issued by the Parent Company. A summary of Subordinated Debenture issuances follows: December 31, 2023 December 31, 2022 Issuance Interest Rate 1 Maturity Date Amount Common Shares 2 Amount Common Shares 2 Trust I November 2007 8.40% December 15, 2037 $ 15.5 $ 0.5 $ 15.5 $ 0.5 Trust II October 2007 7.91 January 1, 2038 10.3 0.3 10.3 0.3 Trust III December 2007 8.05 December 15, 2037 20.6 0.6 20.6 0.6 Trust IV December 2007 8.36 April 1, 2038 15.5 0.5 15.5 0.5 Trust V January 2008 8.41 April 1, 2038 10.3 0.3 10.3 0.3 Trust VI January 2008 8.41 April 1, 2038 10.3 0.3 10.3 0.3 Trust VII June 2005 7.29 June 30, 2035 5.2 0.2 5.2 0.2 Trust VIII March 2006 7.13 March 15, 2036 30.9 0.9 30.9 0.9 Trust IX June 2005 7.50 June 15, 2035 2.1 0.1 2.1 0.1 Trust X December 2003 8.49 December 17, 2033 23.1 0.7 23.1 0.7 Trust XI December 2002 9.01 January 7, 2033 5.2 0.2 5.2 0.2 Trust XII September 2003 8.76 October 8, 2033 7.2 0.2 7.2 0.2 Trust XIII December 2006 7.47 March 1, 2037 5.3 0.3 5.3 0.3 Trust XIV July 2007 7.31 October 1, 2037 2.2 0.2 2.2 0.2 Total subordinated debentures payable 163.7 $ 5.3 163.7 $ 5.3 Less: fair value adjustment 3 (0.6) (0.6) Total subordinated debentures payable, net of fair value adjustments $ 163.1 $ 163.1 1 Interest rates as of December 31, 2023 2 Common shares on subordinated debentures are included in other assets on the consolidated balance sheets 3 Adjustment reflects the fair value adjustments related to the subordinated deferrable interest debentures assumed as part of the Northwest and Great Western acquisitions. Trust I Subordinated Debentures issued by the Company bore interest at a fixed rate of 7.50% for five years after issuance until December 15, 2012, and thereafter at a variable rate equal to three-month SOFR plus tenor spread plus 2.75% per annum. Interest payment dates are December 15, March 15, June 15, and September 15 of each year, beginning December 15, 2007, and are payable in arrears. Trust II Subordinated Debentures issued by the Company bear a cumulative floating interest rate equal to SOFR plus tenor spread plus 2.25% per annum. Interest payment dates are January 1, April 1, July 1 and October 1 of each year, beginning January 1, 2008, and are payable in arrears. Trust III Subordinated Debentures issued by the Company bore interest at a fixed rate of 6.88% for five years after issuance until December 15, 2012, and thereafter at a variable rate equal to three-month SOFR plus tenor spread plus 2.40% per annum. Interest payment dates are December 15, March 15, June 15, and September 15 of each year, beginning March 15, 2008, and are payable in arrears. Trust IV Subordinated Debentures issued by the Company bear a cumulative floating interest rate equal to three-month SOFR plus tenor spread plus 2.70% per annum. Interest payment dates are January 1, April 1, July 1 and October 1 of each year, beginning April 1, 2008, and are payable in arrears. Trust V Subordinated Debentures issued by the Company bore interest at a fixed rate of 6.78% for five years after issuance until April 1, 2013, and thereafter at a variable rate equal to three-month SOFR plus tenor spread plus 2.75% per annum. Interest payment dates are January 1, April 1, July 1 and October 1 of each year, beginning April 1, 2008, and are payable in arrears. Trust VI Subordinated Debentures issued by the Company bear a cumulative floating interest rate equal to three-month SOFR plus tenor spread plus 2.75% per annum. Interest payment dates are January 1, April 1, July 1 and October 1 of each year, beginning April 1, 2008, and are payable in arrears. The Subordinated Debentures are unsecured with interest distributions payable quarterly. The Company may defer the payment of interest at any time provided that the deferral period does not extend past the stated maturity. During any such deferral period, distributions on the Trust Preferred Securities will also be deferred and the Company’s ability to pay dividends on its common and preferred shares is restricted. The Subordinated Debentures may be redeemed, subject to approval by the FRB, at the Company’s option on or after five years from the date of issue, or at any time in the event of unfavorable changes in laws or regulations. Debt issuance costs consisting primarily of underwriting discounts and professional fees were capitalized and are being amortized through maturity to interest expense using the straight-line method, which approximates level yield. The terms of the Trust Preferred Securities are identical to those of the Subordinated Debentures. The Trust Preferred Securities are subject to mandatory redemption upon repayment of the Subordinated Debentures at their stated maturity dates or earlier redemption in an amount equal to their liquidation amount plus accumulated and unpaid distributions to the date of redemption. The Company guarantees the payment of distributions and payments for redemption or liquidation of the Trust Preferred Securities to the extent of funds held by the Trusts. In conjunction with the acquisition of Northwest in August 2018, the Company acquired Northwest Bancorporation Capital Trust I (“Trust VII”). The Northwest Trust was formed for the exclusive purpose of issuing an aggregate of $5.0 million of 30-year floating rate mandatorily redeemable capital trust preferred securities (“Northwest Trust Preferred Securities”) to third-party investors. The Trusts also issued, in aggregate, $0.2 million of common equity securities to Northwest. Proceeds from the issuance of the Trust Preferred Securities and common equity securities were invested in 30-year junior subordinated deferrable interest debentures (“Northwest Subordinated Debentures”) issued by Northwest. The Subordinated Debentures bore interest at a fixed rate of 5.95% for five years after issuance until June 30, 2010, and thereafter at a variable rate equal to SOFR plus tenor spread plus 1.70% per annum. Interest payment dates are December 30, March 30, June 30, and September 30 of each year, beginning September 30, 2005, and are payable in arrears. The Company acquired the GWB Capital Trust VI (“Trust VIII”) with the acquisition of Great Western in February 2022. Great Western caused to be issued 30,000 shares, $1,000 par value, or $30.0 million of preferred securities of Trust VIII on March 10, 2006, through a private placement. Trust VIII also issued, in aggregate, $0.9 million of common equity securities to Great Western. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 1.48%. Interest payment dates are December 15, March 15, June 15, and September 15 of each year, beginning June 15, 2006, and are payable in arrears. Proceeds from the issue were used for general corporate purposes including redemption of Great Western’s Preferred Securities of GWB Capital Trust II. The Company acquired the Sunstate Banchares Trust II (Trust IX”) with the acquisition of Great Western in February 2022. Sunstate Bancshares caused to be issued 2,000 shares, $1,000 par value, or $2.0 million of preferred securities of Trust IX on June 1, 2005, through a private placement. Trust IX also issued, in aggregate, $0.1 million of common equity securities to Sunstate Banchsares. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 1.85%. Interest payment dates are March 15, June 15, September 15, and December 15 of each year, beginning September 15, 2005, and are payable in arrears. The Company acquired the Great Western Statutory Trust IV (“Trust X”) with the acquisition of Great Western in February 2022. Great Western caused to be issued 22,400 shares, $1,000 par value, or $22.4 million of preferred securities of Trust X on December 17, 2003, through a private placement. Trust X also issued, in aggregate, $0.7 million of common equity securities to Great Western. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 2.85% basis points. Interest payment dates are March 17, June 17, September 17 and December 17 of each year, beginning March 17, 2004 and are payable in arrears. Proceeds from the issue were used for general corporate purposes. The Company acquired the HF Financial Capital Trust III (“Trust XI”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 5,000 shares, $1,000 par value, or $5.0 million of preferred securities of Trust XI on December 19, 2002, through a private placement. Trust XI also issued, in aggregate, $0.2 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 3.35%. Interest payment dates are January 7, April 7, July 7, and October 7 of each year, beginning April 7, 2003, and are payable in arrears. The Company acquired the HF Trust IV (“Trust XII”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 7,000 shares, $1,000 par value, or $7.0 million of preferred securities of Trust XII on September 25, 2003, through a private placement. Trust XII also issued, in aggregate, $0.2 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 3.10%. Interest payment dates are January 8, April 8, July 8, and October 8 of each year, beginning January 8, 2004, and are payable in arrears. The Company acquired the HF Trust V (“Trust XIII”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 5,000 shares, $1,000 par value, or $5.0 million of preferred securities of Trust XIII on December 7, 2006, through a private placement. Trust XIII also issued, in aggregate, $0.3 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 1.83%. Interest payment dates are March 1, June 1, September 1, and December 1 of each year, beginning March 1, 2007, and are payable in arrears. In the first quarter of Great Western’s fiscal year 2017, Great Western redeemed 5,000 shares of Trust XIII debentures under the First Supplemental Indenture dated May 13, 2016. The Company acquired the HF Trust VI (“Trust XIV”) in the acquisition of Great Western in February 2022. HF Financial Corp. caused to be issued 2,000 shares, $1,000 par value, or $2.0 million of preferred securities of Trust XIV on July 5, 2007, through a private placement. Trust XIV also issued, in aggregate, $0.2 million of common equity securities to HF Financial Corp. The distribution rate is set quarterly at three-month SOFR plus tenor spread plus 1.65%. Interest payment dates are January 1, April 1, July 1, and October 1 of each year, beginning October 1, 2007, and are payable in arrears. For the seven Subordinated Debentures acquired from Great Western, the Company may, at one or more times, defer interest payments on the related debentures for up to 20 consecutive quarters following suspension of dividends on all capital stock. At the end of any deferral period, all accumulated and unpaid interest must be paid. Subject to the Company receiving prior approval of the Federal Reserve, if required, the Company has the right to redeem the debentures at the redemption price, in whole or in part, on an interest payment date. The redemption price is $1,000 per preferred security plus any accrued and unpaid interest to the date of redemption. Holders of the preferred securities have no voting rights. The preferred securities are unsecured and rank junior in priority of payment to all of the Company’s senior indebtedness and senior to the Company’s common and preferred stock. As of December 31, 2023, the Trust Preferred Securities qualified as tier 2 capital of the Parent Company under the Federal Reserve Board’s capital adequacy guidelines.

Capital Stock and Dividend Rest

Capital Stock and Dividend Restrictions	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Capital Stock and Dividend Restrictions	CAPITAL STOCK AND DIVIDEND RESTRICTIONS On May 24, 2023, the Company’s shareholders approved the proposed change of the Company’s state of incorporation from Montana to Delaware. At the effective time of the conversion, each outstanding share of the Company’s Class A common stock became an outstanding share of common stock of the Company and each outstanding option, warrant or other right to acquire shares of the Company’s previously designated Class A common stock became an outstanding option, warrant or other right to acquire shares of common stock of the Company. Accordingly, all references to Class A common stock in these financial statements and notes refer to the role of the Class A common stock in the GWB acquisition while all other references to the Company’s common capital stock have been retroactively changed to reference common stock. Until March 25, 2022, the Company’s authorized common stock had consisted of 250,000,000 shares, of which 150,000,000 shares were designated as Class A common stock and 100,000,000 were designated as Class B common stock. The Class A common stock had one vote per share while the class B common stock had five votes per share and was convertible to Class A common stock on a share-for-share basis. On March 24, 2022, the record date for our first annual stockholders’ meeting following the completion of the Great Western Bank (“GWB”) acquisition on February 1, 2022, all outstanding shares and rights to acquire shares of Class B common stock were automatically converted into the same number of outstanding shares and rights to acquire the same number of shares, as applicable, of Class A common stock. As a result, we now have only one class of common stock outstanding and issuable upon exercise of outstanding rights to acquire common stock, all with equivalent voting rights: namely, common stock. The Class A common stock is traded on the NASDAQ stock market, or NASDAQ, under the symbol “FIBK.” As of December 31, 2023, the Company is authorized to issue an aggregate of 150,100,000 shares of capital stock, of which, 150,000,000 shares are designated as common stock, and 100,000 are designated as preferred stock. Our common stock is uncertificated and has one vote per share. The Company had 103,941,626 and 104,442,023 shares of common stock outstanding as of December 31, 2023 and 2022, respectively, and no shares of preferred stock outstanding as of December 31, 2023 and 2022. During 2023, the Company issued 54,414 shares of its common stock to directors for their annual service on the Company's board of directors. The aggregate value of the shares issued to directors of $1.2 million is amortized into stock-based compensation expense in the accompanying consolidated statements of changes in stockholders’ equity over a one-year service based period. During 2022 and 2021, the Company issued 33,769 and 19,081 shares of its common stock with an aggregate value of $1.3 million and $0.9 million to directors for their service on the Company’s board of directors during 2022 and 2021, respectively. The aggregate value of the shares issued to directors is included in stock-based compensation expense in the accompanying consolidated statements of changes in stockholders’ equity. On February 1, 2022, the Company issued 46,879,601 shares of its Class A common stock with an aggregate value of approximately $1.7 billion as consideration for the acquisition of Great Western. On December 14, 2023, the Company completed the repurchase of one million shares of its common stock from the estate of a stockholder at a price of $32.14 per share, or the closing price per share of the common stock as reported on the Nasdaq Stock Market on December 14, 2023, representing an aggregate purchase price of $32.1 million. During 2022, the Company repurchased and retired the five million shares of common stock under it’s previously existing stock repurchase program. As of December 31, 2023, the Company did not have a repurchase program in effect. Other stock repurchases during 2023 and 2022 were redemptions of vested restricted shares tendered in lieu of cash for payment of income tax withholding amounts by participants in the Company’s equity compensation plans. On November 4, 2021, the Company filed a registration statement on Form S-4, as amended on December 14, 2021 with registration statement on Form S-4/A, to register 47,158,390 shares of Class A common stock to be issued as consideration for our acquisition of Great Western. On May 25, 2023, the Company filed a Registration Statement on Form S-8 to register an additional two million shares of common stock to be issued pursuant to the Company's 2023 Equity and Incentive Plan. On May 26, 2023, the Company filed a universal shelf registration statement on Form S-3, which was subsequently declared effective by the SEC. The shelf registration statement allows the Company to raise additional capital from time to time through offers and sales of registered securities consisting of debt securities, preferred stock, depository shares, common stock, warrants, purchase contracts, and units or units consisting of any combination of the foregoing securities. The Company may sell these securities using the prospectus in the shelf registration statement, together with applicable prospectus supplements, from time to time, in one or more offerings.

Earnings per Common Share

Earnings per Common Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings per Common Share	EARNINGS PER COMMON SHARE Basic earnings per common share is calculated by dividing net income by the weighted average number of common shares outstanding during the period presented, excluding unvested restricted stock. Diluted earnings per share is calculated by dividing net income by the weighted average number of common shares determined for the basic earnings per share computation plus the dilutive effects of stock-based compensation using the treasury stock method. The following table sets forth the computation of basic and diluted earnings per share for the periods presented: Year Ended December 31, 2023 2022 2021 Net income $ 257.5 $ 202.2 $ 192.1 Weighted average common shares outstanding for basic earnings per share computation 103,752,206 103,274,070 61,650,312 Dilutive effects of stock-based compensation 27,897 66,929 91,516 Weighted average common shares outstanding for diluted earnings per common share computation 103,780,103 103,340,999 61,741,828 Basic earnings per common share $ 2.48 $ 1.96 $ 3.12 Diluted earnings per common share 2.48 1.96 3.11 Anti-dilutive unvested time restricted stock 119,144 52,027 83,952

Regulatory Capital

Regulatory Capital	12 Months Ended
	Dec. 31, 2023
Banking Regulation, Risk-Based Information [Abstract]
Regulatory Capital	REGULATORY CAPITAL The Company and the Bank are subject to various regulatory capital requirements administered by federal banking regulators, including the Federal Reserve. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s and the Bank’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of the Company’s and Bank’s assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The Parent Company, like all bank holding companies, is not subject to the prompt corrective action provisions. The Company’s and the Bank’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. Quantitative measures established by regulation to ensure capital adequacy require the Company to maintain minimum amounts and ratios of total and tier 1 capital to risk-weighted assets, and of tier 1 capital to average assets, as defined in the regulations. As of December 31, 2023, the Company exceeded all capital adequacy requirements to which it is subject. As of December 31, 2023, the most recent notification from the regulatory agencies categorized the Bank as well capitalized under the regulatory framework for prompt corrective action. To be categorized as well-capitalized, the institution must maintain minimum total risk-based, Tier 1 risk-based, and Tier 1 leverage ratios as set forth in the following table. There are no conditions or events since the most recent notification that management believes have changed the Bank's categories. As an approved mortgage seller, the Bank is required to maintain a minimum level of capital specified by the United States Department of Housing and Urban Development. At December 31, 2023 and 2022, the Bank met these requirements. The Company’s actual capital amounts and ratios and selected minimum regulatory thresholds and prompt corrective action provisions as of December 31, 2023 and 2022 are presented in the following tables: Actual Minimum Required for Capital Adequacy Purposes For Capital Adequacy Purposes Plus Capital Conservation Buffer (1) Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements (2) December 31, 2023 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 2,941.1 13.28 % $ 1,771.6 8.00 % $ 2,325.2 10.50 % $ 2,214.5 10.00 % FIB 2,662.0 12.04 1,768.3 8.00 2,320.8 10.50 2,210.3 10.00 Tier 1 risk-based capital: Consolidated 2,454.4 11.08 1,328.7 6.00 1,882.3 8.50 1,771.6 8.00 FIB 2,433.0 11.01 1,326.2 6.00 1,878.8 8.50 1,768.3 8.00 Common equity tier 1 risk-based capital: Consolidated 2,454.4 11.08 996.5 4.50 1,550.1 7.00 1,439.4 6.50 FIB 2,433.0 11.01 994.6 4.50 1,547.2 7.00 1,436.7 6.50 Leverage capital ratio: Consolidated 2,454.4 8.22 1,193.9 4.00 1,193.9 4.00 1,492.3 5.00 FIB 2,433.0 8.16 1,192.2 4.00 1,192.2 4.00 1,490.2 5.00 December 31, 2022 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 2,875.8 12.48 % $ 1,843.2 8.00 % $ 2,419.2 10.50 % $ 2,304.0 10.00 % FIB 2,713.5 11.80 1,839.6 8.00 2,414.5 10.50 2,299.5 10.00 Tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,382.4 6.00 1,958.4 8.50 1,843.2 8.00 FIB 2,504.1 10.89 1,379.7 6.00 1,954.6 8.50 1,839.6 8.00 Common equity tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,036.8 4.50 1,612.8 7.00 1,497.6 6.50 FIB 2,504.1 10.89 1,034.8 4.50 1,609.7 7.00 1,494.7 6.50 Leverage capital ratio: Consolidated 2,408.8 7.75 1,242.9 4.00 1,242.9 4.00 1,553.6 5.00 FIB 2,504.1 8.07 1,241.1 4.00 1,241.1 4.00 1,551.4 5.00 (1) The capital conservation buffer is an additional 2.5% of the amount necessary to meet the minimum risk-based capital requirements for total, tier 1, and common equity tier 1 risk-based capital. (2) The ratios to meet the requirements to be deemed “well-capitalized” are only applicable to FIB. However, the Company manages its capital position as if the requirements apply to the consolidated company and has presented the ratios as if they also applied on a consolidated basis

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES The Company had commitments under construction contracts of $4.5 million as of December 31, 2023. The Parent Company and the Billings office of FIB are the anchor tenants in a building owned by an entity in which FIB has a 50.0% ownership interest. The Company leases certain premises and equipment from third parties under operating leases. Total rental expense to third parties was $9.3 million, $8.9 million, and $4.3 million, in 2023, 2022, and 2021, respectively. The total future minimum rental commitments, exclusive of maintenance and operating costs, required under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2023, are as follows: Third Parties Related Entity Total For the year ending December 31: 2024 $ 10.2 $ 1.4 $ 11.6 2025 8.5 1.4 9.9 2026 7.2 0.9 8.1 2027 5.4 0.1 5.5 2028 4.2 — 4.2 Thereafter 11.3 — 11.3 Total $ 46.8 $ 3.8 $ 50.6 Residential mortgage loans sold to investors in the secondary market are sold with varying recourse provisions. Essentially all the loan sales agreements require the repurchase of a mortgage loan by the seller in situations such as breach of representation, warranty, or covenant; untimely document delivery; false or misleading statements; failure to obtain certain certificates or insurance; or unmarketability. Certain loan sales agreements contain repurchase requirements based on payment-related defects that are defined in terms of the number of days or months since the purchase, the sequence number of the payment, and/or the number of days of payment delinquency. Based on the specific terms stated in the agreements, the Company had $0.8 million and $0.9 million of sold residential mortgage loans with recourse provisions still in effect as of December 31, 2023 and 2022, respectively. The Company did not repurchase a significant amount of loans from secondary market investors under the terms of loan sales agreements during the years ended December 31, 2023, 2022, and 2021. In the opinion of management, the risk of recourse and the subsequent requirement of loan repurchase to the Company is not significant, and accordingly no liabilities have been established related to such. In addition, the Company made various representations and warranties associated with the sale of loans. The Company has not incurred significant losses resulting from these provisions. A substantial portion of the Company’s clients’ ability to honor their contracts is dependent on the economy in Arizona, Colorado, Idaho, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, North Dakota, Oregon, South Dakota, Washington, and Wyoming. The Company’s loan portfolio is diversified and assigned to risk classifications by industry concentrations and the current economic conditions. These industry concentrations of credit are taken into consideration by management in determining the allowance for credit losses. In the normal course of business, the Company is involved in various other claims and litigation. In the opinion of management, following consultation with legal counsel, the ultimate liability or disposition thereof is not expected to have a material adverse effect on the consolidated financial condition, results of operations, or liquidity of the Company.

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk	12 Months Ended
	Dec. 31, 2023
Financial Instruments with Off-Balance Sheet Risk [Abstract]
Financial Instruments with Off-Balance Sheet Risk	FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK In the normal course of business, the Company is a party to financial instruments with off-balance sheet risk to meet the financing needs of its clients. These financial instruments include commitments to extend credit and standby letters of credit. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of amounts recorded in the consolidated balance sheets. Commitments to extend credit are agreements to lend to a client so long as there is no violation of any condition established in the commitment contract. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a client to a third party. The credit risk involved in issuing letters of credit is essentially the same as the credit risk involved in extending loan facilities to clients. The Company’s policy for obtaining collateral, and determining the nature of such collateral, is essentially the same as in the Company’s policies for making commitments to extend credit. The estimated fair value of the obligation undertaken by the Company in issuing standby letters of credit is included in accounts payable and accrued expenses in the Company’s consolidated balance sheets. The following table presents our financial instruments with off-balance sheet risk, as well as the activity in the allowance for off-balance sheet credit losses related to those financial instruments: December 31, December 31, Beginning balance $ 16.2 $ 3.8 Provision for credit loss expense 2.2 12.4 Ending balance $ 18.4 $ 16.2 December 31, December 31, Unused credit card lines $ 814.0 $ 827.6 Commitments to extend credit 4,069.2 5,173.3 Standby letters of credit 97.1 93.8

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income tax expense consists of the following: Year ended December 31, 2023 2022 2021 Current: Federal $ 46.1 $ 45.2 $ 39.4 State 12.8 14.4 11.3 Total current 58.9 59.6 50.7 Deferred: Federal 16.0 (3.7) 3.7 State 4.4 (1.0) 1.3 Total deferred 20.4 (4.7) 5.0 Total income tax expense $ 79.3 $ 54.9 $ 55.7 Total income tax provision differs from the amount of income tax determined by applying the statutory federal income tax rate of 21% for the periods presented to income before income taxes due to the following: Year ended December 31, 2023 2022 2021 Tax expense at the statutory tax rate $ 70.7 $ 54.0 $ 52.0 Increase (decrease) in tax resulting from: Tax-exempt income (8.1) (8.4) (2.8) State income tax, net of federal income tax benefit 13.6 10.6 9.9 Deficiency (benefit) of stock-based compensation plans 0.3 0.2 (0.5) Nondeductible transaction costs — 2.0 0.8 Federal tax credits (0.2) (4.3) (4.3) FDIC premiums 2.0 1.6 — Other, net 1.0 (0.8) 0.6 Tax expense at effective tax rate $ 79.3 $ 54.9 $ 55.7 The tax effects of temporary differences between the financial statement carrying amounts and tax bases of assets and liabilities that give rise to significant portions of the net deferred tax asset (liability) relate to the following: December 31, 2023 2022 Deferred tax assets: Loans, principally due to allowance for credit losses $ 56.7 $ 54.8 Loan discount 21.7 32.5 Investment securities, unrealized losses 118.1 157.9 Derivatives, unrealized losses 0.3 0.5 Deferred compensation 18.6 26.8 Non-performing loan interest 2.2 2.6 Other real estate owned write-downs and carrying costs 1.4 1.5 Net operating loss carryforwards (1) 1.1 1.5 Lease liabilities 11.0 12.0 Other reserves 10.7 8.8 Contract incentives 7.5 8.5 Discount on acquired investment securities 10.1 13.4 Other 4.8 2.4 Deferred tax assets $ 264.2 $ 323.2 December 31, 2023 2022 Deferred tax liabilities: Fixed assets, principally differences in bases and depreciation $ (19.8) $ (17.3) Deferred loan costs (4.1) (3.3) Investment in joint venture partnership, principally due to differences in depreciation of partnership assets (2.4) (1.3) Right of use assets (10.3) (11.3) Prepaid amounts (0.9) (0.9) Government agency stock dividends (1.3) (1.2) Goodwill and other intangibles (68.1) (68.2) Mortgage servicing rights (6.9) (7.4) Other (0.4) (1.8) Deferred tax liabilities (114.2) (112.7) Net deferred tax assets $ 150.0 $ 210.5 (1) As of December 31, 2023, the Company had remaining federal net operating loss carryforwards of $2.4 million from acquired companies, which is available to offset federal taxable income and state net operating loss carryforwards in amounts which vary by state. The federal net operating losses will expire beginning in 2030 and ending in 2036 and the state net operating losses will expire beginning in 2023 and ending in 2036. The use of these carryforwards is subject to annual limitations. The Company had current net income tax receivables of $16.4 million and $38.3 million at December 31, 2023 and 2022, respectively.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Company has equity awards outstanding under two stock-based compensation plans; The 2023 Equity and Incentive Plan (the “2023 Plan”) and the 2015 Equity Incentive Plan, as amended and restated (the “2015 Plan”). These plans were primarily established to enhance the Company’s ability to attract, retain, and motivate employees. The Company’s Board of Directors or, upon delegation, the Compensation and Human Capital Committee of the Board of Directors (“Compensation Human Capital Committee”) has exclusive authority to select employees, advisors and others, including directors, to receive awards and to establish the terms and conditions of each award made pursuant to the Company’s stock-based compensation plan. The 2023 Plan, approved by the Company’s shareholders in May 2023, was established to provide the Company with flexibility to select from various equity-based performance compensation methods, and to be able to address changing accounting and tax rules and corporate governance practices by optimally utilizing performance based compensation. The 2023 Plan did not increase the number of shares of the common stock available for awards under the 2015 Plan. At December 31, 2023, there were 1,389,724 common shares available for future grant under the 2023 Plan. The 2015 Plan, approved by the Company’s shareholders in May 2015, was established to provide the Company with flexibility to select from various equity-based performance compensation methods, and to be able to address changing accounting and tax rules and corporate governance practices by optimally utilizing performance based compensation. Upon approval of the 2023 Plan, the remaining common shares available for future grant under the 2015 were forfeited. The 2015 Plan continues with respect to the awards made prior to June 2023. Restricted Stock Awards. Common stock issued under the Company’s restricted stock plan may not be sold or otherwise transferred until restrictions have lapsed or performance objectives have been obtained. During the vesting periods, participants have voting rights and receive dividends on all time restricted shares and vesting performance restricted shares under the 2015 Plan. During the vesting periods, under the 2023 Plan, participants do not have voting rights and dividends are accumulated until the time upon which the award vests. Upon termination of employment, common shares upon which restrictions have not lapsed must be returned to the Company. All restricted share awards are classified as equity awards. The fair value of equity-classified restricted stock awards is based on the market price of the stock on the measurement date and is amortized as compensation expense on a straight-line basis over the period restrictions lapse or performance goals are met. Stock compensation is recognized based on the number of awards to vest using actual forfeiture amounts. For performance-based stock awards, an estimate is made of the number of shares expected to vest as a result of actual performance against the performance targets to determine the amount of compensation expense to be recognized. The estimate is reevaluated quarterly and total compensation expense is adjusted for any change in the current period. Stock-based compensation expense related to restricted stock awards of $4.7 million, $9.6 million and $8.9 million was included in employee benefits on the Company’s consolidated statements of income for the years ended December 31, 2023, 2022, and 2021, respectively. Related income tax expense of $0.4 million and $0.3 million for the years ended December 31, 2023 and 2022, respectively, and related income tax benefit of $0.3 million was recognized for the year ended December 31, 2021. The following table presents information regarding the Company’s restricted stock: As of December 31, 2023 Number of Weighted-Average Restricted stock, beginning of year 741,098 $ 38.94 Granted 683,574 19.84 Vested (180,587) 36.73 Forfeited (127,779) 29.75 Restricted stock, end of year 1,116,306 $ 27.74 During 2023, the Company issued 683,574 restricted common shares. The 2023 restricted share awards included 363,440 performance restricted shares, of which 181,720 vest in varying percentages upon achievement of defined return on average equity performance goals, and 181,720 vest in varying percentages upon achievement of defined total return to shareholder goals. The defined return to shareholder goals related to the 2020 performance restricted stock grants were not met resulting in the cancellation of 86,802 performance shares. Vesting of the 2023 performance restricted shares is also contingent on employment as of March 15, 2026. Additionally, 406,936 time-restricted shares were issued during 2023, of which 54,414 vest one year from the grant date, 97,665 vest two years from the grant date, and the remaining 254,857 vest one-third on each annual anniversary of the grant date, contingent on continued employment through the vesting dates. As of December 31, 2023, there was $22.2 million of unrecognized compensation cost related to non-vested, restricted stock awards expected to be recognized over a period of 1.35 years.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2023
Compensation Related Costs [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLAN Savings Plan. In addition, the Company has a contributory employee savings plan. All employees are eligible to participate in the plan. Employee participation in the plan is at the option of the employee. The Company contributed 100% of the first 6% of the participating employee’s eligible compensation in 2023, 2022, and 2021, respectively. Contribution expense for this plan of $12.7 million, $13.5 million, and $8.8 million in 2023, 2022, and 2021, respectively, is included in employee benefits expense in the Company’s consolidated statements of income.

Other Comprehensive Income

Other Comprehensive Income	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Other Comprehensive Income	OTHER COMPREHENSIVE INCOME (LOSS) The gross amounts of each component of other comprehensive (loss) income and the related tax effects for the periods indicated are as follows: Year Ended December 31, 2023 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized gain during period $ 144.8 $ 36.1 $ 108.7 Reclassification adjustment for net losses included in net income 23.5 5.8 17.7 Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale (7.2) (1.8) (5.4) Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity (1.3) (0.3) (1.0) Change in net unrealized gain on derivatives 0.9 0.3 0.6 Total other comprehensive income $ 160.7 $ 40.1 $ 120.6 Year Ended December 31, 2022 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (613.1) $ (152.4) $ (460.7) Reclassification adjustment for net losses included in net income 24.4 5.5 18.9 Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale 0.2 0.1 0.1 Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity (26.1) (6.6) (19.5) Change in net unrealized loss on derivatives (6.7) (1.8) (4.9) Total other comprehensive loss $ (621.3) $ (155.2) $ (466.1) Year Ended December 31, 2021 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (113.7) $ (28.7) $ (85.0) Reclassification adjustment for net gains included in net income (1.1) (0.3) (0.8) Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity 20.2 5.1 15.1 Change in net unrealized loss on derivatives 4.2 1.1 3.1 Total other comprehensive loss $ (90.4) $ (22.8) $ (67.6) The components of accumulated other comprehensive loss, net of income taxes, are as follows: Years ended December 31, 2023 2022 Net unrealized loss on investment securities available-for-sale $ (350.1) $ (471.0) Net unrealized (loss) gain on investment securities transferred to held-to-maturity (5.6) (4.5) Net unrealized (loss) gain on derivatives (0.8) (1.6) Net accumulated other comprehensive loss $ (356.5) $ (477.1)

Condensed Financial Information

Condensed Financial Information (Parent Company Only)	12 Months Ended
	Dec. 31, 2023
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information (Parent Company Only)	CONDENSED FINANCIAL INFORMATION (PARENT COMPANY ONLY) Following is condensed financial information of First Interstate BancSystem, Inc. December 31, 2023 2022 Condensed balance sheets: Cash and cash equivalents $ 275.7 $ 154.8 Investment in bank subsidiary 3,062.2 2,985.8 Advances to subsidiaries, net 43.5 0.1 Other assets 147.0 240.7 Total assets $ 3,528.4 $ 3,381.4 Other liabilities $ 38.8 $ 45.6 Long-term debt 99.0 98.9 Subordinated debentures held by subsidiary trusts 163.1 163.1 Total liabilities 300.9 307.6 Stockholders’ equity 3,227.5 3,073.8 Total liabilities and stockholders’ equity $ 3,528.4 $ 3,381.4 Years Ended December 31, 2023 2022 2021 Condensed statements of income: Dividends from subsidiaries $ 360.0 $ 360.0 $ 160.0 Other interest income 0.5 0.4 — Other income, primarily management fees from subsidiaries 51.6 51.7 41.3 Total income 412.1 412.1 201.3 Salaries and benefits 34.5 40.6 36.4 Interest expense 18.4 12.6 8.2 Acquisition related expenses — 62.3 11.6 Other operating expenses, net 22.5 25.0 17.6 Total expenses 75.4 140.5 73.8 Earnings before income tax benefit 336.7 271.6 127.5 Income tax benefit (4.2) (18.9) (7.6) Income before undistributed earnings of subsidiaries 340.9 290.5 135.1 Undistributed (loss) earnings of subsidiaries (83.4) (88.3) 57.0 Net income $ 257.5 $ 202.2 $ 192.1 Years Ended December 31, 2023 2022 2021 Condensed statements of cash flows: Cash flows from operating activities: Net income $ 257.5 $ 202.2 $ 192.1 Adjustments to reconcile net income to cash provided by operating activities: Undistributed losses (earnings) of subsidiaries 83.4 88.3 (57.0) Stock-based compensation expense 4.6 9.6 8.9 Other, net 2.7 (151.2) (3.2) Net cash provided by operating activities 348.2 148.9 140.8 Cash flows from investing activities: Acquisition of bank holding company, net of cash and cash equivalents received — (0.8) — Net cash used in investing activities $ — $ (0.8) $ — Years Ended December 31, 2023 2022 2021 Cash flows from financing activities: Net increase in advances from subsidiaries $ 1.8 $ 206.5 $ 23.7 Proceeds from issuance of common stock, net of stock issuance costs — 0.1 0.4 Purchase and retirement of common stock (34.0) (198.9) (5.4) Dividends paid to common stockholders (195.1) (182.1) (101.6) Net cash used in financing activities (227.3) (174.4) (82.9) Net change in cash and cash equivalents 120.9 (26.3) 57.9 Cash and cash equivalents, beginning of year 154.8 181.1 123.2 Cash and cash equivalents, end of year $ 275.7 $ 154.8 $ 181.1

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The three levels of inputs to measure fair value are as follows: • Level 1 - Quoted prices in active markets for identical assets or liabilities • Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of assets or liabilities The methodologies used by the Company in determining the fair values of each class of financial instruments are based primarily on independent, market-based data to reflect a value that would be reasonably expected in an orderly transaction between market participants at the measurement date, and therefore are classified within Level 2 of the valuation hierarchy. There have been no significant changes in the valuation techniques during the periods ended December 31, 2023 and 2022. The Company’s policy is to recognize transfers between levels as of the end of the reporting period. Transfers in and out of Level 1, Level 2, and Level 3 are recognized on the actual transfer date. There were no significant transfers between fair value hierarchy levels during the years ended December 31, 2023 and 2022. Further details on the methods used to estimate the fair value of each class of financial instruments above are discussed below: Investment Debt Securities Available-for-Sale . The Company obtains fair value measurements for investment securities from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information, and the investment’s terms and conditions, among others. Vendors chosen by the Company are widely recognized vendors whose evaluations support the pricing functions of financial institutions, investment and mutual funds, and portfolio managers. If needed, a broker may be utilized to determine the reported fair value of investment securities. Loans Held for Sale. Fair value measurements for residential mortgage loans held for sale are obtained from an independent pricing service. The fair value measurements consider observable data that may include binding contracts or quotes or bids from third party investors as well as loan level pricing adjustments. Commercial and agricultural loans held for sale are derived from quotes or bids from third party investors. Interest Rate Collars: The fair values of interest rate collars are obtained from an independent third party. The values are determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates fell below (rise above) the strike rate of the floors (caps). The variable interest rates used in the calculation of projected receipts on the collars are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The change in the value of derivative assets attributable to basis risk, or the risk that offsetting investments in a hedging strategy will not experience price changes in entirely opposite directions, was not significant in the reported periods. The Company also compares the reasonableness of the pricing semi-annually through a validation process involving additional independent third parties. Interest Rate Swap Contracts. Fair values for derivative interest rate swap contracts are obtained from an independent third party. The values are based upon the estimated amounts to settle the contracts considering current interest rates and are calculated using discounted cash flows that are observable, or that can be corroborated by observable market data. The inputs used to determine fair value include the United States Dollar – SOFR forward curve to estimate variable rate cash inflows and the SOFR to estimate the discount rate. The estimated variable rate cash inflows are compared to the fixed rate outflows and such difference is discounted to a present value to estimate the fair value of the interest rate swaps. The change in the value of derivative assets attributable to basis risk, or the risk that offsetting investments in a hedging strategy will not experience price changes in entirely opposite directions, was not significant in the reported periods. The Company also compares the reasonableness of the pricing semi-annually through a validation process involving additional independent third parties. For purposes of potential valuation adjustments to our derivative positions, we evaluate both our credit risk and the credit risk of our counterparties. Accordingly, we have considered factors such as the likelihood of our default and the default of our counterparties, our net exposures and remaining contractual life, among other things, in determining if any fair value adjustments related to credit risk are required. The change in value of derivative assets and derivative liabilities attributable to credit risk was not significant during the reported periods. Interest Rate Lock Commitments. Fair value measurements for interest rate lock commitments are obtained from an independent pricing service. The fair value measurements consider observable data that may include prices available from secondary market investors taking into consideration various characteristics of the loan, including the loan amount, interest rate, value of the servicing, and loan to value ratio, among other things. Observable data is then adjusted to reflect changes in interest rates, the Company’s estimated pull-through rate, and estimated direct costs necessary to complete the commitment into a closed loan net of origination and processing fees collected from the borrower. Forward Loan Sales Contracts. The fair value measurements for forward loan sales contracts are obtained from an independent pricing service. The fair value measurements consider observable data that includes sales of similar loans. Deferred Compensation Plan Assets and Liabilities. The fair values of deferred compensation plan assets and liabilities are based primarily on the use of independent, market-based data to reflect a value that would be reasonably expected in an orderly transaction between market participants at the measurement date. These investments are in the same funds and purchased in the same amounts as the participants’ selected investments, which represent the underlying liabilities to plan participants. Deferred compensation plan liabilities are recorded at amounts due to participants, based on the fair value of participants’ selected investments. Financial assets and financial liabilities measured at fair value on a recurring basis are as follows: Fair Value Measurements at Reporting Date Using As of December 31, 2023 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 224.7 $ — $ 224.7 $ — State, county, and municipal securities 219.8 — 219.8 — Obligations of U.S. government agencies 168.5 — 168.5 — U.S. agency commercial mortgage-backed securities 1,105.6 — 1,105.6 — U.S. agency residential mortgage-backed securities 1,366.9 — 1,366.9 — Collateralized mortgage obligations 1,189.5 — 1,189.5 — Private mortgage-backed securities 210.4 — 210.4 — Collateralized loan obligations 1,119.7 — 1,119.7 — Corporate securities 236.4 — 236.4 — Loans held for sale 0.5 — 0.5 — Derivative assets: Interest rate swap contracts 37.3 — 37.3 — Interest rate lock commitments 0.1 — 0.1 — Derivative liabilities: Interest rate collars 3.6 — 3.6 — Interest rate swap contracts 123.5 — 123.5 — Risk participation agreements 0.1 — 0.1 — Forward loan sales contracts 0.1 — 0.1 — Deferred compensation plan assets 19.2 — 19.2 — Deferred compensation plan liabilities 19.2 — 19.2 — Fair Value Measurements at Reporting Date Using As of December 31, 2022 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 642.7 $ — $ 642.7 $ — State, county, and municipal securities 263.7 — 263.7 — Obligations of U.S. government agencies 198.9 — 198.9 — U.S. agency commercial mortgage-backed securities 1,351.2 — 1,351.2 — U.S. agency residential mortgage-backed securities 1,558.3 — 1,558.3 — Collateralized mortgage obligations 1,350.2 — 1,350.2 — Private mortgage-backed securities 228.0 — 228.0 — Collateralized loan obligations 1,111.6 — 1,111.6 — Corporate securities 241.5 — 241.5 — Loans held for sale 12.4 — 6.9 5.5 Derivative assets: Interest rate swap contracts 45.1 — 45.1 — Forward loan sales contracts 0.1 — 0.1 — Derivative liabilities: Interest rate collars 5.4 — 5.4 — Interest rate swap contracts 154.2 — 154.2 — Deferred compensation plan assets 18.7 — 18.7 — Deferred compensation plan liabilities 18.7 — 18.7 — Additionally, from time to time, certain assets are measured at fair value on a non-recurring basis. Adjustments to fair value generally result from the application of lower-of-cost-or-market accounting or write-downs of individual assets due to credit deterioration. The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis: Fair Value Measurements at Reporting Date Using As of December 31, 2023 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Collateral-dependent loans $ 52.6 $ — $ — $ 52.6 Loans held for sale 46.9 — — 46.9 Other real estate owned 16.5 — — 16.5 Long-lived assets to be disposed of by sale 1.0 — — 1.0 Fair Value Measurements at Reporting Date Using As of December 31, 2022 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Collateral-dependent loans $ 39.1 $ — $ — $ 39.1 Loans held for sale 67.5 — — 67.5 Other real estate owned 12.7 — — 12.7 Long-lived assets to be disposed of by sale 5.5 — — 5.5 Collateral-dependent Loans. Collateral-dependent loans are reported at the fair value of the underlying collateral if repayment is expected solely from collateral. The collateral-dependent loans are reported at fair value through specific valuation allowance allocations. In addition, when it is determined that the fair value of a collateral-dependent loan is less than the recorded investment in the loan, the carrying value of the loan is adjusted to fair value through a charge to the allowance for credit losses. Collateral values are estimated using independent appraisals and management estimates of current market conditions. As of December 31, 2023 and December 31, 2022, the Company had collateral-dependent loans with a carrying and fair value of $52.6 million and $39.1 million, respectively. Loans Held for Sale. Fair value measurements for non-residential mortgage loans held for sale are derived from valuations, appraisals, and quotes or bids from third party investors. The fair value measurements consider observable data that may include binding contracts or quotes or bids from third party investors as well as loan level pricing adjustments. OREO. The fair values of OREO are estimated using independent appraisals and management estimates of current market conditions. Upon initial recognition, write-downs based on the foreclosed asset’s fair value at foreclosure are reported through charges to the allowance for credit losses. Periodically, the fair value of foreclosed assets is remeasured with any subsequent write-downs charged to OREO expense in the period in which they are identified. Long-lived Assets to be Disposed of by Sale. Long-lived assets to be disposed of by sale are carried at the lower of carrying value or fair value less estimated costs to sell. The fair values of long-lived assets to be disposed of by sale are based upon observable market data and management estimates of current market conditions. As of December 31, 2023, the Company had long-lived assets to be disposed of by sale with carrying and fair values aggregating $1.0 million. As of December 31, 2022, the Company had long-lived assets to be disposed of by sale with carrying values aggregating $5.7 million, reduced by write-downs of $0.2 million charged to other expense, and fair values aggregating $5.5 million The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values: As of December 31, 2023 Fair Value Valuation Technique Unobservable Inputs Range (Weighted Average) Collateral-dependent loans $ 52.6 Appraisal Appraisal adjustment —% - 100% (36%) Loans held for sale 46.9 Fair value of collateral Discount for type of property, age of appraisal, and current status 5% - 23% (14)% Other real estate owned 16.5 Appraisal Appraisal adjustment 10% - 43% (48)% Long-lived assets to be disposed of by sale 1.0 Appraisal Appraisal adjustment —% - —% —% As of December 31, 2022 Collateral-dependent loans $ 39.1 Appraisal Appraisal adjustment 0% - 45% (7%) Loans held for sale 67.5 Fair value of collateral Discount for type of property, age of appraisal, and current status 11% 23% (17%) Other real estate owned 12.7 Appraisal Appraisal adjustment 15% - 36% (22%) Long-lived assets to be disposed of by sale 5.5 Appraisal Appraisal adjustment 0% - 6% (3%) The Company is required to disclose the fair value of financial instruments for which it is practical to estimate fair value. The methodologies for estimating the fair value of financial instruments that are measured at fair value on a recurring or non-recurring basis are discussed above. The methodologies for estimating the fair value of other financial instruments are discussed below. For financial instruments bearing a variable interest rate where no credit risk exists, it is presumed that recorded book values are reasonable estimates of fair value. Financial Assets. Carrying values of cash, cash equivalents, and accrued interest receivable approximate fair values due to the liquid and/or short-term nature of these instruments. Fair values for investment securities held-to-maturity are obtained from an independent pricing service, which considers observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information, and the investment’s terms and conditions, among other things. Fair values of fixed rate loans and variable rate loans that reprice on an infrequent basis are estimated by discounting future cash flows using current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality using an exit price notion. Carrying values of variable rate loans that reprice frequently, and with no change in credit risk, approximate the fair values of these instruments. Financial Liabilities. The fair values of demand deposits, savings accounts, securities sold under repurchase agreements, and accrued interest payable are the amounts that are payable on demand at the reporting date. The fair values of fixed-maturity certificates of deposit are estimated using external market rates that are currently offered for deposits that have similar remaining maturities. The fair values of derivative liabilities are obtained from an independent pricing service, which considers observable data that may include the United States Dollar - SOFR forward curve, the federal funds effective swap rate and cash flows, among other things. The fixed and floating rate subordinated debentures, floating rate subordinated term loan, other borrowed funds, fixed rate subordinated term debt, and capital lease obligation are estimated by discounting future cash flows using current rates for advances that have similar characteristics. Commitments to Extend Credit and Standby Letters of Credit. The fair value of commitments to extend credit and standby letters of credit, based on fees currently charged to enter into similar agreements, is not significant. The estimated fair values of financial instruments that are reported in the Company’s consolidated balance sheets, and are segregated by the level of the valuation inputs within the fair value hierarchy that are utilized to measure fair value, are as follows: ` Fair Value Measurements at Reporting Date Using As of December 31, 2023 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Financial assets: Cash and cash equivalents $ 578.0 $ 578.0 $ 578.0 $ — $ — Investment debt securities available-for-sale 5,841.5 5,841.5 — 5,841.5 — Investment debt securities held-to-maturity 3,207.9 2,874.0 — 2,874.0 — Accrued interest receivable 129.1 129.1 — 129.1 — Mortgage servicing rights, net 28.3 38.8 — 38.8 — Loans held for sale 47.4 47.4 — 0.5 46.9 Net loans held for investment 18,051.9 17,334.4 — 17,281.8 52.6 Derivative assets 37.4 37.4 — 37.4 — Deferred compensation plan assets 19.2 19.2 — 19.2 — Total financial assets $ 27,940.7 $ 26,899.8 $ 578.0 $ 26,222.3 $ 99.5 Financial liabilities: Total deposits, excluding time deposits $ 20,313.2 $ 20,313.2 $ 20,313.2 $ — $ — Time deposits 3,009.9 2,981.7 — 2,981.7 — Securities sold under repurchase agreements 782.7 782.7 — 782.7 — Other borrowed funds 2,603.0 2,603.0 — 2,603.0 — Accrued interest payable 52.2 52.2 — 52.2 — Long-term debt 120.8 115.6 — 115.6 — Subordinated debentures held by subsidiary trusts 163.1 151.1 — 151.1 — Derivative liabilities 127.3 127.3 — 127.3 — Deferred compensation plan liabilities 19.2 19.2 — 19.2 — Total financial liabilities $ 27,191.4 $ 27,146.0 $ 20,313.2 $ 6,832.8 $ — Fair Value Measurements at Reporting Date Using As of December 31, 2022 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 870.5 $ 870.5 $ 870.5 $ — $ — Investment debt securities available-for-sale 6,946.1 6,946.1 — 6,946.1 — Investment debt securities held-to-maturity 3,451.8 3,052.2 — 3,052.2 — Accrued interest receivable 118.3 118.3 — 118.3 — Mortgage servicing rights, net 31.1 37.4 — 37.4 — Loans held for sale 79.9 79.9 — 6.9 73.0 Net loans held for investment 17,879.1 17,552.1 — 17,513.0 39.1 Derivative assets 45.2 45.2 — 45.2 — Deferred compensation plan assets 18.7 18.7 — 18.7 — Total financial assets $ 29,440.7 $ 28,720.4 $ 870.5 $ 27,737.8 $ 112.1 Financial liabilities: Total deposits, excluding time deposits $ 23,145.2 $ 23,145.2 $ 23,145.2 $ — $ — Time deposits 1,928.4 1,876.1 — 1,876.1 — Securities sold under repurchase agreements 1,052.9 1,052.9 — 1,052.9 — Other borrowed funds 2,327.0 2,327.0 — 2,327.0 — Accrued interest payable 14.5 14.5 — 14.5 — Long-term debt 120.8 116.3 — 116.3 — Subordinated debentures held by subsidiary trusts 163.1 155.8 — 155.8 — Derivative liabilities 159.6 159.6 — 159.6 — Deferred compensation plan liabilities 18.7 18.7 — 18.7 — Total financial liabilities $ 28,930.2 $ 28,866.1 $ 23,145.2 $ 5,720.9 $ —

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS Certain executive officers, directors, and greater than 5% shareholders of the Company and certain entities and individuals related to such persons had transactions with the Company in the ordinary course of business. These parties were deposit clients of the Bank and incurred indebtedness in the form of loans, as clients, of $11.1 million and $18.9 million at December 31, 2023 and 2022, respectively. During 2023, new loans and advances on existing loans of $5.8 million were funded, loan repayments totaled $6.1 million, and $7.5 million of loans were removed or added due to changes in related parties. All deposit and loan transactions were made on substantially the same terms, including interest rates and collateral, as those prevailing at the time for comparable transactions with persons not related to the Company and do not involve more than a normal risk of collectability or present other unfavorable features.

Authoritative Accounting Guidan

Authoritative Accounting Guidance	12 Months Ended
	Dec. 31, 2023
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recent Authoritative Accounting Guidance	RECENT AUTHORITATIVE ACCOUNTING GUIDANCE ASU 2020-04, “Reference Rate Reform (Topic 848), Facilitation of the Effects of Reference Rate Reform on Financial Accounting.” In March 2020, the FASB issued ASU 2020-04, which provides temporary exceptions that are optional for applying GAAP to loan and lease agreements, derivative contracts, and other transactions affected by the anticipated transition away from LIBOR toward new interest rate benchmarks. For transactions that are modified because of reference rate reform and that meet certain scope guidance (i) modifications of loan agreements should be accounted for by prospectively adjusting the effective interest rate, with such modification considered to be "minor" so that any existing unamortized origination fees/costs will carry forward and continue to be amortized and (ii) modifications of lease agreements should be accounted for as a continuation of the existing agreement with no reassessments of the lease classification and the discount rate or remeasurements of lease payments that otherwise would be required for modifications will not be accounted for as separate contracts. ASU 2020-04 is effective March 12, 2020 through December 31, 2022. An entity may elect to apply ASU 2020-04 for contract modifications as of January 1, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. Once elected for a Topic or an Industry Subtopic within the Codification, the amendments in this ASU must be applied prospectively for all eligible contract modifications for that Topic or Industry Subtopic. The Company adopted certain elections related to cash flow hedges which did not have a significant impact on the Company’s financial position or results of operations. Based upon the amendments provided in ASU 2022-06 discussed below, ASU 2020-04 can generally be applied through December 31, 2024. ASU 2021-01, “ Reference Rate Reform (Topic 848) ” In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform Topic 848 , that clarifies certain exceptions that are optional in Topic 848 for contract modifications and hedge accounting and apply those exceptions to derivatives that are affected by the discounting transition. An entity may elect to apply the amendments in this ASU on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or on a prospective basis to new modifications from any date within an interim period that includes or is subsequent to the date of the issuance of a final ASU. If an entity elects to apply any of the amendments in this ASU for an eligible hedging relationship, any adjustments as a result of those elections must be reflected as of the date the entity applies the election. The amendments in this ASU do not apply to contract modifications made, new hedging relationships entered into, or existing hedging relationships evaluated for effectiveness in periods after December 31, 2022, except for hedging relationships existing as of December 31, 2022, that apply certain exceptions that are optional in which the accounting effects of the hedging activity are recorded through the end of the hedging relationship. The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position or results of operations. Based upon the amendments provided in ASU 2022-06 discussed below, ASU 2021-01 can generally be applied through December 31, 2024. ASU 2021-08, “ Business Combinations (Topic 805), Accounting for Contract Assets and Contract Liabilities from Contracts with Customers ” In October 2021, the FASB issued ASU 2021-08, Business Combinations Topic 805, Accounting for Contract Assets and Contract Liabilities from Contracts with Customers , to address diversity in practice and inconsistency related to the accounting for revenue contracts with customers acquired in a business combination. The amendments require that an entity recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with Topic 606 as if it had originated the contracts. The amendments also provide certain practical expedients for acquirers when recognizing and measuring acquired contract assets and contract liabilities from revenue contracts in a business combination and applies to contract assets and contract liabilities from other contracts to which the provisions of Topic 606 apply. The amendments are effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. Entities should apply the amendments prospectively to business combinations that occur after the effective date. The amendments in this ASU became effective for the Company on January 1, 2023 and did not have a significant impact on the Company’s consolidated financial statements, results of operations, or liquidity. ASU 2022-01, “ Derivatives and Hedging (Topic 815), Fair Value Hedging—Portfolio Layer Method ” In March 2022, the FASB issued ASU 2022-01, Derivatives and Hedging Topic 815, Fair Value Hedging—Portfolio Layer Method that clarifies the accounting for and promotes consistency in the reporting of hedge basis adjustments applicable to both a single hedged layer and multiple hedged layers. The amendments allow nonprepayable financial assets also to be included in a closed portfolio hedged using the portfolio layer method. That expanded scope permits an entity to apply the same portfolio hedging method to both prepayable and nonprepayable financial assets, thereby allowing consistent accounting for similar hedges. The amendments are effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. The amendments in this ASU became effective for the Company on January 1, 2023 and did not have a significant impact on the Company’s consolidated financial statements, results of operations, or liquidity. ASU 2022-02, “ Financial Instruments—Credit Losses (Topic 326), Troubled Debt Restructurings and Vintage Disclosures ” In March 2022, the FASB issued ASU 2022-02, Financial Instruments—Credit Losses (Topic 326), Troubled Debt Restructurings (TDRs) and Vintage Disclosures that eliminate the accounting guidance for TDRs by creditors in Subtopic 310-40, Receivables—Troubled Debt Restructurings by Creditors, while enhancing disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. Rather than applying the recognition and measurement guidance for TDRs, an entity must apply the loan refinancing and restructuring guidance to determine whether a modification results in a new loan or a continuation of an existing loan. The amendment also requires an entity disclose current-period gross writeoffs by year of origination for financing receivables and net investments in leases within the scope of Subtopic 326. The amendments are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. The amendments in this ASU became effective for the Company on January 1, 2023 on a prospective basis, and did not have a significant impact on the Company’s consolidated financial statements, results of operations, or liquidity. Prior to the adoption of ASU 2022-02, a TDR occurred when a loan to a borrower experiencing financial difficulty was restructured with a concession provided that a creditor would not otherwise consider. For the Company’s accounting policy related to TDRs granted prior to the adoption of ASU 2022-02, see “Note 1 – Summary of Significant Accounting Policies” in Part IV, Item 15 “Notes to Consolidated Financial Statements” within our Annual Report on Form 10-K for the year ended December 31, 2022. See “Note 6 – Loans Held For Investment” of these Notes to the Unaudited Consolidated Financial Statements” for further details of the amendments in this update. ASU 2022-06, “ Reference Rate Reform (Topic 848), Deferral of the Sunset Date of Topic 848 ” In December 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848), Deferral of the Sunset Date of Topic 848 that extends the period of time preparers can utilize the reference rate reform relief guidance provided by ASU 2020-04 and ASU 2021-01, which are discussed above. ASU 2022-06, which was effective upon issuance, defers the sunset date of this prior guidance from December 31, 2022 to December 31, 2024, after which entities will no longer be permitted to apply the relief guidance in Topic 848. The adoption of ASU 2022-06 did not have a significant impact on the Company’s financial position, results of operations, or liquidity. ASU 2023-02, “ Investments—Equity Method and Joint Ventures (Topic 323), Accounting for Investments in Tax Credit Structures Using the Proportional Amortization Method ” In March 2023, the FASB issued ASU 2023-02, Investments—Equity Method and Joint Ventures (Topic 323), Accounting for Investments in Tax Credit Structures Using the Proportional Amortization Method that permit reporting entities to elect to account for their tax equity investments, regardless of the tax credit program from which the income tax credits are received, using the proportional amortization method if certain conditions are met. Previously, this method was only available for qualifying tax equity investments in low-income housing tax credit structures. The amendments also require that a reporting entity disclose certain information in annual and interim reporting periods that enable investors to understand certain information about its investments that generate income tax credits and other income tax benefits from a tax credit program. For public business entities, the amendments are effective for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. Early adoption is permitted for all entities in any interim period. If an entity adopts the amendments in an interim period, it shall adopt them as of the beginning of the fiscal year that includes that interim period. The amendments must be applied on either a modified retrospective or a retrospective basis (except for certain LIHTC investments not accounted for using the proportional amortization method). The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position, results of operations, or liquidity. ASU 2023-05, “ Business Combinations—Joint Venture Formations (Subtopic 805-60), Recognition and Initial Measurement ” In August 2023, the FASB issued ASU 2023-05, Business Combinations—Joint Venture Formations (Subtopic 805-60), Recognition and Initial Measurement that requires certain joint ventures to apply a new basis of accounting upon formation by recognizing and initially measuring most of their assets and liabilities at fair value. The objectives of the amendments are to provide decision-useful information to investors and other allocators of capital in a joint venture's financial statements and also to reduce diversity in practice. These amendments are effective prospectively for all joint venture formations with a formation date on or after January 1, 2025. The Company does not anticipate the adoption of ASU 2023-05 will have a significant impact on the Company’s financial position, results of operations, or liquidity. ASU 2023-06, “ Disclosure Improvements—Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative ” In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements—Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative that amends the ASC to incorporate certain disclosure requirements from SEC Release No. 33-10532 - Disclosure Update and Simplification that was issued in 2018. The effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. The Company does not anticipate the adoption of ASU 2023-06 will have a significant impact on the Company’s financial position, results of operations, or liquidity. ASU 2023-09, “ Income Taxes (Topic 740): Improvements to Income Tax Disclosures ” In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures that require public business entities to annually disclose (1) specific categories in their rate reconciliation; (2) additional information for reconciling items that meet a quantitative threshold; (3) the amount of income taxes paid (net of refunds received) disaggregated by federal, state, and foreign taxes; (4) the amount of income taxes paid (net of refunds received) disaggregated by individual jurisdictions in which the income taxes paid that meet a quantitative threshold; (5) income (or loss) from continuing operations before income tax expense (or benefit) disaggregated between domestic and foreign; and (6) income tax expense (or benefit) from continuing operations disaggregated by federal, state, and foreign. The ASU eliminates the requirement to disclose the nature and estimate of the range of the reasonably possible change in the unrecognized tax benefits balance in the next 12 months and to disclose the cumulative amount of each type of temporary difference when a deferred tax liability is not recognized because of the exceptions to comprehensive recognition of deferred taxes related to subsidiaries and corporate joint ventures. For public business entities, the amendments are effective for annual periods beginning after December 15, 2024. Early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance. The amendments should be applied on a prospective basis, but retrospective application is permitted. The Company is currently evaluating the impact of the standard and does not anticipate it will have a significant impact on the Company’s financial position, results of operations, or liquidity.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Subsequent events have been evaluated for potential recognition and disclosure through the date financial statements were filed with the Securities and Exchange Commission. On January 26, 2024, the Company declared a quarterly dividend to common shareholders of $0.47 per share, which was paid on February 19, 2024 to shareholders of record as of February 9, 2024. In the first quarter of 2024, the Company accessed $1.0 billion of borrowings at a rate of 4.76% through the BTFP with a maturity of January 16, 2025, which enabled the Company to pay off higher rate FHLB advances and support its current cash position. No other events requiring recognition or disclosure were identified.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Revenue	Revenue Recognition. The Company recognizes revenue as it is earned based on contractual terms, as transactions occur, or as services are provided and collectability is reasonably assured. The principal source of revenue is interest income from loans and investments. The Company also earns non-interest income from various banking and financial services offered to its clients. Certain specific policies related to non-interest income include the following: Wealth management and trust fee income Wealth management and trust fee income represents monthly or other periodic fees due from wealth management clients as consideration for managing the clients’ assets. Wealth management and trust services include custody of assets, investment management, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed. The Company does not earn performance-based incentives. Optional services such as estate settlement and other court appointed services are available to existing trust and asset management clients. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time. Service charges on deposit accounts Service charges on deposit accounts represent general service fees for account maintenance and activity- or transaction-based fees and consist of transaction-based revenue, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when our performance obligation is completed for account maintenance services or when a transaction has been completed (such as a wire transfer or check orders). Payment for such performance obligations are generally received at a point in time when the performance obligations are satisfied. Interchange and other fees Interchange and other fees primarily represent debit and credit card income comprised of interchange fees earned whenever the Company’s debit and credit cards are processed through card payment networks such as MasterCard. ATM fees are primarily generated when a Company cardholder uses a non-Company ATM or a non-Company cardholder uses a Company ATM. Merchant services income primarily represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. Swap fee income primarily represents income associated with the execution of dealer bank swap agreements. Other service charges include revenue from processing wire transfers, bill pay service, cashier’s checks, and other services. The Company’s performance obligation for interchange and other service charges are largely satisfied, and related revenue recognized, when completion of the services are rendered at a point in time. Annuity and insurance commissions Annuity and insurance commissions primarily represent commissions received on annuity and insurance product sales. The Company acts as an intermediary between the Company’s client and the insurance carrier. The Company’s performance obligation is generally satisfied upon the issuance of the annuity or insurance policy, the carrier then remits the commission payment to the Company, and the Company recognizes the revenue at a point in time.
Consolidation Policy	Basis of Presentation . The Company’s consolidated financial statements include the accounts of the Parent Company and its operating subsidiaries. As of December 31, 2023, the Company had one significant subsidiary, First Interstate Bank (“FIB”). All significant intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications, none of which were material, have been made in the consolidated financial statements for 2022 and 2021 to conform to the 2023 presentation. These reclassifications did not change previously reported net income or stockholders’ equity.
Equity Method Investments	Equity Method Investments. The Company has investments in real estate joint ventures that are not consolidated because the Company does not own a majority voting interest, control the operations, or receive a majority of the losses or earnings of the joint venture. These joint ventures are accounted for using the equity method of accounting whereby the Company initially records its investment at cost (or fair value at the date of acquisition) and then subsequently adjusts the carrying value for the Company’s proportionate share of distributions and earnings or losses of the joint ventures.
Variable Interest Entities	Variable Interest Entities. The Company’s wholly owned business trusts, FI Statutory Trust I (“Trust I”), FI Capital Trust II (“Trust II”), FI Statutory Trust III (“Trust III”), FI Capital Trust IV (“Trust IV”), FI Statutory Trust V (“Trust V”), FI Statutory Trust VI (“Trust VI”), Northwest Bancorporation Capital Trust I (“Trust VII”), GWB Capital Trust VI (“Trust VIII”), Sunstate Bancshares Trust II (Trust IX”), Great Western Statutory Trust IV (“Trust X”), HF Financial Capital Trust III (“Trust XI”), HF Trust IV (“Trust XII”), HF Trust V (“Trust XIII”), and HF Trust VI (“Trust XIV”) are variable interest entities for which the Company is not a primary beneficiary. Accordingly, the accounts of Trust I through Trust XIV are not included in the accompanying consolidated financial statements, and are instead accounted for using the equity method of accounting.
Assets Held In Fiduciary Or Agency Capacity	Assets Held in Fiduciary or Agency Capacity.
Use of Estimates	Use of Estimates. The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and income and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to change relate to the determination of the allowance for credit losses, the valuation of goodwill and intangible assets, and fair values of investment securities and other financial instruments.
Cash and Cash Equivalents	Cash and Cash Equivalents
Goodwill and Core Deposit Intangibles	Goodwill . The excess purchase price over the fair value of net assets from acquisitions, or goodwill, is evaluated for impairment at least annually and on an interim basis if an event or circumstance indicates that it is likely impairment has occurred. Goodwill impairment is determined by comparing the fair value of a reporting unit to its carrying amount. In any given year the Company may elect to perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is in excess of its carrying value. If it is not more likely than not that the fair value of the reporting unit is in excess of the carrying value, or if the Company elects to bypass the qualitative assessment, a quantitative impairment test is performed. In performing a quantitative test for impairment, the fair value of net assets is estimated based on analyses of the Company’s market value, discounted cash flows and peer values. The determination of goodwill impairment is sensitive to market-based economics and other key assumptions used in determining or allocating fair value. Variability in the market and changes in assumptions or subjective measurements used to allocate fair value are reasonably possible and may have a material impact on our consolidated financial statements or results of operations. Core Deposit and Other Customer Relationship Intangibles. Intangible assets consist of core deposit intangibles and other customer relationship intangibles. Core deposit intangibles represent the intangible value of depositor relationships resulting from deposit liabilities assumed, as a result of acquisitions, and are amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is generally ten years. Other customer relationship intangibles represent the value of the identifiable intangible value assigned to customer relationships arising from acquired companies and are amortized using the straight-line method over the estimated useful life, which is 12 years.
Mortgage Servicing Rights	Mortgage Servicing Rights . The Company recognizes the rights to service mortgage loans for others, whether acquired or internally originated. Mortgage servicing rights are initially recorded at fair value based on comparable market data and are amortized in proportion to and over the period of estimated net servicing income. Mortgage servicing rights are evaluated quarterly for impairment by discounting the expected future cash flows, taking into consideration the estimated level of prepayments based on current industry expectations and the predominant risk characteristics of the underlying loans including loan type, note rate, and loan term. Impairment adjustments, if any, are recorded through a valuation allowance.
Premises and Equipment	Premises and Equipment . Buildings, furniture, and equipment are stated at cost less accumulated depreciation. Depreciation expense is computed using straight-line methods over estimated useful lives of 5 to 45 years for buildings and improvements and 3 to 15 years for furniture and equipment. Leasehold improvements and assets acquired under a financing lease are amortized over the shorter of their estimated useful lives or the terms of the related leases. Land is recorded at cost. Costs incurred for maintenance and repairs are expensed as incurred.
Company-Owned Life Insurance	Company-Owned Life Insurance . Key executive and group life insurance policies are recorded at their cash surrender value. Separate account group life insurance policies are subject to a stable value contract that offsets the impact of interest rate fluctuations on the market value of the policies and are recorded at the stabilized investment value. Increases in the cash surrender or stabilized investment value of insurance policies, as well as insurance proceeds received, are recorded as other non-interest income, and are not subject to income taxes.
Deferred Compensation Plan	Deferred Compensation Plan.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets.
Other Real Estate Owned	Other Real Estate Owned (OREO)
Restricted Equity Securities	Restricted Equity Securities.
Derivatives and Hedging Activities	Derivatives and Hedging Activities. For asset and liability management purposes, the Company enters into interest rate swap contracts to hedge against changes in forecasted cash flows due to interest rate exposures. Interest rate swaps are contracts in which a series of interest payments are exchanged over a prescribed period. The notional amount upon which the interest payments are based is not exchanged. The Company formally assesses, both at the hedge's inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows of hedged items. The gain or loss on cash flow hedging instruments is initially reported as a component of other comprehensive income and subsequently reclassified into earnings in the same period during which the transaction affects earnings. When it is determined that a derivative is not highly effective as a hedge or that it has ceased to be a highly effective hedge, the Company discontinues hedge accounting prospectively when (a) it is determined that the derivative is no longer effective in offsetting changes in the cash flows of a hedged item (including forecasted transactions); (b) the derivative expires or is sold, terminated, or exercised; (c) the derivative is de-designated as a hedge instrument, because it is unlikely that a forecasted transaction will occur; or (d) management determines that designation of the derivative as a hedge instrument is no longer appropriate. When hedge accounting is discontinued because it is probable that a forecasted transaction will not occur, the derivative will continue to be carried on the balance sheet at its fair value, and gains and losses that were accumulated in other comprehensive income will be recognized immediately in earnings. In all other situations in which hedge accounting is discontinued, the derivative will be carried at its fair value on the balance sheet, with subsequent changes in its fair value recognized in current-period earnings. The Company also enters into certain interest rate swap contracts that are not designated as hedging instruments. These derivative contracts relate to transactions in which the Company enters into an interest rate swap with a client while at the same time entering into an offsetting interest rate swap with a third-party financial institution. Because the Company acts as an intermediary for the client, changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact the Company’s results of operations. In the normal course of business, the Company enters into interest rate lock commitments to finance residential mortgage loans that are not designated as accounting hedges. These commitments, which contain fixed expiration dates, offer the borrower an interest rate guarantee provided the loan meets underwriting guidelines and closes within the timeframe established by the Company. Interest rate risk arises on these commitments and subsequently closed loans if interest rates change between the time of the interest rate lock and the delivery of the loan to the investor. Loan commitments related to residential mortgage loans intended to be sold are considered derivatives and are marked to market through earnings. In addition to the effects of the change in market interest rate, the fair value measurement of the derivative also contemplates the expected cash flows to be received from the counterparty from the future sale of the loan. The Company sells residential mortgage loans on either a best efforts or mandatory delivery basis. The Company mitigates the effect of the interest rate risk inherent in providing interest rate lock commitments by entering into forward loan sales contracts. During the interest rate lock commitment period, these forward loan sales contracts are marked to market through earnings and are not designated as accounting hedges. Exclusive of the fair value component associated with the projected cash flows from the loan delivery to the investor, the changes in fair value related to movements in market rates of the interest rate lock commitments and the forward loan sales contracts generally move in opposite directions, and the net impact of changes in these valuations on net income during the loan commitment period is generally inconsequential. When the loan is funded to the borrower, the interest rate lock commitment derivative expires and the Company records a loan held for sale. The forward loan sales contract acts as a hedge against the variability in cash to be received from the loan sale. The changes in measurement of the estimated fair values of the interest rate lock commitments and forward loan sales contracts are included in mortgage banking revenues in the accompanying consolidated statements of income.
Earnings Per Common Share	Earnings Per Common Share . Basic and diluted earnings per common share are calculated using a two-class method. Under the two-class method, basic earnings per common share is calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding during the period, excluding outstanding participating securities. Participating securities include non-vested performance restricted stock awards granted and all non-vested time restricted stock awards. Diluted earnings per common share is calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding determined for the basic earnings per share calculation plus the dilutive effect of stock compensation using the treasury stock method.
Income Taxes	Income Taxes . The Parent Company and its subsidiaries have elected to be included in a consolidated federal income tax return. For state income tax purposes, the combined taxable income of the Parent Company and its subsidiaries is apportioned among the states in which operations take place. Federal and state income taxes attributable to the subsidiaries, computed on a separate return basis, are paid to or received from the Parent Company. The Company accounts for income taxes using the liability method. Under the liability method, deferred tax assets and liabilities are determined based on enacted income tax rates which will be in effect when the differences between the financial statement carrying values and tax bases of existing assets and liabilities are expected to be reported in taxable income.
Comprehensive Income	Comprehensive Income (Loss). Comprehensive income (loss) includes net income, as well as other changes in stockholders’ equity that result from transactions and economic events other than those with shareholders. In addition to net income, the Company’s comprehensive income (loss) includes the after tax effect of changes in unrealized gains and losses on available-for-sale investment securities and derivatives designated as fair value or cash flow hedges, and changes in the unamortized gain or loss on available-for-sale investment securities transferred to held-to-maturity.
Segment Reporting	Segment Reporting.
Advertising Costs	Advertising Costs.
Transfers of Financial Assets	Transfers of Financial Assets. Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when the assets have been isolated from the Company; the transferee obtains the right, free of conditions that constrain it from taking advantage of that right, to pledge or exchange the transferred assets; and, the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Stock-Based Compensation	Stock-Based Compensation
Fair Value Measurements	Fair Value Measurements. In general, fair value measurements are based upon quoted market prices, where available. If quoted market prices are not available, fair value measurements are estimated using relevant market information and other assumptions. Fair value estimates involve uncertainties and require some degree of judgment regarding interest rates, credit risk, prepayments and other factors. The use of different assumptions or estimation techniques may have a significant effect on the fair value amounts reported.
Business Combinations Policy	Business Combinations.
Internal Use Software, Policy	Software.
Investment Securities	Debt Security Investments. Investments in debt securities that the Company has the positive intent and ability to hold to maturity are classified as held-to-maturity and carried at amortized cost. Investments in debt securities that may be sold in response to or in anticipation of changes in interest rates and resulting prepayment risk, or other factors, are classified as available-for-sale and carried at fair value. The unrealized gains and losses on these securities are reported, net of applicable income taxes, as a separate component of stockholders’ equity and comprehensive income. Management determines the appropriate classification of securities at the time of purchase and at each reporting date management reassesses the appropriateness of the classification.
Credit Loss, Financial Instrument	Allowance for Credit Losses - Held-to-Maturity Securities: Management measures expected credit losses on held-to-maturity debt securities on a collective basis by major security type. Accrued interest receivable on held-to-maturity debt securities is excluded from the estimate of credit losses. The estimate of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Management classifies the held-to-maturity portfolio into the following major security types: U.S. Treasury notes. U.S. Treasury notes issued by the U.S. Department of the Treasury are guaranteed by the U.S. government with very little risk to default. State, county, and municipal securities. Municipal bonds issued by municipal governments within the U.S. These types of securities are primarily composed of general obligation bonds, or municipal bonds backed by the credit and taxing power of the issuing jurisdiction and revenue obligation bonds, or municipal bonds that are financed by income-producing projects and are secured by a specified source of revenue. Municipal issues shall have at least a “BBB” rating by Moody's and/or Standard and Poor’s, or equivalent creditworthiness must be established prior to purchase. All non-rated or private placement securities must be analyzed and approved by the Company’s Credit Department and documented prior to purchase. Obligations of U.S. government agencies and entities. Securities held by the Company are primarily issued by The Federal Home Loan Mortgage Corporation, known as Freddie Mac, and The Federal National Mortgage Association, known as Fannie Mae, which are implicitly guaranteed by the U.S. government and are consistently highly rated by major rating agencies with very little risk to default. U.S. agency commercial mortgage-backed securities. Commercial mortgage-backed securities held by the Company are primarily issued by U.S. government agencies and entities. These securities are either explicitly or implicitly guaranteed by the U.S. government, are consistently highly rated by major rating agencies with very little risk to default. U.S. agency residential mortgage-backed securities. Residential mortgage-backed securities held by the Company are primarily issued by U.S. government agencies and entities. These securities are either explicitly or implicitly guaranteed by the U.S. government, are consistently highly rated by major rating agencies with very little risk to default. Collateralized mortgage obligations. Collateralized mortgage obligations include agency and non-agency residential securities which carry ratings no lower than investment grade “BBB” and pass the federal financial institutions examinations test (Collateral Mortgage Obligation volatility test) at the time of purchase. Corporate securities. Securities held by the Company are primarily comprised of corporate bonds (both senior and subordinated-debt) issued by a firm or public entity which carry ratings no lower than investment grade “BBB” or better by Moody’, Standard and Poor’s, or Kroll rating agencies. All corporate subordinated-debt securities are analyzed and approved by the Company prior to purchase. Allowance for Credit Losses - Available-For-Sale Securities: For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security's amortized cost basis is written down to fair value through income. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company performs a qualitative assessment as to whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income.
Finance, Loan and Lease Receivables, Held-for-investment, Allowance and Nonperforming Loans, Nonperforming Loans Policy	Mortgage loans that are 180 days past due and commercial loans are charged off to the extent principal or interest is deemed uncollectible. Consumer and credit card loans continue to accrue interest until they are charged off no later than 120 days past due unless the loan is in the process of collection. Past-due status is based on the contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful.
Loans and Leases Receivable, Lease Financing, Policy	Loans Held for Investment. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost or principal balance outstanding. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts and deferred loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized in interest income using the level-yield method without anticipating prepayments. Accrued interest receivable on loans held for investment totaled $86.1 million and $76.5 million at December 31, 2023 and 2022, respectively, and was reported in the accrued interest receivable line item on the consolidated balance sheets. Interest income is accrued on the unpaid principal balance of underlying loans. Interest income on mortgage and commercial loans is discontinued and placed on nonaccrual status at the time the loan is 90 days delinquent unless the loan is well secured and in process of collection.
Deteriorated Loans Transferred in	Purchased Credit Deteriorated (“PCD”) Loans
Off-Balance-Sheet Credit Exposure, Policy
Financing Receivable, Held-for-sale	Loans Held for Sale. The Company originates certain loans intended for sale in the secondary market. Conforming agency mortgage production is sold on a servicing retained basis. Certain loans, such as government guaranteed mortgage loans, are sold on a servicing released basis. Residential loans the Company originated with the intent to sell are classified as loans held for sale and recorded at fair value, determined individually, as of the balance sheet date. The loan’s fair value includes the servicing value of the loans as well as any accrued interest. The fair value of loans held for sale are primarily determined based on quoted prices for similar loans in active markets or outstanding commitments from third-party investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to non-interest income in the consolidated statements of operations. Net gains and losses on loan sales are recorded as a component of non-interest income. Performing residential real estate loans that are held for sale are generally sold with servicing rights retained. Upon the sale of an originated loan, the mortgage servicing right is recorded at its estimated fair value.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed	The following table provides the purchase price allocation as of the acquisition date and the Great Western assets acquired and liabilities assumed at their estimated fair value as of the acquisition date. We recorded the estimate of fair value based on valuations at the acquisition date. The excess value of the consideration paid over the fair value of assets acquired and liabilities assumed was recorded as goodwill. The purchase price allocation resulted in goodwill of $479.3 million, of which $31.7 million is deductible for income tax purposes. Goodwill resulting from the acquisition was allocated to the Company’s one operating segment, community banking, and consists largely of the synergies and economies of scale expected from combining the operations of Great Western and the Company. All amounts reported were finalized during the fourth quarter of 2022. As of February 1, 2022 Assets acquired: Cash and cash equivalents $ 2,006.9 Investment securities 2,699.0 Securities purchased under agreement to resell 101.1 Loans held for sale 217.0 Loans held for investment 7,705.0 Allowance for credit losses (59.5) Premises and equipment, including right of use lease assets 144.7 Other real estate owned 15.8 Company owned life insurance 186.6 Core deposit intangibles 50.1 Customer relationship intangible 22.8 Mortgage servicing rights 1.3 Deferred tax assets, net 60.2 Other assets 200.8 Total assets acquired 13,351.8 Liabilities assumed: Deposits 11,688.0 Securities sold under repurchase agreements 74.0 Accrued expenses and other liabilities 110.4 FHLB advances 122.9 Subordinated debt 36.4 Subordinated debentures held by subsidiary trusts 76.1 Total liabilities assumed 12,107.8 Net assets acquired $ 1,244.0 Consideration paid: Class A common stock 1,723.3 Total consideration paid (1) $ 1,723.3 Goodwill $ 479.3 (1) Includes $13 thousand of cash paid in lieu of fractional shares.
Financing Receivable, Purchased	The non-credit discount or premium, after the adjustment for the allowance for credit losses, is accreted to interest income using the interest method based on the effective interest rate determined after the adjustment for credit losses at the adoption date. Information regarding loans acquired at the acquisition date as amended for measurement period adjustments as of December 31, 2022 were as follows: (In millions) PCD loans: Unpaid principal balance $ 979.2 Principal amounts previously written off by GWB (238.7) Interest applied to principal by GWB (18.1) Adjusted unpaid principal balance 722.4 Credit discount (69.2) Discount attributable to other factors (29.9) Fair value 623.3 Allowance for credit losses 59.5 Amortized cost basis 682.8 Non-PCD loans: Unpaid principal balance 7,107.9 Credit discount (1) (76.5) Non-credit discount (9.2) Fair value 7,022.2 Amortized cost basis $ 7,705.0 (1) Represents the best estimate of the contractual cash flows not expected to be collected as of the acquisition date.
Business Acquisition, Pro Forma Information	The following table presents certain pro forma financial information for the years ended December 31, 2022 and 2021 as if GWB had been acquired on January 1, 2021. This pro forma information combines the historical results of GWB with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition occurred at the beginning of the year prior to the acquisition. The pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value, cost savings, or business synergies. As a result, actual amounts would have differed from the pro forma information presented, and the differences could be significant. December 31, 2022 2021 Total revenues $ 1,223.3 $ 1,200.9 Net income $ 351.6 $ 243.3 Earnings per common share (Basic) $ 3.28 $ 2.24 Earnings per common share (Diluted) $ 3.28 $ 2.24

Goodwill and Core Deposit Int_2

Goodwill and Core Deposit Intangibles (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Change in Carrying Amount of Goodwill	The following table details changes in the recorded amount of goodwill as of the dates indicated: Year Ended December 31, 2023 2022 Net carrying value at beginning of period $ 1,100.9 $ 621.6 Additions to goodwill from acquisition — 479.3 Net carrying value at end of period $ 1,100.9 $ 1,100.9 The Company performed its annual impairment assessment as of July 1, 2023 and 2022 concluding there was no impairment to goodwill. As a result of the ongoing financial services economic conditions, including changes to the interest rate environment, continued volatility in the Company’s common share price, and volatility in the Company’s overall market capitalization during the third and beginning of the fourth quarter of 2023, we performed a quantitative impairment assessment as of October 31, 2023 and concluded the fair value of our single reporting unit exceeded its respective carrying value and did not result in impairment for the reporting unit. The quantitative assessment of goodwill for the reporting unit was performed utilizing a discounted cash flow analysis (“income approach”) and estimates of selected market information (“market approaches”). The income approach measures the fair value of an interest in a business by discounting expected future cash flows to present value. The market approaches take into consideration fair values of comparable companies operating in similar lines of business that are potentially subject to similar economic and environmental factors and could be considered reasonable investment alternatives. The result of the income and market approaches were weighted in determining the fair value of the reporting unit.
Schedule of Activity of Identifiable Core Deposit Intangibles	Other intangible assets are comprised of core deposit intangibles (“CDI”) and other customer relationship intangibles (“OCRI”) and amounted to the following at December 31, 2023 and 2022: December 31, 2023 CDI OCRI Total Gross other intangible assets, at January 1, 2023 $ 154.7 $ 22.8 $ 177.5 Accumulated amortization (92.5) (3.6) (96.1) Net other intangible assets, end of period $ 62.2 $ 19.2 $ 81.4 December 31, 2022 Gross other intangible assets, at January 1, 2022 $ 106.0 $ — $ 106.0 Amounts established through acquisition 50.1 22.8 72.9 Reductions due to sale of health savings accounts (1.4) — (1.4) Accumulated amortization (78.8) (1.7) (80.5) Net other intangible assets, end of period $ 75.9 $ 21.1 $ 97.0
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table provides the estimated aggregate future amortization expense of other intangible assets: Years ending December 31, CDI OCRI Total 2024 $ 12.7 $ 1.9 $ 14.6 2025 11.8 1.9 13.7 2026 10.9 1.9 12.8 2027 8.2 1.9 10.1 2028 5.7 1.9 7.6 Thereafter 12.9 9.7 22.6 Total $ 62.2 $ 19.2 $ 81.4

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Amortized Cost and Approximate Fair Values of Investment Securities	The amortized cost and the approximate fair values of investment securities are summarized as follows: December 31, 2023 Amortized Allowance for Credit Losses Net Amortized Cost Gross Gross Estimated Available-for-Sale: U.S. Treasury notes $ 250.2 $ — $ 250.2 $ — $ (25.5) $ 224.7 State, county, and municipal securities 256.7 — 256.7 — (36.9) 219.8 Obligations of U.S. government agencies 179.4 — 179.4 — (10.9) 168.5 U.S. agency commercial mortgage-backed securities 1,192.7 — 1,192.7 0.6 (87.7) 1,105.6 U.S. agency residential mortgage-backed securities 1,496.3 — 1,496.3 1.2 (130.6) 1,366.9 Collateralized mortgage obligations 1,308.5 — 1,308.5 1.3 (120.3) 1,189.5 Private mortgage-backed securities 241.3 — 241.3 — (30.9) 210.4 Collateralized loan obligations 1,121.9 — 1,121.9 0.1 (2.3) 1,119.7 Corporate securities 260.8 — 260.8 — (24.4) 236.4 Total $ 6,307.8 $ — $ 6,307.8 $ 3.2 $ (469.5) $ 5,841.5 December 31, 2023 Amortized Cost 1 Allowance for Credit Losses Net Amortized Cost Gross Unrealized Gains Gross Estimated Held-to Maturity: U.S. Treasury notes $ 399.0 $ — $ 399.0 $ — $ (2.8) $ 396.2 State, county, and municipal securities 179.2 — 179.2 0.2 (24.2) 155.2 Obligations of U.S. government agencies 354.5 — 354.5 — (42.4) 312.1 U.S. agency commercial mortgage-backed securities 510.5 — 510.5 — (52.9) 457.6 U.S. agency residential mortgage-backed securities 1,232.6 — 1,232.6 — (137.0) 1,095.6 Collateralized mortgage obligations 475.9 — 475.9 0.2 (69.0) 407.1 Corporate securities 57.0 (0.8) 56.2 — (6.0) 50.2 Total $ 3,208.7 $ (0.8) $ 3,207.9 $ 0.4 $ (334.3) $ 2,874.0 (1) Amortized cost presented above includes $10.7 million of unamortized gains in U.S. agency residential and commercial mortgage-backed securities and collateralized mortgage obligations related to the 2021 transfer of securities from available-for-sale to held-to-maturity, and $18.1 million of unamortized losses in state, county, and municipal, obligations of U.S. government agencies and corporate securities related to the 2022 transfer of securities from available-for-sale to held-to-maturity. December 31, 2022 Amortized Allowance for Credit Losses Net Amortized Cost Gross Gross Estimated Available-for-Sale U.S. Treasury notes $ 675.1 $ — $ 675.1 $ 2.1 $ (34.5) $ 642.7 State, county, and municipal securities 314.3 — 314.3 — (50.6) 263.7 Obligations of U.S. government agencies 216.2 — 216.2 — (17.3) 198.9 U.S. agency commercial mortgage-backed securities 1,468.0 — 1,468.0 0.2 (117.0) 1,351.2 U.S. agency residential mortgage-backed securities 1,726.0 — 1,726.0 — (167.7) 1,558.3 Collateralized mortgage obligations 1,491.5 — 1,491.5 — (141.3) 1,350.2 Private mortgage-backed securities 264.9 — 264.9 — (36.9) 228.0 Collateralized loan obligations 1,145.2 — 1,145.2 — (33.6) 1,111.6 Corporate securities 272.3 — 272.3 — (30.8) 241.5 Total $ 7,573.5 $ — $ 7,573.5 $ 2.3 $ (629.7) $ 6,946.1 December 31, 2022 Amortized Cost 1 Allowance for Credit Losses Net Amortized Cost Gross Gross Estimated Held-to Maturity U.S. Treasury notes $ 396.6 $ — $ 396.6 $ — $ (10.2) $ 386.4 State, county, and municipal securities 181.2 (0.1) 181.1 0.2 (31.6) 149.7 Obligations of U.S. government agencies 351.7 — 351.7 — (49.6) 302.1 U.S. agency commercial mortgage-backed securities 526.8 — 526.8 — (58.3) 468.5 U.S. agency residential mortgage-backed securities 1,391.5 — 1,391.5 — (166.6) 1,224.9 Collateralized mortgage obligations 525.8 — 525.8 0.2 (76.7) 449.3 Corporate securities 80.1 (1.8) 78.3 — (7.0) 71.3 Total $ 3,453.7 $ (1.9) $ 3,451.8 $ 0.4 $ (400.0) $ 3,052.2 (1) Amortized cost presented above includes $20.2 million of unamortized losses and of $14.2 million unamortized gains related to the 2021 and 2022 transfer of securities from available-for-sale to held-to-maturity.
Gross Unrealized Losses and Fair Values of Investment Securities	The following tables show the gross unrealized losses and fair values of available-for-sale investment securities and the length of time individual investment securities have been in an unrealized loss position as of December 31, 2023 and 2022. Less than 12 Months 12 Months or More Total December 31, 2023 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ — $ — $ 224.7 $ (25.5) $ 224.7 $ (25.5) State, county, and municipal securities — — 217.1 (36.9) 217.1 (36.9) Obligations of U.S. government agencies — — 168.0 (10.9) 168.0 (10.9) U.S. agency commercial mortgage-backed securities 0.2 — 1,083.1 (87.7) 1,083.3 (87.7) U.S. agency residential mortgage-backed securities 0.7 — 1,287.5 (130.6) 1,288.2 (130.6) Collateralized mortgage obligations — — 1,142.4 (120.3) 1,142.4 (120.3) Private mortgage-backed securities — — 210.5 (30.9) 210.5 (30.9) Collateralized loan obligations — — 935.7 (2.3) 935.7 (2.3) Corporate securities — — 236.5 (24.4) 236.5 (24.4) Total $ 0.9 $ — $ 5,505.5 $ (469.5) $ 5,506.4 $ (469.5) Less than 12 Months 12 Months or More Total December 31, 2022 Fair Gross Fair Gross Fair Gross Available-for-Sale U.S. Treasury notes $ 168.8 $ (4.7) $ 170.4 $ (29.8) $ 339.2 $ (34.5) State, county, and municipal securities 104.9 (9.0) 146.1 (41.6) 251.0 (50.6) Obligations of U.S. government agencies 152.2 (10.1) 46.1 (7.2) 198.3 (17.3) U.S. agency commercial mortgage-backed securities 1,069.8 (59.9) 270.8 (57.0) 1,340.6 (116.9) U.S. agency residential mortgage-backed securities 1,213.5 (112.3) 344.6 (55.4) 1,558.1 (167.7) Collateralized mortgage obligations 1,016.4 (90.1) 333.0 (51.3) 1,349.4 (141.4) Private mortgage-backed securities 133.1 (19.1) 94.9 (17.8) 228.0 (36.9) Collateralized loan obligations 1,082.6 (33.1) 28.9 (0.5) 1,111.5 (33.6) Corporate securities 130.6 (8.3) 110.8 (22.5) 241.4 (30.8) Total $ 5,071.9 $ (346.6) $ 1,545.6 $ (283.1) $ 6,617.5 $ (629.7)
Debt Securities, Held-to-maturity, Allowance for Credit Loss	The following table presents the activity in the allowance for credit losses related to held-to-maturity investment securities: Year Ended December 31, 2023 2022 2021 Beginning balance $ 1.9 $ — $ — (Reduction of) provision for credit losses (1.1) 1.9 — Ending balance $ 0.8 $ 1.9 $ —
Debt Securities, Held-to-maturity, Credit Quality Indicator	The following table summarizes the credit quality indicators of held-to-maturity securities at amortized cost for the periods indicated: December 31, 2023 AAA AA A BBB BB Not Rated Total U.S. Treasury notes $ 399.0 $ — $ — $ — $ — $ — $ 399.0 State, county, and municipal securities 69.0 92.3 10.6 — — 7.3 179.2 Obligations of U.S. government agencies 354.5 — — — — — 354.5 U.S. agency commercial mortgage-backed securities FNMA/FHLMC 359.7 — — — — — 359.7 GNMA 150.8 — — — — — 150.8 U.S. agency residential mortgage-backed securities FNMA/FHLMC 1,189.8 — — — — — 1,189.8 GNMA 42.8 — — — — — 42.8 Collateralized mortgage obligations FNMA/FHLMC 334.1 — — — — — 334.1 GNMA 141.8 — — — — — 141.8 Corporate securities — — — 47.0 5.0 5.0 57.0 Total $ 3,041.5 $ 92.3 $ 10.6 $ 47.0 $ 5.0 $ 12.3 $ 3,208.7 December 31, 2022 AAA AA A BBB BB Not Rated Total U.S. Treasury notes $ 396.6 $ — $ — $ — $ — $ — $ 396.6 State, county, and municipal securities 68.3 92.8 11.5 — — 8.6 181.2 Obligations of U.S. government agencies 351.7 — — — — — 351.7 U.S. agency commercial mortgage-backed securities FNMA/FHLMC 364.9 — — — — — 364.9 GNMA 161.9 — — — — — 161.9 U.S. agency residential mortgage-backed securities FNMA/FHLMC 1,342.9 — — — — — 1,342.9 GNMA 48.6 — — — — — 48.6 Collateralized mortgage obligations FNMA/FHLMC 525.8 — — — — — 525.8 Corporate securities — — — 65.1 10.0 5.0 80.1 Total $ 3,260.7 $ 92.8 $ 11.5 $ 65.1 $ 10.0 $ 13.6 $ 3,453.7
Maturities of Investment Securities	Available-for-Sale Held-to-Maturity December 31, 2023 Amortized Estimated Amortized Estimated Within one year $ 40.1 $ 39.4 $ 309.1 $ 307.5 After one year but within five years 1,004.4 938.7 346.6 329.4 After five years but within ten years 1,373.9 1,255.4 654.0 579.1 After ten years 3,889.4 3,608.0 1,899.0 1,658.0 Total $ 6,307.8 $ 5,841.5 $ 3,208.7 $ 2,874.0

Loans Held for Sale (Tables)

Loans Held for Sale (Tables)	12 Months Ended
	Dec. 31, 2023
Loans Held for Sale [Abstract]
Loans Held for Sale (Table)	The following table presents loans held for sale by class of receivable for the dates indicated: December 31, December 31, Loans held for sale: Agricultural 1 $ 19.6 $ 62.5 Commercial real estate, at lower of cost or market 27.3 — Construction real estate, at lower of cost or market — 10.5 Residential mortgage, at fair value 0.5 6.9 Total loans held for sale $ 47.4 $ 79.9 1 As of December 31, 2023 the agricultural loans held were at lower of cost or market. At December 31, 2022, the Company held $57.0 million of agricultural loans at lower of cost or market and $5.5 million of agricultural loans on accrual status at fair value with an unpaid principal balance of $7.7 million, of which $5.6 million is 90 days or more past due. The table below presents the non-residential mortgage loans held for sale activity for the 2023 period: Agricultural Construction Real Estate Commercial Real Estate Beginning balance $ 62.5 $ 10.5 $ — Loans held for investment transferred to loans held for sale — 3.1 27.3 Loans held for sale transferred to loans held for investment (29.6) — — Loans held for sale transferred to OREO — (6.4) — Repayments and discounted pay-offs (15.5) — — Loan disposals — (3.1) — Increase (decrease) in estimated fair value of the loans 1 2.2 (4.1) — Ending balance $ 19.6 $ — $ 27.3 1 For the year ended December 31, 2023, the Company recorded a gain of $2.2 million and a loss of $4.1 million in other income within the consolidated statements of income related to fair value changes.

Loans Held for Investment (Tabl

Loans Held for Investment (Tables)	12 Months Ended
	Dec. 31, 2023
Receivables [Abstract]
Schedule of Loans by Class	The following table presents loans by class of receivable and portfolio segment as of the dates indicated: 2023 2022 Real estate: Commercial $ 8,869.2 $ 8,528.6 Construction 1,826.5 1,944.4 Residential 2,244.3 2,188.3 Agricultural 716.8 794.9 Total real estate 13,656.8 13,456.2 Consumer: Indirect 740.9 829.7 Direct and advance lines 141.6 152.9 Credit card 76.5 75.9 Total consumer 959.0 1,058.5 Commercial 2,906.8 2,882.6 Agricultural 769.4 708.3 Other, including overdrafts 0.1 9.2 Loans held for investment 18,292.1 18,114.8 Deferred loan fees and costs (12.5) (15.6) Loans held for investment, net of deferred fees and costs 18,279.6 18,099.2 Allowance for credit losses (227.7) (220.1) Net loans held for investment $ 18,051.9 $ 17,879.1
Schedule of Allowance for Loan Losses by Portfolio Segment	The following tables represent, by loan portfolio segments, the activity in the allowance for credit losses for loans held for investment: December 31, 2023 Beginning Balance Provision for (reversal of) Loans Charged-Off (2) Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate $ 138.7 $ 35.2 $ (18.5) $ 4.7 $ 160.1 Consumer 23.3 (1.0) (14.0) 4.7 13.0 Commercial 54.9 (3.9) (3.4) 2.6 50.2 Agricultural 3.2 0.8 — 0.4 4.4 Total allowance for credit losses $ 220.1 $ 31.1 $ (35.9) $ 12.4 $ 227.7 December 31, 2022 Beginning Balance ACL Recorded for PCD Loans Provision for (reversal of) Credit Loss Loans Charged-Off (2) Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 17.3 $ 17.2 $ (4.2) $ (3.5) $ 0.4 $ 27.2 Owner occupied 13.3 9.5 (2.7) (2.5) 1.9 19.5 Multi-family 13.3 10.9 8.7 (5.7) 0.7 27.9 Total commercial real estate 43.9 37.6 1.8 (11.7) 3.0 74.6 Construction: Land acquisition & development 0.5 3.4 (0.4) (2.6) 0.4 1.3 Residential construction 2.4 — 1.1 — 0.1 3.6 Commercial construction 6.0 0.2 31.6 (6.6) — 31.2 Total construction 8.9 3.6 32.3 (9.2) 0.5 36.1 Residential real estate: Residential 1-4 family 13.4 0.1 6.9 (0.2) 0.3 20.5 Home equity and HELOC 1.2 — — (0.1) 0.5 1.6 Total residential real estate 14.6 0.1 6.9 (0.3) 0.8 22.1 Agricultural real estate 1.9 2.3 1.5 (0.2) 0.4 5.9 Total real estate 69.3 43.6 42.5 (21.4) 4.7 138.7 Consumer: Indirect 14.3 — 2.7 (4.0) 2.3 15.3 Direct and advance lines 4.6 — 2.2 (3.7) 2.1 5.2 Credit card 2.2 — 2.4 (2.4) 0.6 2.8 Total consumer 21.1 — 7.3 (10.1) 5.0 23.3 Commercial: Commercial and floor plans 27.1 11.2 15.1 (6.6) 2.2 49.0 Commercial purpose secured by 1-4 family 4.4 0.2 1.2 (0.2) 0.1 5.7 Credit card 0.1 — 1.4 (1.3) — 0.2 Total commercial 31.6 11.4 17.7 (8.1) 2.3 54.9 Agricultural: Agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total agricultural 0.3 4.5 0.9 (5.4) 2.9 3.2 Total allowance for credit losses $ 122.3 $ 59.5 $ 68.4 $ (45.0) $ 14.9 $ 220.1 December 31, 2021 Beginning Balance Provision for (reversal of) Credit Loss Loans Charged-Off (2) Recoveries Collected Ending Balance Allowance for credit losses (1) Real estate: Commercial real estate: Non-owner occupied $ 25.5 $ (8.3) $ — $ 0.1 $ 17.3 Owner occupied 18.3 (2.7) (2.3) — 13.3 Multi-family 11.0 2.3 — — 13.3 Total commercial real estate 54.8 (8.7) (2.3) 0.1 43.9 Construction: Land acquisition & development 1.3 (0.1) (1.2) 0.5 0.5 Residential construction 1.6 0.9 (0.1) — 2.4 Commercial construction 7.3 (1.3) (0.1) 0.1 6.0 Total construction 10.2 (0.5) (1.4) 0.6 8.9 Residential real estate: Residential 1-4 family 11.4 2.0 — — 13.4 Home equity and HELOC 1.4 (0.4) (0.1) 0.3 1.2 Total residential real estate 12.8 1.6 (0.1) 0.3 14.6 Agricultural real estate 2.7 (0.1) (0.7) — 1.9 Total real estate 80.5 (7.7) (4.5) 1.0 69.3 Consumer: Indirect 16.7 (1.4) (3.5) 2.5 14.3 Direct and advance lines 4.6 1.7 (2.9) 1.2 4.6 Credit card 2.6 0.6 (1.8) 0.8 2.2 Total consumer 23.9 0.9 (8.2) 4.5 21.1 Commercial: Commercial and floor plans 34.2 (7.3) (3.0) 3.2 27.1 Commercial purpose secured by 1-4 family 4.7 (0.5) (0.3) 0.5 4.4 Credit card 0.3 0.1 (0.4) 0.1 0.1 Total commercial 39.2 (7.7) (3.7) 3.8 31.6 Agricultural: Agricultural 0.7 (0.2) (0.2) — 0.3 Total agricultural 0.7 (0.2) (0.2) — 0.3 Total allowance for credit losses $ 144.3 $ (14.7) $ (16.6) $ 9.3 $ 122.3 (1) Amounts presented exclude the allowance for credit losses related to unfunded commitments and investment securities. The allowance for credit losses related to unfunded commitments and investment securities are included in the “Financial Instruments with Off-Balance Sheet Risk” Note and “Investment Securities” Note, respectively. (2) Loans, or portions thereof, are charged-off against the allowance for credit losses when management believes the collectability of the principal is unlikely, or, with respect to consumer installment loans, according to an established delinquency schedule.
Schedule of Recorded Investment in Impaired Loans	The following tables present the principal balance of collateral-dependent loans by class of receivable as of the dates indicated: Collateral Type As of December 31, 2023 Business Assets Real Property Other Total Real estate: Commercial $ — $ 26.6 $ — $ 26.6 Construction — 17.0 — 17.0 Residential — 0.5 — 0.5 Agricultural — 1.2 — 1.2 Total real estate — 45.3 — 45.3 Commercial 4.5 1.4 0.7 6.6 Agricultural 0.7 — — 0.7 Total collateral-dependent loans $ 5.2 $ 46.7 $ 0.7 $ 52.6 Collateral Type As of December 31, 2022 Business Assets Real Property Other Total Real estate: Commercial $ 1.7 $ 15.8 $ — $ 17.5 Construction — 3.2 — 3.2 Residential — 0.5 — 0.5 Agricultural 0.2 5.8 — 6.0 Total real estate 1.9 25.3 — 27.2 Commercial 3.1 1.5 — 4.6 Agricultural 2.1 5.2 — 7.3 Total collateral-dependent loans $ 7.1 $ 32.0 $ — $ 39.1
Schedule of Recorded Investment in Past Due Loans by Class	Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans classified in the following table as 90 days or more past due continue to accrue interest. The following tables present the contractual aging of the Company’s recorded principal balance of loans by class of receivable as of the dates indicated: Total Loans 30 - 59 60 - 89 90 or more 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2023 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 12.7 $ 6.1 $ — $ 18.8 $ 8,822.2 $ 28.2 $ 8,869.2 Construction 3.1 0.4 — 3.5 1,805.8 17.2 1,826.5 Residential 11.9 3.1 0.6 15.6 2,218.0 10.7 2,244.3 Agricultural 1.8 — — 1.8 709.6 5.4 716.8 Total real estate 29.5 9.6 0.6 39.7 13,555.6 61.5 13,656.8 Consumer: Indirect 8.0 2.2 0.4 10.6 727.6 2.7 740.9 Direct 0.9 0.2 — 1.1 140.2 0.3 141.6 Credit card 0.7 0.5 0.6 1.8 74.7 — 76.5 Total consumer 9.6 2.9 1.0 13.5 942.5 3.0 959.0 Commercial 14.5 1.1 0.3 15.9 2,879.4 11.5 2,906.8 Agricultural 0.1 — 3.0 3.1 735.9 30.4 769.4 Other, including overdrafts — — — — 0.1 — 0.1 Loans held for investment $ 53.7 $ 13.6 $ 4.9 $ 72.2 $ 18,113.5 $ 106.4 $ 18,292.1 Total Loans 30 - 59 60 - 89 90 or more 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2022 Past Due Past Due Past Due Past Due Loans Loans (1) Loans Real estate Commercial $ 5.6 $ 0.8 $ 1.1 $ 7.5 $ 8,501.5 $ 19.6 $ 8,528.6 Construction 10.4 0.6 0.6 11.6 1,929.1 3.7 1,944.4 Residential 9.9 2.1 1.2 13.2 2,168.7 6.4 2,188.3 Agricultural 1.1 6.1 — 7.2 780.1 7.6 794.9 Total real estate 27.0 9.6 2.9 39.5 13,379.4 37.3 13,456.2 Consumer: Indirect 9.3 2.4 0.6 12.3 814.7 2.7 829.7 Direct 0.8 0.3 0.1 1.2 151.4 0.3 152.9 Credit card 0.8 0.4 0.6 1.8 74.1 — 75.9 Total consumer 10.9 3.1 1.3 15.3 1,040.2 3.0 1,058.5 Commercial 7.1 1.7 2.1 10.9 2,861.5 10.2 2,882.6 Agricultural 0.8 2.2 0.1 3.1 696.5 8.7 708.3 Other, including overdrafts — — — — 9.2 — 9.2 Loans held for investment $ 45.8 $ 16.6 $ 6.4 $ 68.8 $ 17,986.8 $ 59.2 $ 18,114.8 (1) As of December 31, 2023 and 2022, none of our non-accrual loans were earning interest income. Additionally, no material interest income was recognized on non-accrual loans at December 31, 2023 and 2022, respectively. There were $2.7 million and $1.5 million in reversals of accrued interest at December 31, 2023 and 2022, respectively.
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The following table reconciles the par value, or initial amortized cost, of PCD loans acquired in the GWB acquisition as of February 1, 2022, or the date of the acquisition with the purchase price (or initial fair value of the loans) as amended for measurement period adjustments: Purchase price (initial fair value) $ 623.3 Allowance for credit losses (1) 298.2 Discount attributable to other factors (2) 57.7 Par value (unpaid principal balance) $ 979.2 (1) For acquired PCD loans, an allowance of $298.2 million was required with a corresponding increase to the amortized cost basis as of the acquisition date. For PCD loans where all or a portion of the loan balance had been previously written-off by GWB, or would be subject to write-off under the Company’s charge-off policy, a CECL allowance of $238.7 million, included as part of the grossed-up loan balance at acquisition was immediately written-off. The net impact to the allowance for PCD assets on the acquisition date was $59.5 million. (2) Non-credit discount includes the difference between the amortized cost basis and the unpaid principal balance of $39.6 million established on PCD loans acquired from GWB and interest applied to principal of $18.1 million.
Financing receivable, Modified	The following table presents the amortized cost basis of loans at December 31, 2023 that were both experiencing financial difficulty and modified during the year ended December 31, 2023, by class and by type of modification. The percentage of the principal balance of loans that were modified to borrowers in financial difficulty as compared to the principal balance of each class of receivable is also presented below: December 31, 2023 Principal Forgiveness Term Extension Rate Reduction Term Extension and Interest Rate Reduction Total % of Total Class of Loans Held for Investment (1) Real estate: Commercial $ 1.5 $ 28.6 $ 1.1 $ 0.6 $ 31.8 0.36 % Construction — 13.7 — — 13.7 0.75 Residential 0.1 0.6 — — 0.7 0.03 Agricultural — 6.4 — — 6.4 0.89 Total real estate 1.6 49.3 1.1 0.6 52.6 0.39 Consumer: Indirect — 0.1 — — 0.1 0.01 Direct and advance lines — 0.1 — — 0.1 0.07 Total consumer — 0.2 — — 0.2 0.02 Commercial — 7.4 — 0.2 7.6 0.26 Agricultural — 36.1 — — 36.1 4.69 Loans held for investment (2) $ 1.6 $ 93.0 $ 1.1 $ 0.8 $ 96.5 0.53 % (1) Based on the principal balance as of period end, divided by the period end principal balance of the corresponding class of receivables. (2) As of December 31, 2023, the Company excluded $1.6 million in accrued interest from the amortized cost of the identified loans. The Company monitors the performance of loan modifications to borrowers experiencing financial difficulty to understand the effectiveness of its modification efforts. Of the loans that were modified during the year ended December 31, 2023, there were $6.7 million of loans classified as past due 30 days or more, with the remaining loans performing in accordance with the modified terms and are classified as current at December 31, 2023. There were no commitments to lend additional funds to borrowers experiencing financial difficulty whose terms have been modified during the year ended December 31, 2023 through either principal forgiveness, interest rate reduction, term extension, or other than insignificant payment delay. The following table presents the financial effect of the loan modifications presented above to borrowers experiencing financial difficulty during the year ended December 31, 2023: Term Extension and Interest Rate Reduction Principal Forgiveness Weighted-Average Months of Term Extension Weighted-Average Interest Rate Reduction Weighted-Average Months of Term Extension Weighted-Average Interest Rate Reduction Real estate: Commercial $ 1.3 5.8 0.35 % 6.0 0.25 % Construction — 9.1 — 0.0 — Residential 0.3 131.6 — 0.0 — Agricultural — 4.5 — 0.0 — Total real estate 1.6 Consumer: Indirect — 8.3 — 0.0 — Direct and advance lines — 62.1 — 0.0 — Total consumer — Commercial — 12.2 — 14.6 0.51 Agricultural — 9.2 — 0.0 — Loans held for investment (1) $ 1.6 (1) Balances based on loan original contractual terms.

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Premises and Equipment and Related Accumulated Depreciation	Premises and equipment and related accumulated depreciation are as follows: December 31, 2023 2022 Land $ 87.7 $ 86.7 Buildings and improvements 474.2 469.2 Furniture and equipment 111.6 111.0 Total premises and equipment 673.5 666.9 Less accumulated depreciation (229.2) (222.2) Premises and equipment, net $ 444.3 $ 444.7

Company-Owned Life Insurance (T

Company-Owned Life Insurance (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, All Other Investments [Abstract]
Schedule of Life Insurance Corporate or Bank Owned	Company-owned life insurance consists of the following: December 31, 2023 2022 Key executive, principal shareholder $ 1.8 $ 3.2 Key executive split dollar 5.0 7.1 Group life 495.6 487.6 Total $ 502.4 $ 497.9

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	12 Months Ended
	Dec. 31, 2023
Repossessed Assets [Abstract]
Other Real Estate Owned	Information with respect to the Company’s other real estate owned follows: Year Ended December 31, 2023 2022 2021 Balance at beginning of year $ 12.7 $ 2.0 $ 2.5 Acquired through acquisitions — 15.8 — Additions 8.3 0.4 0.9 Valuation adjustments (1.1) (2.8) — Dispositions (3.4) (2.7) (1.4) Balance at end of year $ 16.5 $ 12.7 $ 2.0

Mortgage Servicing Rights (Tabl

Mortgage Servicing Rights (Tables)	12 Months Ended
	Dec. 31, 2023
Transfers and Servicing [Abstract]
Schedule of Servicing Assets at Amortized Value	Information with respect to the Company’s mortgage servicing rights follows: Year Ended December 31, 2023 2022 2021 Balance at beginning of year $ 31.1 $ 31.6 $ 34.3 Acquisition of mortgage servicing rights — 1.3 — Originations of mortgage servicing rights 1.1 2.5 3.7 Amortization expense (3.9) (4.3) (6.4) Balance at end of year 28.3 31.1 31.6 Less valuation reserve — — (3.4) Balance at end of year, net of valuation reserve $ 28.3 $ 31.1 $ 28.2 Principal balance of serviced loans underlying mortgage servicing rights $ 3,091.1 $ 3,259.8 $ 3,203.7 Mortgage servicing rights as a percentage of serviced loans 0.92 % 0.95 % 0.88 %

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2023
Deposits [Abstract]
Schedule of Deposits, By Type	Deposits are summarized as follows: December 31, 2023 2022 Non-interest bearing demand $ 6,029.6 $ 7,560.0 Interest bearing: Demand 6,507.8 7,205.9 Savings 7,775.8 8,379.3 Time, $250 and over 811.6 438.0 Time, other 2,198.3 1,490.4 Total interest bearing 17,293.5 17,513.6 Total deposits $ 23,323.1 $ 25,073.6
Schedule of Maturities of Time Deposits	Maturities of time deposits at December 31, 2023 are as follows: Time, $250 Total Time Due within 3 months or less $ 219.7 $ 770.4 Due after 3 months and within 6 months 233.9 854.0 Due after 6 months and within 12 months 279.5 1,024.3 Due within 2025 62.8 277.1 Due within 2026 9.1 48.2 Due within 2027 4.9 28.4 Due within 2028 and thereafter 1.7 7.5 Total $ 811.6 $ 3,009.9

Long-Term Debt and Other Borr_2

Long-Term Debt and Other Borrowed Funds (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Summary of Long-Term Debt	A summary of long-term debt follows: December 31, 2023 2022 Parent Company: Fixed to floating subordinated notes, 5.25% fixed rate effective May 2020 through May 2025 $ 99.0 $ 98.9 Subsidiaries: 8.00% finance lease obligation with term ending October 31, 2029 0.9 1.0 1.00% note payable maturing December 31, 2041, interest only payable quarterly until September 30, 2024 and then principal and interest until maturity 5.1 5.1 Note payable maturing March 31, 2038, interest only payable at 1.30% monthly until March 31, 2025 and then principal and interest at 3.25% until maturity 2.0 2.0 1.30% note payable maturing June 1, 2034, interest only payable monthly until March 31, 2025 and then principal and interest until maturity 0.6 0.6 1.12% note payable maturing December 31, 2045, interest only payable annually until December 31, 2028 and then principal and interest until maturity 6.8 6.8 1.35% note payable maturing December 31, 2046 interest only payable annually until December 31, 2025 and then principal and interest until maturity 6.4 6.4 Total long-term debt $ 120.8 $ 120.8
Schedule of Maturities of Long-term Debt	Maturities of long-term debt at December 31, 2023 were as follows: 2024 $ 0.1 2025 0.1 2026 0.1 2027 0.2 2028 0.2 Thereafter 120.1 Total $ 120.8

Regulatory Capital (Tables)

Regulatory Capital (Tables)	12 Months Ended
	Dec. 31, 2023
Banking Regulation, Risk-Based Information [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The Company’s actual capital amounts and ratios and selected minimum regulatory thresholds and prompt corrective action provisions as of December 31, 2023 and 2022 are presented in the following tables: Actual Minimum Required for Capital Adequacy Purposes For Capital Adequacy Purposes Plus Capital Conservation Buffer (1) Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements (2) December 31, 2023 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 2,941.1 13.28 % $ 1,771.6 8.00 % $ 2,325.2 10.50 % $ 2,214.5 10.00 % FIB 2,662.0 12.04 1,768.3 8.00 2,320.8 10.50 2,210.3 10.00 Tier 1 risk-based capital: Consolidated 2,454.4 11.08 1,328.7 6.00 1,882.3 8.50 1,771.6 8.00 FIB 2,433.0 11.01 1,326.2 6.00 1,878.8 8.50 1,768.3 8.00 Common equity tier 1 risk-based capital: Consolidated 2,454.4 11.08 996.5 4.50 1,550.1 7.00 1,439.4 6.50 FIB 2,433.0 11.01 994.6 4.50 1,547.2 7.00 1,436.7 6.50 Leverage capital ratio: Consolidated 2,454.4 8.22 1,193.9 4.00 1,193.9 4.00 1,492.3 5.00 FIB 2,433.0 8.16 1,192.2 4.00 1,192.2 4.00 1,490.2 5.00 December 31, 2022 Amount Ratio Amount Ratio Amount Ratio Amount Ratio Total risk-based capital: Consolidated $ 2,875.8 12.48 % $ 1,843.2 8.00 % $ 2,419.2 10.50 % $ 2,304.0 10.00 % FIB 2,713.5 11.80 1,839.6 8.00 2,414.5 10.50 2,299.5 10.00 Tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,382.4 6.00 1,958.4 8.50 1,843.2 8.00 FIB 2,504.1 10.89 1,379.7 6.00 1,954.6 8.50 1,839.6 8.00 Common equity tier 1 risk-based capital: Consolidated 2,408.8 10.45 1,036.8 4.50 1,612.8 7.00 1,497.6 6.50 FIB 2,504.1 10.89 1,034.8 4.50 1,609.7 7.00 1,494.7 6.50 Leverage capital ratio: Consolidated 2,408.8 7.75 1,242.9 4.00 1,242.9 4.00 1,553.6 5.00 FIB 2,504.1 8.07 1,241.1 4.00 1,241.1 4.00 1,551.4 5.00 (1) The capital conservation buffer is an additional 2.5% of the amount necessary to meet the minimum risk-based capital requirements for total, tier 1, and common equity tier 1 risk-based capital. (2) The ratios to meet the requirements to be deemed “well-capitalized” are only applicable to FIB. However, the Company manages its capital position as if the requirements apply to the consolidated company and has presented the ratios as if they also applied on a consolidated basis

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The total future minimum rental commitments, exclusive of maintenance and operating costs, required under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2023, are as follows: Third Parties Related Entity Total For the year ending December 31: 2024 $ 10.2 $ 1.4 $ 11.6 2025 8.5 1.4 9.9 2026 7.2 0.9 8.1 2027 5.4 0.1 5.5 2028 4.2 — 4.2 Thereafter 11.3 — 11.3 Total $ 46.8 $ 3.8 $ 50.6

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	Income tax expense consists of the following: Year ended December 31, 2023 2022 2021 Current: Federal $ 46.1 $ 45.2 $ 39.4 State 12.8 14.4 11.3 Total current 58.9 59.6 50.7 Deferred: Federal 16.0 (3.7) 3.7 State 4.4 (1.0) 1.3 Total deferred 20.4 (4.7) 5.0 Total income tax expense $ 79.3 $ 54.9 $ 55.7
Schedule of Effective Income Tax Rate Reconciliation	Total income tax provision differs from the amount of income tax determined by applying the statutory federal income tax rate of 21% for the periods presented to income before income taxes due to the following: Year ended December 31, 2023 2022 2021 Tax expense at the statutory tax rate $ 70.7 $ 54.0 $ 52.0 Increase (decrease) in tax resulting from: Tax-exempt income (8.1) (8.4) (2.8) State income tax, net of federal income tax benefit 13.6 10.6 9.9 Deficiency (benefit) of stock-based compensation plans 0.3 0.2 (0.5) Nondeductible transaction costs — 2.0 0.8 Federal tax credits (0.2) (4.3) (4.3) FDIC premiums 2.0 1.6 — Other, net 1.0 (0.8) 0.6 Tax expense at effective tax rate $ 79.3 $ 54.9 $ 55.7
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences between the financial statement carrying amounts and tax bases of assets and liabilities that give rise to significant portions of the net deferred tax asset (liability) relate to the following: December 31, 2023 2022 Deferred tax assets: Loans, principally due to allowance for credit losses $ 56.7 $ 54.8 Loan discount 21.7 32.5 Investment securities, unrealized losses 118.1 157.9 Derivatives, unrealized losses 0.3 0.5 Deferred compensation 18.6 26.8 Non-performing loan interest 2.2 2.6 Other real estate owned write-downs and carrying costs 1.4 1.5 Net operating loss carryforwards (1) 1.1 1.5 Lease liabilities 11.0 12.0 Other reserves 10.7 8.8 Contract incentives 7.5 8.5 Discount on acquired investment securities 10.1 13.4 Other 4.8 2.4 Deferred tax assets $ 264.2 $ 323.2 December 31, 2023 2022 Deferred tax liabilities: Fixed assets, principally differences in bases and depreciation $ (19.8) $ (17.3) Deferred loan costs (4.1) (3.3) Investment in joint venture partnership, principally due to differences in depreciation of partnership assets (2.4) (1.3) Right of use assets (10.3) (11.3) Prepaid amounts (0.9) (0.9) Government agency stock dividends (1.3) (1.2) Goodwill and other intangibles (68.1) (68.2) Mortgage servicing rights (6.9) (7.4) Other (0.4) (1.8) Deferred tax liabilities (114.2) (112.7) Net deferred tax assets $ 150.0 $ 210.5 (1) As of December 31, 2023, the Company had remaining federal net operating loss carryforwards of $2.4 million from acquired companies, which is available to offset federal taxable income and state net operating loss carryforwards in amounts which vary by state. The federal net operating losses will expire beginning in 2030 and ending in 2036 and the state net operating losses will expire beginning in 2023 and ending in 2036. The use of these carryforwards is subject to annual limitations.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	The following table presents information regarding the Company’s restricted stock: As of December 31, 2023 Number of Weighted-Average Restricted stock, beginning of year 741,098 $ 38.94 Granted 683,574 19.84 Vested (180,587) 36.73 Forfeited (127,779) 29.75 Restricted stock, end of year 1,116,306 $ 27.74

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Schedule of Comprehensive Income (Loss)	The gross amounts of each component of other comprehensive (loss) income and the related tax effects for the periods indicated are as follows: Year Ended December 31, 2023 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized gain during period $ 144.8 $ 36.1 $ 108.7 Reclassification adjustment for net losses included in net income 23.5 5.8 17.7 Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale (7.2) (1.8) (5.4) Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity (1.3) (0.3) (1.0) Change in net unrealized gain on derivatives 0.9 0.3 0.6 Total other comprehensive income $ 160.7 $ 40.1 $ 120.6 Year Ended December 31, 2022 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (613.1) $ (152.4) $ (460.7) Reclassification adjustment for net losses included in net income 24.4 5.5 18.9 Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale 0.2 0.1 0.1 Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity (26.1) (6.6) (19.5) Change in net unrealized loss on derivatives (6.7) (1.8) (4.9) Total other comprehensive loss $ (621.3) $ (155.2) $ (466.1) Year Ended December 31, 2021 Before Tax Amount Tax Expense (Benefit) Net of Tax Amount Investment securities available-for sale: Change in net unrealized loss during period $ (113.7) $ (28.7) $ (85.0) Reclassification adjustment for net gains included in net income (1.1) (0.3) (0.8) Net change in unamortized gains on available-for-sale securities transferred into held-to-maturity 20.2 5.1 15.1 Change in net unrealized loss on derivatives 4.2 1.1 3.1 Total other comprehensive loss $ (90.4) $ (22.8) $ (67.6)
Schedule of Accumulated Other Comprehensive Income (Loss)	The components of accumulated other comprehensive loss, net of income taxes, are as follows: Years ended December 31, 2023 2022 Net unrealized loss on investment securities available-for-sale $ (350.1) $ (471.0) Net unrealized (loss) gain on investment securities transferred to held-to-maturity (5.6) (4.5) Net unrealized (loss) gain on derivatives (0.8) (1.6) Net accumulated other comprehensive loss $ (356.5) $ (477.1)

Condensed Financial Informati_2

Condensed Financial Information (Parent Company Only) (Tables)	12 Months Ended
	Dec. 31, 2023
Condensed Financial Information Disclosure [Abstract]
Schedule of Condensed Financial Statements	Following is condensed financial information of First Interstate BancSystem, Inc. December 31, 2023 2022 Condensed balance sheets: Cash and cash equivalents $ 275.7 $ 154.8 Investment in bank subsidiary 3,062.2 2,985.8 Advances to subsidiaries, net 43.5 0.1 Other assets 147.0 240.7 Total assets $ 3,528.4 $ 3,381.4 Other liabilities $ 38.8 $ 45.6 Long-term debt 99.0 98.9 Subordinated debentures held by subsidiary trusts 163.1 163.1 Total liabilities 300.9 307.6 Stockholders’ equity 3,227.5 3,073.8 Total liabilities and stockholders’ equity $ 3,528.4 $ 3,381.4 Years Ended December 31, 2023 2022 2021 Condensed statements of income: Dividends from subsidiaries $ 360.0 $ 360.0 $ 160.0 Other interest income 0.5 0.4 — Other income, primarily management fees from subsidiaries 51.6 51.7 41.3 Total income 412.1 412.1 201.3 Salaries and benefits 34.5 40.6 36.4 Interest expense 18.4 12.6 8.2 Acquisition related expenses — 62.3 11.6 Other operating expenses, net 22.5 25.0 17.6 Total expenses 75.4 140.5 73.8 Earnings before income tax benefit 336.7 271.6 127.5 Income tax benefit (4.2) (18.9) (7.6) Income before undistributed earnings of subsidiaries 340.9 290.5 135.1 Undistributed (loss) earnings of subsidiaries (83.4) (88.3) 57.0 Net income $ 257.5 $ 202.2 $ 192.1 Years Ended December 31, 2023 2022 2021 Condensed statements of cash flows: Cash flows from operating activities: Net income $ 257.5 $ 202.2 $ 192.1 Adjustments to reconcile net income to cash provided by operating activities: Undistributed losses (earnings) of subsidiaries 83.4 88.3 (57.0) Stock-based compensation expense 4.6 9.6 8.9 Other, net 2.7 (151.2) (3.2) Net cash provided by operating activities 348.2 148.9 140.8 Cash flows from investing activities: Acquisition of bank holding company, net of cash and cash equivalents received — (0.8) — Net cash used in investing activities $ — $ (0.8) $ — Years Ended December 31, 2023 2022 2021 Cash flows from financing activities: Net increase in advances from subsidiaries $ 1.8 $ 206.5 $ 23.7 Proceeds from issuance of common stock, net of stock issuance costs — 0.1 0.4 Purchase and retirement of common stock (34.0) (198.9) (5.4) Dividends paid to common stockholders (195.1) (182.1) (101.6) Net cash used in financing activities (227.3) (174.4) (82.9) Net change in cash and cash equivalents 120.9 (26.3) 57.9 Cash and cash equivalents, beginning of year 154.8 181.1 123.2 Cash and cash equivalents, end of year $ 275.7 $ 154.8 $ 181.1

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and financial liabilities measured at fair value on a recurring basis are as follows: Fair Value Measurements at Reporting Date Using As of December 31, 2023 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 224.7 $ — $ 224.7 $ — State, county, and municipal securities 219.8 — 219.8 — Obligations of U.S. government agencies 168.5 — 168.5 — U.S. agency commercial mortgage-backed securities 1,105.6 — 1,105.6 — U.S. agency residential mortgage-backed securities 1,366.9 — 1,366.9 — Collateralized mortgage obligations 1,189.5 — 1,189.5 — Private mortgage-backed securities 210.4 — 210.4 — Collateralized loan obligations 1,119.7 — 1,119.7 — Corporate securities 236.4 — 236.4 — Loans held for sale 0.5 — 0.5 — Derivative assets: Interest rate swap contracts 37.3 — 37.3 — Interest rate lock commitments 0.1 — 0.1 — Derivative liabilities: Interest rate collars 3.6 — 3.6 — Interest rate swap contracts 123.5 — 123.5 — Risk participation agreements 0.1 — 0.1 — Forward loan sales contracts 0.1 — 0.1 — Deferred compensation plan assets 19.2 — 19.2 — Deferred compensation plan liabilities 19.2 — 19.2 — Fair Value Measurements at Reporting Date Using As of December 31, 2022 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment debt securities available-for-sale: U.S. Treasury notes $ 642.7 $ — $ 642.7 $ — State, county, and municipal securities 263.7 — 263.7 — Obligations of U.S. government agencies 198.9 — 198.9 — U.S. agency commercial mortgage-backed securities 1,351.2 — 1,351.2 — U.S. agency residential mortgage-backed securities 1,558.3 — 1,558.3 — Collateralized mortgage obligations 1,350.2 — 1,350.2 — Private mortgage-backed securities 228.0 — 228.0 — Collateralized loan obligations 1,111.6 — 1,111.6 — Corporate securities 241.5 — 241.5 — Loans held for sale 12.4 — 6.9 5.5 Derivative assets: Interest rate swap contracts 45.1 — 45.1 — Forward loan sales contracts 0.1 — 0.1 — Derivative liabilities: Interest rate collars 5.4 — 5.4 — Interest rate swap contracts 154.2 — 154.2 — Deferred compensation plan assets 18.7 — 18.7 — Deferred compensation plan liabilities 18.7 — 18.7 —
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Non-Recurring Basis	The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis: Fair Value Measurements at Reporting Date Using As of December 31, 2023 Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Collateral-dependent loans $ 52.6 $ — $ — $ 52.6 Loans held for sale 46.9 — — 46.9 Other real estate owned 16.5 — — 16.5 Long-lived assets to be disposed of by sale 1.0 — — 1.0 Fair Value Measurements at Reporting Date Using As of December 31, 2022 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Collateral-dependent loans $ 39.1 $ — $ — $ 39.1 Loans held for sale 67.5 — — 67.5 Other real estate owned 12.7 — — 12.7 Long-lived assets to be disposed of by sale 5.5 — — 5.5
Fair Value Inputs, Assets, Quantitative Information	The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values: As of December 31, 2023 Fair Value Valuation Technique Unobservable Inputs Range (Weighted Average) Collateral-dependent loans $ 52.6 Appraisal Appraisal adjustment —% - 100% (36%) Loans held for sale 46.9 Fair value of collateral Discount for type of property, age of appraisal, and current status 5% - 23% (14)% Other real estate owned 16.5 Appraisal Appraisal adjustment 10% - 43% (48)% Long-lived assets to be disposed of by sale 1.0 Appraisal Appraisal adjustment —% - —% —% As of December 31, 2022 Collateral-dependent loans $ 39.1 Appraisal Appraisal adjustment 0% - 45% (7%) Loans held for sale 67.5 Fair value of collateral Discount for type of property, age of appraisal, and current status 11% 23% (17%) Other real estate owned 12.7 Appraisal Appraisal adjustment 15% - 36% (22%) Long-lived assets to be disposed of by sale 5.5 Appraisal Appraisal adjustment 0% - 6% (3%)
Fair Value, by Balance Sheet Grouping	The estimated fair values of financial instruments that are reported in the Company’s consolidated balance sheets, and are segregated by the level of the valuation inputs within the fair value hierarchy that are utilized to measure fair value, are as follows: ` Fair Value Measurements at Reporting Date Using As of December 31, 2023 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Financial assets: Cash and cash equivalents $ 578.0 $ 578.0 $ 578.0 $ — $ — Investment debt securities available-for-sale 5,841.5 5,841.5 — 5,841.5 — Investment debt securities held-to-maturity 3,207.9 2,874.0 — 2,874.0 — Accrued interest receivable 129.1 129.1 — 129.1 — Mortgage servicing rights, net 28.3 38.8 — 38.8 — Loans held for sale 47.4 47.4 — 0.5 46.9 Net loans held for investment 18,051.9 17,334.4 — 17,281.8 52.6 Derivative assets 37.4 37.4 — 37.4 — Deferred compensation plan assets 19.2 19.2 — 19.2 — Total financial assets $ 27,940.7 $ 26,899.8 $ 578.0 $ 26,222.3 $ 99.5 Financial liabilities: Total deposits, excluding time deposits $ 20,313.2 $ 20,313.2 $ 20,313.2 $ — $ — Time deposits 3,009.9 2,981.7 — 2,981.7 — Securities sold under repurchase agreements 782.7 782.7 — 782.7 — Other borrowed funds 2,603.0 2,603.0 — 2,603.0 — Accrued interest payable 52.2 52.2 — 52.2 — Long-term debt 120.8 115.6 — 115.6 — Subordinated debentures held by subsidiary trusts 163.1 151.1 — 151.1 — Derivative liabilities 127.3 127.3 — 127.3 — Deferred compensation plan liabilities 19.2 19.2 — 19.2 — Total financial liabilities $ 27,191.4 $ 27,146.0 $ 20,313.2 $ 6,832.8 $ — Fair Value Measurements at Reporting Date Using As of December 31, 2022 Carrying Amount Estimated Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 870.5 $ 870.5 $ 870.5 $ — $ — Investment debt securities available-for-sale 6,946.1 6,946.1 — 6,946.1 — Investment debt securities held-to-maturity 3,451.8 3,052.2 — 3,052.2 — Accrued interest receivable 118.3 118.3 — 118.3 — Mortgage servicing rights, net 31.1 37.4 — 37.4 — Loans held for sale 79.9 79.9 — 6.9 73.0 Net loans held for investment 17,879.1 17,552.1 — 17,513.0 39.1 Derivative assets 45.2 45.2 — 45.2 — Deferred compensation plan assets 18.7 18.7 — 18.7 — Total financial assets $ 29,440.7 $ 28,720.4 $ 870.5 $ 27,737.8 $ 112.1 Financial liabilities: Total deposits, excluding time deposits $ 23,145.2 $ 23,145.2 $ 23,145.2 $ — $ — Time deposits 1,928.4 1,876.1 — 1,876.1 — Securities sold under repurchase agreements 1,052.9 1,052.9 — 1,052.9 — Other borrowed funds 2,327.0 2,327.0 — 2,327.0 — Accrued interest payable 14.5 14.5 — 14.5 — Long-term debt 120.8 116.3 — 116.3 — Subordinated debentures held by subsidiary trusts 163.1 155.8 — 155.8 — Derivative liabilities 159.6 159.6 — 159.6 — Deferred compensation plan liabilities 18.7 18.7 — 18.7 — Total financial liabilities $ 28,930.2 $ 28,866.1 $ 23,145.2 $ 5,720.9 $ —

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) segment subsidiary	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Property, Plant and Equipment
Deficiency (benefit) of stock-based compensation plans	$ 300,000	$ 200,000	$ (500,000)
Impairment losses	$ 0	0	0
Number of significant subsidiaries | subsidiary	1
Income tax examination, penalties	$ 0	0	0
Cash on deposit with Federal Reserve Bank	199,000,000	518,900,000
Federal Reserve Bank stock	94,200,000	93,600,000
Federal Home Loan Bank stock	127,800,000	103,800,000
Advertising expense	900,000	3,800,000	$ 2,600,000
Loans and Leases Receivable Disclosure [Line Items]
Accrued interest receivable	129,100,000	118,300,000
Accrued Investment Income Receivable	38,500,000	38,900,000
Hosting Arrangement, Service Contract, Implementation Cost, Expense, Amortization	$ 2,300,000	3,400,000
Number of operating segments | segment	1
Total investment securities	$ 1,200,000	1,200,000
Buildings and improvements | Minimum
Property, Plant and Equipment
Estimated useful lives	5 years
Buildings and improvements | Maximum [Member]
Property, Plant and Equipment
Estimated useful lives	45 years
Furniture and equipment | Minimum
Property, Plant and Equipment
Estimated useful lives	3 years
Furniture and equipment | Maximum [Member]
Property, Plant and Equipment
Estimated useful lives	15 years
Loans
Loans and Leases Receivable Disclosure [Line Items]
Accrued interest receivable	$ 86,100,000	$ 76,500,000

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 01, 2022 USD ($) office $ / shares shares	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Net		$ 81.4	$ 97
Goodwill		$ 1,100.9	1,100.9	$ 621.6
Number of operating segments | segment		1
Finite-lived intangible assets acquired			72.9
Estimated useful lives of related deposits		12 years
Acquisition related expenses		$ 0	118.9	11.6
Core Deposits Intangibles
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Net		$ 62.2	75.9
Finite-lived intangible assets acquired			50.1
Estimated useful lives of related deposits	10 years	10 years
Great Western Bank
Business Acquisition [Line Items]
Core deposit intangible assets	$ 50.1
Number of banking offices | office	174
Total consideration paid	$ 1,723.3
Goodwill	479.3
Great Western Bank | First Interstate Foundation
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Costs	21.5
Great Western Bank | Scott Family
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Costs	$ 8.2
Great Western Bank | Class A Common Stock
Business Acquisition [Line Items]
Common stock issued (in shares) | shares	46,879,601
Business Acquisition, Share Price | $ / shares	$ 36.76
Great Western Bank | Customer Relationships
Business Acquisition [Line Items]
Estimated useful lives of related deposits	12 years
Acquisition Related Costs as Defined by ASC 805
Business Acquisition [Line Items]
Acquisition related expenses			$ 26.8	$ 9

Acquisitions - Schedule of Reco

Acquisitions - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Feb. 01, 2022 USD ($) office $ / shares shares	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 1,100,900	$ 1,100,900	$ 621,600
Estimated useful lives of related deposits		12 years
Number of operating segments | segment		1
Great Western Bank
Business Acquisition [Line Items]
Number of banking offices | office	174
Cash and cash equivalents	$ 2,006,900
Business Combination, Recognized Identifiable Assets Acquirede and Liablilities Assumed, Current Assets, Securities Purchased Under Agreement to Resell	101,100
business combinatios, recognized identifiable assets acquired and liabilities assumed, loans held	217,000
Investment securities	2,699,000
Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Assumed, Loans Held for Investment	7,705,000
Business Combinations, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans and Leases Receivable, Allowance	(59,500)
Premises and equipment	144,700
Business Combinations, Recognized Identifiable Assests Acquired and Liabilities Assumed Other Real Estate Owned	15,800
Company owned life insurance	186,600
Core deposit intangible assets	50,100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	22,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Mortgage Servicing Rights	1,300
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets	60,200
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Assets	200,800
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Accounts Payable And Accrued Expense	110,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Federal Home Loan Bank Advances	122,900
Total assets acquired	13,351,800
Deposits	11,688,000
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Liabilities	36,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities	76,100
Total liabilities assumed	12,107,800
Net assets acquired	1,244,000
Class A common stock	1,723,300
Total consideration paid	1,723,300
Goodwill	479,300
Buisness Combination, Recognizable Assets Acquired and Liabilities Assumed, Securities Sold Under Repurchase Agreement	74,000
Business Combination, Consideration Paid in Lieu of Fractional Shares	13
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 31,700
Great Western Bank | Class A Common Stock
Business Acquisition [Line Items]
Common stock issued (in shares) | shares	46,879,601
Business Acquisition, Share Price | $ / shares	$ 36.76
Core Deposits Intangibles
Business Acquisition [Line Items]
Estimated useful lives of related deposits	10 years	10 years

Acquisitions - Schedule of Acqu

Acquisitions - Schedule of Acquisition Related Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Combinations [Abstract]
Acquisition related expenses	$ 0	$ 118.9	$ 11.6

Acquisitions - Schedules of Loa

Acquisitions - Schedules of Loans Acquired (Details) $ in Millions	Feb. 01, 2022 USD ($)
Business Acquisition [Line Items]
Certain Loans Acquired in Transfer Accounted for as Available-for-Sale Debt Securities, Accrued Interest	$ (18.1)
Purchase Price (Initial Fair Value)	623.3
Great Western Bank
Business Acquisition [Line Items]
Contractually required principal and interest payments	979.2
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Other-than-Temporary Impairment Charges, Credit Loss	238.7
Contractual cash flows not expected to be collected (“non-accretable discount”)	29.9
Purchase Price (Initial Fair Value)	623.3
Interest component of cash flows expected to be collected (“accretable discount”)	(69.2)
Fair value of acquired credit-impaired loans	682.8
Contractually required principal and interest payments	7,107.9
Contractual cash flows not expected to be collected	9.2
Fair value at acquisition	7,022.2
Certain Loans Acquired in Transfer Accounted for as Available-for-sale Debt Securities, Acquired, at Acquisition, at Fair Value	$ 722.4

Acquisitions - Schedule of Unau

Acquisitions - Schedule of Unaudited Pro Forma Revenue and Income (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Estimated useful lives of related deposits		12 years
Business Acquisition, Pro Forma Earnings Per Share, Basic			$ 3.28	$ 2.24
Business Acquisition, Pro Forma Earnings Per Share, Diluted			$ 3.28	$ 2.24
Great Western Bank
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Revenue			$ 1,223.3	$ 1,200.9
Business Acquisition, Pro Forma Net Income (Loss)			$ 351.6	$ 243.3
Core Deposits Intangibles
Business Acquisition [Line Items]
Estimated useful lives of related deposits	10 years	10 years

Acquisitions - Schedule of Ac_2

Acquisitions - Schedule of Acquired Loans with Credit Impairment (Details) $ in Millions	Feb. 01, 2022 USD ($)
Business Acquisition [Line Items]
Purchase Price (Initial Fair Value)	$ 623.3
Allowance for loans losses	298.2
Great Western Bank
Business Combination and Asset Acquisition [Abstract]
Contractually required principal and interest payments	979.2
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Other-than-Temporary Impairment Charges, Credit Loss	(238.7)
Business Acquisition [Line Items]
Certain Loans Acquired in Transfer Accounted for as Available-for-sale Debt Securities, Acquired, at Acquisition, at Fair Value	722.4
Interest component of cash flows expected to be collected (“accretable discount”)	(69.2)
Contractual cash flows not expected to be collected (“non-accretable discount”)	(29.9)
Purchase Price (Initial Fair Value)	623.3
Allowance for loans losses	59.5
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value	682.8
Contractually required principal and interest payments	7,107.9
Loans Acquired in Transfer, Accretable Yield	76.5
Contractual cash flows not expected to be collected	(9.2)
Loans Acquired in Transfer at Acquisition Fair Value	7,022.2
Loans Acquired in Transfer, Amortized cost basis	$ 7,705

Goodwill and Core Deposit Int_3

Goodwill and Core Deposit Intangibles - Goodwill Narrative (Details) - USD ($) $ in Millions				12 Months Ended
	Jul. 01, 2023	Jul. 01, 2022	Feb. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Impairment of goodwill	$ 0	$ 0
Reductions due to sale of health savings accounts				$ 15.7	$ 15.9	$ 9.9
Estimated useful lives of related deposits				12 years
Core Deposits Intangibles
Goodwill [Line Items]
Estimated useful lives of related deposits			10 years	10 years

Goodwill and Core Deposit Int_4

Goodwill and Core Deposit Intangibles - Goodwill Carrying Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Net carrying value at beginning of period	$ 1,100.9	$ 621.6
Net carrying value at end of period	1,100.9	1,100.9
Goodwill, Acquired During Period	0	479.3
Goodwill	$ 1,100.9	$ 1,100.9

Goodwill and Core Deposit Int_5

Goodwill and Core Deposit Intangibles - Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2021
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Gross	$ 177.5		$ 106
Finite-lived intangible assets acquired	72.9
Finite-Lived Intangible Assets, Period Increase (Decrease)	(1.4)
Finite-Lived Intangible Assets, Accumulated Amortization	(80.5)	$ (96.1)
Finite-Lived Intangible Assets, Net	97	81.4
Core Deposits Intangibles
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Gross	154.7		106
Finite-lived intangible assets acquired	50.1
Finite-Lived Intangible Assets, Period Increase (Decrease)	(1.4)
Finite-Lived Intangible Assets, Accumulated Amortization	(78.8)	(92.5)
Finite-Lived Intangible Assets, Net	75.9	62.2
OCRI
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Gross	22.8		$ 0
Finite-lived intangible assets acquired	22.8
Finite-Lived Intangible Assets, Period Increase (Decrease)	0
Finite-Lived Intangible Assets, Accumulated Amortization	(1.7)	(3.6)
Finite-Lived Intangible Assets, Net	$ 21.1	$ 19.2

Goodwill and Core Deposit Int_6

Goodwill and Core Deposit Intangibles - Schedule of Future Estimated CDI Amortization Expense (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
2023	$ 14.6
2024	13.7
2025	12.8
2026	10.1
2027	7.6
Thereafter	22.6
Finite-Lived Intangible Assets, Net	81.4	$ 97
Core Deposits Intangibles
Finite-Lived Intangible Assets [Line Items]
2023	12.7
2024	11.8
2025	10.9
2026	8.2
2027	5.7
Thereafter	12.9
Finite-Lived Intangible Assets, Net	62.2	75.9
OCRI
Finite-Lived Intangible Assets [Line Items]
2023	1.9
2024	1.9
2025	1.9
2026	1.9
2027	1.9
Thereafter	9.7
Finite-Lived Intangible Assets, Net	$ 19.2	$ 21.1

Investment Securities - Narrati

Investment Securities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Available-for-sale, Realized Loss	$ (23.5)	$ (46.8)	$ (2.1)
Debt Securities, Available-for-sale, Realized Gain	0	$ 0.3	$ 3.2
Debt Securities, Held-to-maturity, Nonaccrual	0
Debt Securities, Current	853
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis	1,603.3
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Fair Value	1,552.2
Collateral
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities	$ 0

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Approximate Fair Values of Investment Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available for Sale and Held-to-Maturity Securities
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost	$ 40.1
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis	1,603.3
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Fair Value	1,552.2
Available-for-Sale:
Gross Unrealized Gains	3.2	$ 2.3
Gross Unrealized Losses	(469.5)	(629.7)
Held-to-Maturity:
Debt Securities, Held-to-maturity	3,208.7	3,453.7
Allowance for Credit Losses	0.4	0.4
Gross Unrealized Losses	(334.3)	(400)
Held-to-maturity investment securities, estimated fair value	2,874	3,052.2
Debt Securities, Held-to-Maturity, Transfer, Unamortized Gain	10.7
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	39.4
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	309.1
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	307.5
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost	1,004.4
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	938.7
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	346.6
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	329.4
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost	1,373.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	1,255.4
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	654
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	579.1
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost	3,889.4
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	3,608
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost	1,899
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	1,658
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(0.8)	(1.9)	$ 0	$ 0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	3,207.9	3,451.8
Debt and Equity Securities, Unrealized Gain (Loss)	(18.1)	(20.2)
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	6,307.8	7,573.5
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	6,307.8	7,573.5
Debt Securities, Available-for-Sale, Excluding Accrued Interest	5,841.5	6,946.1
US Treasury notes
Available-for-Sale:
Gross Unrealized Gains	0	2.1
Gross Unrealized Losses	(25.5)	(34.5)
Held-to-Maturity:
Debt Securities, Held-to-maturity	399	396.6
Allowance for Credit Losses	0	0
Gross Unrealized Losses	(2.8)	(10.2)
Held-to-maturity investment securities, estimated fair value	396.2	386.4
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	399	396.6
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	250.2	675.1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	250.2	675.1
Debt Securities, Available-for-Sale, Excluding Accrued Interest	224.7	642.7
State, county and municipal securities
Available-for-Sale:
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(36.9)	(50.6)
Held-to-Maturity:
Debt Securities, Held-to-maturity	179.2	181.2
Allowance for Credit Losses	0.2	0.2
Gross Unrealized Losses	(24.2)	(31.6)
Held-to-maturity investment securities, estimated fair value	155.2	149.7
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	(0.1)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	179.2	181.1
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	256.7	314.3
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	256.7	314.3
Debt Securities, Available-for-Sale, Excluding Accrued Interest	219.8	263.7
US Government Agencies Debt Securities [Member]
Available-for-Sale:
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(10.9)	(17.3)
Held-to-Maturity:
Debt Securities, Held-to-maturity	354.5	351.7
Allowance for Credit Losses	0	0
Gross Unrealized Losses	(42.4)	(49.6)
Held-to-maturity investment securities, estimated fair value	312.1	302.1
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	354.5	351.7
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	179.4	216.2
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	179.4	216.2
Debt Securities, Available-for-Sale, Excluding Accrued Interest	168.5	198.9
Corporate Debt Securities [Member]
Available-for-Sale:
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(24.4)	(30.8)
Held-to-Maturity:
Debt Securities, Held-to-maturity	57	80.1
Allowance for Credit Losses	0	0
Gross Unrealized Losses	(6)	(7)
Held-to-maturity investment securities, estimated fair value	50.2	71.3
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(0.8)	(1.8)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	56.2	78.3
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	260.8	272.3
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	260.8	272.3
Debt Securities, Available-for-Sale, Excluding Accrued Interest	236.4	241.5
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-Sale:
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(30.9)	(36.9)
Held-to-Maturity:
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	241.3	264.9
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	241.3	264.9
Debt Securities, Available-for-Sale, Excluding Accrued Interest	210.4	228
Collateralized Loan Obligations
Available-for-Sale:
Gross Unrealized Gains	0.1	0
Gross Unrealized Losses	(2.3)	(33.6)
Held-to-Maturity:
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	1,121.9	1,145.2
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	1,121.9	1,145.2
Debt Securities, Available-for-Sale, Excluding Accrued Interest	1,119.7	1,111.6
Residential Mortgage-Backed Securities
Available-for-Sale:
Gross Unrealized Gains	1.2	0
Gross Unrealized Losses	(130.6)	(167.7)
Held-to-Maturity:
Debt Securities, Held-to-maturity	1,232.6	1,391.5
Allowance for Credit Losses	0	0
Gross Unrealized Losses	(137)	(166.6)
Held-to-maturity investment securities, estimated fair value	1,095.6	1,224.9
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	1,232.6	1,391.5
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	1,496.3	1,726
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	1,496.3	1,726
Debt Securities, Available-for-Sale, Excluding Accrued Interest	1,366.9	1,558.3
Collateralized Mortgage Obligations
Available-for-Sale:
Gross Unrealized Gains	1.3	0
Gross Unrealized Losses	(120.3)	(141.3)
Held-to-Maturity:
Debt Securities, Held-to-maturity	475.9	525.8
Allowance for Credit Losses	0.2	0.2
Gross Unrealized Losses	(69)	(76.7)
Held-to-maturity investment securities, estimated fair value	407.1	449.3
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	475.9	525.8
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	1,308.5	1,491.5
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	1,308.5	1,491.5
Debt Securities, Available-for-Sale, Excluding Accrued Interest	1,189.5	1,350.2
Commercial Mortgage Backed Securities
Available-for-Sale:
Gross Unrealized Gains	0.6	0.2
Gross Unrealized Losses	(87.7)	(117)
Held-to-Maturity:
Debt Securities, Held-to-maturity	510.5	526.8
Allowance for Credit Losses	0	0
Gross Unrealized Losses	(52.9)	(58.3)
Held-to-maturity investment securities, estimated fair value	457.6	468.5
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	510.5	526.8
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	1,192.7	1,468
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss	1,192.7	1,468
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 1,105.6	1,351.2
US agency, residential and commercial MBS and CMOs
Held-to-Maturity:
Debt Securities, Held-to-Maturity, Transfer, Unamortized Gain		$ 14.2

Investment Securities - Gross U

Investment Securities - Gross Unrealized Losses and Fair Values of Investment Securities (Details) $ in Millions	Dec. 31, 2023 USD ($) Investments	Dec. 31, 2022 USD ($) Investments
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	$ 3,208.7	$ 3,453.7
Available-for-Sale and Held-to-Maturity:
Investment securities in an unrealized loss position (number of securities) | Investments	995	1,222
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 0.9	$ 5,071.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,505.5	1,545.6
Debt Securities, Available-for-sale, Unrealized Loss Position	5,506.4	6,617.5
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(469.5)	(629.7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(346.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(469.5)	(283.1)
US Government Agencies Debt Securities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	354.5	351.7
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	152.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	168	46.1
Debt Securities, Available-for-sale, Unrealized Loss Position	168	198.3
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(10.9)	(17.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(10.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(10.9)	(7.2)
Corporate Debt Securities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	57	80.1
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	130.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	236.5	110.8
Debt Securities, Available-for-sale, Unrealized Loss Position	236.5	241.4
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(24.4)	(30.8)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(8.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(24.4)	(22.5)
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	133.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	210.5	94.9
Debt Securities, Available-for-sale, Unrealized Loss Position	210.5	228
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(30.9)	(36.9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(19.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(30.9)	(17.8)
US Treasury notes
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	399	396.6
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	168.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	224.7	170.4
Debt Securities, Available-for-sale, Unrealized Loss Position	224.7	339.2
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(25.5)	(34.5)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(4.7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(25.5)	(29.8)
State, county and municipal securities
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	179.2	181.2
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	104.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	217.1	146.1
Debt Securities, Available-for-sale, Unrealized Loss Position	217.1	251
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(36.9)	(50.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(36.9)	(41.6)
Collateralized Loan Obligations
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	1,082.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	935.7	28.9
Debt Securities, Available-for-sale, Unrealized Loss Position	935.7	1,111.5
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(2.3)	(33.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(33.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2.3)	(0.5)
Commercial Mortgage Backed Securities
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	510.5	526.8
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0.2	1,069.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,083.1	270.8
Debt Securities, Available-for-sale, Unrealized Loss Position	1,083.3	1,340.6
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(87.7)	(116.9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(59.9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(87.7)	(57)
Residential Mortgage-Backed Securities
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	1,232.6	1,391.5
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0.7	1,213.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,287.5	344.6
Debt Securities, Available-for-sale, Unrealized Loss Position	1,288.2	1,558.1
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(130.6)	(167.7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(112.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(130.6)	(55.4)
Collateralized Mortgage Obligations
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	475.9	525.8
Available-for-Sale and Held-to-Maturity:
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	1,016.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,142.4	333
Debt Securities, Available-for-sale, Unrealized Loss Position	1,142.4	1,349.4
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(120.3)	(141.4)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(90.1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (120.3)	$ (51.3)

Investment Securities - Maturit

Investment Securities - Maturities of Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost	$ 40.1
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost	1,004.4
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost	1,373.9
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost	3,889.4
Debt Securities, Available-for-Sale, Excluding Accrued Interest	5,841.5	$ 6,946.1
Amortized Cost	6,307.8	7,573.5
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	39.4
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	938.7
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	1,255.4
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	3,608
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	309.1
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	346.6
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	654
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost	1,899
Amortized Cost1	3,208.7	3,453.7
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	307.5
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value	329.4
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value	579.1
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value	1,658
Estimated Fair Value	2,874	3,052.2
Available-for-sale Securities and Held-to-maturity Securities
Investment Securities, Primarily Classified As Available-For-Sale, Debt Maturities, Rolling Year Two Through Five, Fair Value	1,552.2
Securities sold under agreements to repurchase	3,858.6	4,998.9
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	$ 3,462.2	$ 4,432

Investment Securities - Held-to

Investment Securities - Held-to-Maturity Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 0.8	$ 1.9	$ 0	$ 0
Debt Securities, Held-to-maturity, Credit Loss Expense (Reversal)	(1.1)	1.9	$ 0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	$ 0	$ 0

Investment Securities - Credit

Investment Securities - Credit Quality Indicators (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 3,208.7	$ 3,453.7
AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	3,041.5	3,260.7
AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	92.3	92.8
A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	10.6	11.5
BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	47	65.1
BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	5	10
Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	12.3	13.6
US Treasury Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	399	396.6
US Treasury Securities [Member] | AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	399	396.6
US Treasury Securities [Member] | AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Treasury Securities [Member] | A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Treasury Securities [Member] | BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Treasury Securities [Member] | BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Treasury Securities [Member] | Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
State, county and municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	179.2	181.2
State, county and municipal securities | AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	69	68.3
State, county and municipal securities | AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	92.3	92.8
State, county and municipal securities | A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	10.6	11.5
State, county and municipal securities | BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
State, county and municipal securities | BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
State, county and municipal securities | Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	7.3	8.6
US Government Agencies Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	354.5	351.7
US Government Agencies Debt Securities [Member] | AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	354.5	351.7
US Government Agencies Debt Securities [Member] | AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Government Agencies Debt Securities [Member] | A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Government Agencies Debt Securities [Member] | BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Government Agencies Debt Securities [Member] | BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
US Government Agencies Debt Securities [Member] | Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	57	80.1
Corporate Debt Securities [Member] | AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member] | AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member] | A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Corporate Debt Securities [Member] | BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	47	65.1
Corporate Debt Securities [Member] | BB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	5	10
Corporate Debt Securities [Member] | Not Rated
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	5	5
Commercial Mortgage Backed Securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	510.5	526.8
Commercial Mortgage Backed Securities | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	359.7	364.9
Commercial Mortgage Backed Securities | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	150.8	161.9
Commercial Mortgage Backed Securities | AAA Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	359.7	364.9
Commercial Mortgage Backed Securities | AAA Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	150.8	161.9
Commercial Mortgage Backed Securities | AA Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | AA Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | A Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | A Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | BBB Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | BBB Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | BB Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | BB Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | Not Rated | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Commercial Mortgage Backed Securities | Not Rated | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,232.6	1,391.5
Residential Mortgage-Backed Securities | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,189.8	1,342.9
Residential Mortgage-Backed Securities | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	42.8	48.6
Residential Mortgage-Backed Securities | AAA Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,189.8	1,342.9
Residential Mortgage-Backed Securities | AAA Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	42.8	48.6
Residential Mortgage-Backed Securities | AA Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | AA Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | A Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | A Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | BBB Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | BBB Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | BB Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | BB Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | Not Rated | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Residential Mortgage-Backed Securities | Not Rated | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Collateralized Mortgage Obligations
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	475.9	525.8
Collateralized Mortgage Obligations | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	334.1	525.8
Collateralized Mortgage Obligations | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	141.8
Collateralized Mortgage Obligations | AAA Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	334.1	525.8
Collateralized Mortgage Obligations | AAA Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	141.8
Collateralized Mortgage Obligations | AA Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Collateralized Mortgage Obligations | AA Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Collateralized Mortgage Obligations | A Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Collateralized Mortgage Obligations | A Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Collateralized Mortgage Obligations | BBB Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Collateralized Mortgage Obligations | BBB Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Collateralized Mortgage Obligations | BB Rating | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	0
Collateralized Mortgage Obligations | BB Rating | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0
Collateralized Mortgage Obligations | Not Rated | FNMA and FHLMC
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	0	$ 0
Collateralized Mortgage Obligations | Not Rated | GNMA
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 0

Loans Held for Sale - Narrative

Loans Held for Sale - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	$ 47.4	$ 79.9
Amortization of unrealized gains and losses on transfers of securities	30.4	12.4	$ 0
Transfer of Loans Held-for-sale to Portfolio Loans	(29.6)	(19.8)	0
Transfer of loans to other real estate owned	8.3	0.4	$ 0.9
Non-accrual Loans	27.3	39.8
Agricultural Financing Receivable [Member]
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	19.6	62.5
Unpaid Principle Balance of Loans Held for Sale		7.7
Loans Held-for-sale, Fair Value Disclosure		5.5
Amortization of unrealized gains and losses on transfers of securities	0
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	2.2
Transfer of Loans Held-for-sale to Portfolio Loans	(29.6)
Transfer of loans to other real estate owned	0
Proceeds from Collection of Loans Held-for-sale	(15.5)
Proceeds from Sale of Loans Held-for-sale	0
Non-accrual Loans		29.3
Agricultural Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Schedule of Available-for-sale Securities
Unpaid Principle Balance of Loans Held for Sale		5.6
Agricultural Financing Receivable [Member] | Lower of Cost or Market
Schedule of Available-for-sale Securities
Loans held for sale		57
Real Estate Construction Financing Receivable [Member]
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	0	10.5
Amortization of unrealized gains and losses on transfers of securities	3.1
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	(4.1)
Transfer of Loans Held-for-sale to Portfolio Loans	0
Transfer of loans to other real estate owned	6.4
Proceeds from Collection of Loans Held-for-sale	0
Proceeds from Sale of Loans Held-for-sale	(3.1)
Non-accrual Loans		10.5
Commercial Real Estate
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	27.3	0
Amortization of unrealized gains and losses on transfers of securities	27.3
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	0
Transfer of Loans Held-for-sale to Portfolio Loans	0
Transfer of loans to other real estate owned	0
Proceeds from Collection of Loans Held-for-sale	0
Proceeds from Sale of Loans Held-for-sale	0
Commercial Portfolio Segment [Member]
Schedule of Available-for-sale Securities
Non-accrual Loans	11.5	10.2
Agricultural Financing Receivable [Member]
Schedule of Available-for-sale Securities
Non-accrual Loans	30.4	8.7
Agricultural Financing Receivable [Member]
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	19.6	62.5
Residential Real Estate
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	0.5	6.9
Real Estate Construction Financing Receivable [Member]
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	0	10.5
Commercial Real Estate
Schedule of Available-for-sale Securities
Loans Held for Sale (Table)	$ 27.3	$ 0

Loans Held for Investment - Sch

Loans Held for Investment - Schedule of Loans by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2020
Loans and Leases Receivable
Loans and Leases Receivable, Deferred Income	$ (15.6)	$ (12.5)
Loans and Leases Receivable, Net of Deferred Income	18,099.2	18,279.6
Accounts Receivable, Allowance for Credit Loss	(220.1)	(227.7)	$ (144.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	122.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(59.5)
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(74.6)		(54.8)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	43.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(37.6)
Loans and Leases Receivable, Collateral for Secured Borrowings	8,528.6	8,869.2
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(3.6)		(1.6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	2.4
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0
Commercial Real Estate Construction [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(31.2)		(7.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	6
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(0.2)
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings	1,944.4	1,826.5
Residential Mortgage [Member]
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings	2,188.3	2,244.3
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(5.9)		(2.7)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(2.3)
Loans and Leases Receivable, Collateral for Secured Borrowings	794.9	716.8
Real Estate Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(138.7)	(160.1)	(80.5)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	69.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(43.6)
Loans and Leases Receivable, Collateral for Secured Borrowings	13,456.2	13,656.8
Indirect consumer
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(15.3)		(16.7)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	14.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0
Loans and Leases Receivable, Collateral for Secured Borrowings	829.7	740.9
Other consumer
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(5.2)		(4.6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	4.6
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0
Loans and Leases Receivable, Collateral for Secured Borrowings	152.9	141.6
Credit card consumer
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(2.8)		(2.6)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	2.2
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0
Loans and Leases Receivable, Collateral for Secured Borrowings	75.9	76.5
Total consumer loans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(23.3)	(13)	(23.9)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	21.1
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0
Loans and Leases Receivable, Collateral for Secured Borrowings	1,058.5	959
Commercial Portfolio Segment [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(54.9)	(50.2)	(39.2)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	31.6
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(11.4)
Loans and Leases Receivable, Collateral for Secured Borrowings	2,882.6	2,906.8
Agricultural Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(3.2)	(4.4)	(0.7)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	0.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(4.5)
Loans and Leases Receivable, Collateral for Secured Borrowings	708.3	769.4
Other, including overdrafts
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings	9.2	0.1
Loans held for investment
Loans and Leases Receivable
Loans and Leases Receivable, Collateral for Secured Borrowings	18,114.8	$ 18,292.1
Non Owner Occupied Loans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(27.2)		(25.5)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	17.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(17.2)
Commercial Real Estate Owner Occupied
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(19.5)		(18.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	13.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(9.5)
Commercial Real Estate Multifamily
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(27.9)		(11)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	13.3
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(10.9)
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(1.3)		(1.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	0.5
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(3.4)
Construction Loans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(36.1)		(10.2)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	8.9
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(3.6)
Residential Real Estate 1-4 Family
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(20.5)		(11.4)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	13.4
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(0.1)
Home Equity Loan
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(1.6)		(1.4)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	1.2
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	0
Residential Real Estate
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(22.1)		(12.8)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	14.6
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(0.1)
Commercial and Floor Plans
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(49)		(34.2)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	27.1
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(11.2)
Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(5.7)		(4.7)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	4.4
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	(0.2)
Commercial Borrower
Loans and Leases Receivable
Accounts Receivable, Allowance for Credit Loss	(0.2)		$ (0.3)
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	0.1
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method	$ 0

Loans Held for Investment - S_2

Loans Held for Investment - Schedule of Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense	$ 32.2	$ 82.7	$ (14.6)
Less loans charged-off	(35.9)	(45)	(16.6)
Recoveries Collected	12.4	14.9	9.3
Accounts Receivable, Allowance for Credit Loss	227.7	220.1	122.3	$ 144.3
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	31.1	68.4	(14.7)
Non Owner Occupied Loans
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		(4.2)	(8.3)
Less loans charged-off		(3.5)	0
Recoveries Collected		0.4	0.1
Accounts Receivable, Allowance for Credit Loss		27.2	17.3	25.5
Commercial Real Estate Owner Occupied
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		(2.7)	(2.7)
Less loans charged-off		(2.5)	(2.3)
Recoveries Collected		1.9	0
Accounts Receivable, Allowance for Credit Loss		19.5	13.3	18.3
Commercial Real Estate Multifamily
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		8.7	2.3
Less loans charged-off		(5.7)	0
Recoveries Collected		0.7	0
Accounts Receivable, Allowance for Credit Loss		27.9	13.3	11
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		1.8	(8.7)
Less loans charged-off	(7.6)	(11.7)	(2.3)
Recoveries Collected		3	0.1
Accounts Receivable, Allowance for Credit Loss		74.6	43.9	54.8
Land Acquisition And Development Construction Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		(0.4)	(0.1)
Less loans charged-off		(2.6)	(1.2)
Recoveries Collected		0.4	0.5
Accounts Receivable, Allowance for Credit Loss		1.3	0.5	1.3
Residential Real Estate Construction Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		1.1	0.9
Less loans charged-off		0	(0.1)
Recoveries Collected		0.1	0
Accounts Receivable, Allowance for Credit Loss		3.6	2.4	1.6
Commercial Real Estate Construction [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		31.6	(1.3)
Less loans charged-off		(6.6)	(0.1)
Recoveries Collected		0	0.1
Accounts Receivable, Allowance for Credit Loss		31.2	6	7.3
Construction Loans
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		32.3	(0.5)
Less loans charged-off		(9.2)	(1.4)
Recoveries Collected		0.5	0.6
Accounts Receivable, Allowance for Credit Loss		36.1	8.9	10.2
Residential Real Estate 1-4 Family
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		6.9	2
Less loans charged-off		(0.2)	0
Recoveries Collected		0.3	0
Accounts Receivable, Allowance for Credit Loss		20.5	13.4	11.4
Residential Real Estate
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		6.9	1.6
Less loans charged-off	(0.6)	(0.3)	(0.1)
Recoveries Collected		0.8	0.3
Accounts Receivable, Allowance for Credit Loss		22.1	14.6	12.8
Agricultural Real Estate Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		1.5	(0.1)
Less loans charged-off	0	(0.2)	(0.7)
Recoveries Collected		0.4	0
Accounts Receivable, Allowance for Credit Loss		5.9	1.9	2.7
Real Estate Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense	35.2	42.5	(7.7)
Less loans charged-off	(18.5)	(21.4)	(4.5)
Recoveries Collected	4.7	4.7	1
Accounts Receivable, Allowance for Credit Loss	160.1	138.7	69.3	80.5
Indirect consumer
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		2.7	(1.4)
Less loans charged-off	(7.3)	(4)	(3.5)
Recoveries Collected		2.3	2.5
Accounts Receivable, Allowance for Credit Loss		15.3	14.3	16.7
Other consumer
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		2.2	1.7
Less loans charged-off	(4.1)	(3.7)	(2.9)
Recoveries Collected		2.1	1.2
Accounts Receivable, Allowance for Credit Loss		5.2	4.6	4.6
Credit card consumer
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		2.4	0.6
Less loans charged-off	(2.6)	(2.4)	(1.8)
Recoveries Collected		0.6	0.8
Accounts Receivable, Allowance for Credit Loss		2.8	2.2	2.6
Total consumer loans
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense	(1)	7.3	0.9
Less loans charged-off	(14)	(10.1)	(8.2)
Recoveries Collected	4.7	5	4.5
Accounts Receivable, Allowance for Credit Loss	13	23.3	21.1	23.9
Commercial and Floor Plans
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		15.1	(7.3)
Less loans charged-off		(6.6)	(3)
Recoveries Collected		2.2	3.2
Accounts Receivable, Allowance for Credit Loss		49	27.1	34.2
Commercial Purpose Secured by 1-4 Family
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		1.2	(0.5)
Less loans charged-off		(0.2)	(0.3)
Recoveries Collected		0.1	0.5
Accounts Receivable, Allowance for Credit Loss		5.7	4.4	4.7
Commercial Borrower
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		1.4	0.1
Less loans charged-off		(1.3)	(0.4)
Recoveries Collected		0	0.1
Accounts Receivable, Allowance for Credit Loss		0.2	0.1	0.3
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense	(3.9)	17.7	(7.7)
Less loans charged-off	(3.4)	(8.1)	(3.7)
Recoveries Collected	2.6	2.3	3.8
Accounts Receivable, Allowance for Credit Loss	50.2	54.9	31.6	39.2
Agricultural Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense	0.8	0.9	(0.2)
Less loans charged-off	0	(5.4)	(0.2)
Recoveries Collected	0.4	2.9	0
Accounts Receivable, Allowance for Credit Loss	$ 4.4	3.2	0.3	0.7
Home Equity Loan
Financing Receivable, Allowance for Credit Losses
Provision charged (credited) to operating expense		0	(0.4)
Less loans charged-off		(0.1)	(0.1)
Recoveries Collected		0.5	0.3
Accounts Receivable, Allowance for Credit Loss		$ 1.6	$ 1.2	$ 1.4

Loans Held for Investment - S_3

Loans Held for Investment - Schedule of Contractual Aging of Loans by Portfolio (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	$ 6,700,000
Non-accrual Loans	27,300,000	$ 39,800,000
Loans and Leases Receivable, Nonperforming, Accrual of Interest	0
Impaired Financing Receivable, Interest Income, Accrual Method	0
Less loans charged-off	35,900,000	45,000,000	$ 16,600,000
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	28,200,000	19,600,000
Loans and Leases Receivable, Collateral for Secured Borrowings	8,869,200,000	8,528,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,337,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,085,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,675,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,215,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	774,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,706,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	47,000,000
Loans and Leases Receivable, Allowance	8,869,200,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	28,100,000
Less loans charged-off	7,600,000	11,700,000	2,300,000
Commercial Real Estate Portfolio Segment [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,268,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,065,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,612,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,200,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	716,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,660,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	46,500,000
Loans and Leases Receivable, Allowance	8,596,900,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	28,100,000
Commercial Real Estate Portfolio Segment [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	65,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	11,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	30,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	28,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	200,000
Loans and Leases Receivable, Allowance	157,300,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Commercial Real Estate Portfolio Segment [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	4,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	42,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	12,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	27,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	17,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	300,000
Loans and Leases Receivable, Allowance	113,700,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Commercial Real Estate Portfolio Segment [Member] | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Loans and Leases Receivable, Allowance	1,300,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	12,700,000	5,600,000
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	6,100,000	800,000
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	1,100,000
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	18,800,000	7,500,000
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	8,822,200,000	8,501,500,000
Commercial Real Estate Portfolio Segment [Member] | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	1,700,000
Commercial Real Estate Portfolio Segment [Member] | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	300,000
Commercial Real Estate Portfolio Segment [Member] | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	1,700,000
Commercial Real Estate Portfolio Segment [Member] | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	2,600,000
Commercial Real Estate Portfolio Segment [Member] | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Commercial Real Estate Portfolio Segment [Member] | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	1,300,000
Commercial Real Estate Portfolio Segment [Member] | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Commercial Real Estate Portfolio Segment [Member] | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		159,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		117,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		29,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		17,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		11,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		29,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		22,200,000
Loans and Leases Receivable, Allowance		386,200,000
Less loans charged-off		2,600,000	1,200,000
Land Acquisition And Development Construction Financing Receivable [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		152,500,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		114,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		29,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		17,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		10,900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		28,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		22,200,000
Loans and Leases Receivable, Allowance		374,900,000
Land Acquisition And Development Construction Financing Receivable [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		900,000
Land Acquisition And Development Construction Financing Receivable [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		6,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		7,200,000
Land Acquisition And Development Construction Financing Receivable [Member] | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		3,200,000
Financing Receivable, Originated in Current Fiscal Year		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		3,200,000
Financing Receivable, Originated Two Years before Latest Fiscal Year		0
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		0
Financing Receivable, Revolving		0
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		118,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		120,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		6,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		270,100,000
Loans and Leases Receivable, Allowance		516,200,000
Less loans charged-off		0	100,000
Residential Real Estate Construction Financing Receivable [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		118,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		119,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		5,800,000
Financing Receivable, Excluding Accrued Interest, Revolving		270,100,000
Loans and Leases Receivable, Allowance		515,300,000
Residential Real Estate Construction Financing Receivable [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		900,000
Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		461,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		399,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		112,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		45,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		21,900,000
Loans and Leases Receivable, Allowance		1,042,000,000
Less loans charged-off		6,600,000	100,000
Commercial Real Estate Construction [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		442,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		374,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		89,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		45,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		10,600,000
Loans and Leases Receivable, Allowance		964,100,000
Commercial Real Estate Construction [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		41,200,000
Financing Receivable, Originated in Current Fiscal Year		16,800,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		24,400,000
Financing Receivable, Originated Two Years before Latest Fiscal Year		0
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		0
Financing Receivable, Revolving		0
Commercial Real Estate Construction [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		36,700,000
Financing Receivable, Originated in Current Fiscal Year		2,300,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		0
Financing Receivable, Originated Two Years before Latest Fiscal Year		23,100,000
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		0
Financing Receivable, Revolving		11,300,000
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	17,200,000	3,700,000
Loans and Leases Receivable, Collateral for Secured Borrowings	1,826,500,000	1,944,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	501,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	758,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	356,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	36,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	16,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	36,800,000
Financing Receivable, Excluding Accrued Interest, Revolving	104,400,000
Loans and Leases Receivable, Allowance	1,826,500,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	14,600,000
Less loans charged-off	10,300,000
Real Estate Construction Financing Receivable [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	493,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	735,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	331,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	36,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	16,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	36,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	104,400,000
Loans and Leases Receivable, Allowance	1,768,000,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	13,700,000
Real Estate Construction Financing Receivable [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	4,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	24,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Loans and Leases Receivable, Allowance	36,000,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Real Estate Construction Financing Receivable [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	500,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	200,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Loans and Leases Receivable, Allowance	9,500,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	900,000
Real Estate Construction Financing Receivable [Member] | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	13,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Loans and Leases Receivable, Allowance	13,000,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Real Estate Construction Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,100,000	10,400,000
Real Estate Construction Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	400,000	600,000
Real Estate Construction Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	600,000
Real Estate Construction Financing Receivable [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,500,000	11,600,000
Real Estate Construction Financing Receivable [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,805,800,000	1,929,100,000
Real Estate Construction Financing Receivable [Member] | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Real Estate Construction Financing Receivable [Member] | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Real Estate Construction Financing Receivable [Member] | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Real Estate Construction Financing Receivable [Member] | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Real Estate Construction Financing Receivable [Member] | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	600,000
Real Estate Construction Financing Receivable [Member] | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Real Estate Construction Financing Receivable [Member] | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Real Estate Construction Financing Receivable [Member] | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	9,600,000
Residential Mortgage [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	10,700,000	6,400,000
Loans and Leases Receivable, Collateral for Secured Borrowings	2,244,300,000	2,188,300,000
Residential Mortgage [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	11,900,000	9,900,000
Residential Mortgage [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,100,000	2,100,000
Residential Mortgage [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	1,200,000
Residential Mortgage [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	15,600,000	13,200,000
Residential Mortgage [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,218,000,000	2,168,700,000
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	5,400,000	7,600,000
Loans and Leases Receivable, Collateral for Secured Borrowings	716,800,000	794,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	96,900,000	204,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	154,000,000	185,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	133,300,000	115,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	98,000,000	68,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	58,600,000	59,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	136,700,000	119,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	32,300,000	42,500,000
Loans and Leases Receivable, Allowance	716,800,000	794,900,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	7,000,000
Less loans charged-off	0	200,000	700,000
Agricultural Real Estate Financing Receivable [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	86,200,000	180,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	123,700,000	172,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	126,200,000	109,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	93,500,000	64,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	56,700,000	46,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	124,300,000	105,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	31,800,000	31,400,000
Loans and Leases Receivable, Allowance	649,400,000	710,200,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	7,000,000
Agricultural Real Estate Financing Receivable [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	8,100,000	1,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	20,800,000	12,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,600,000	3,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,600,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	2,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,100,000	11,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	100,000
Loans and Leases Receivable, Allowance	36,600,000	32,300,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Agricultural Real Estate Financing Receivable [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	2,600,000	22,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,500,000	700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,500,000	1,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,900,000	2,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,500,000	10,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	11,300,000	3,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	500,000	11,000,000
Loans and Leases Receivable, Allowance	30,800,000	51,100,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Agricultural Real Estate Financing Receivable [Member] | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		1,300,000
Financing Receivable, Originated in Current Fiscal Year		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		0
Financing Receivable, Originated Two Years before Latest Fiscal Year		1,300,000
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		0
Financing Receivable, Revolving		0
Agricultural Real Estate Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,800,000	1,100,000
Agricultural Real Estate Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	6,100,000
Agricultural Real Estate Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Agricultural Real Estate Financing Receivable [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,800,000	7,200,000
Agricultural Real Estate Financing Receivable [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	709,600,000	780,100,000
Agricultural Real Estate Financing Receivable [Member] | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Real Estate Financing Receivable [Member] | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	61,500,000	37,300,000
Loans and Leases Receivable, Collateral for Secured Borrowings	13,656,800,000	13,456,200,000
Less loans charged-off	18,500,000	21,400,000	4,500,000
Real Estate Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	29,500,000	27,000,000
Real Estate Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	9,600,000	9,600,000
Real Estate Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	2,900,000
Real Estate Financing Receivable [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	39,700,000	39,500,000
Real Estate Financing Receivable [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	13,555,600,000	13,379,400,000
Indirect consumer
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	2,700,000	2,700,000
Loans and Leases Receivable, Collateral for Secured Borrowings	740,900,000	829,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	195,300,000	381,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	265,600,000	177,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	116,000,000	130,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	81,500,000	60,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	33,100,000	33,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	49,400,000	46,700,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Loans and Leases Receivable, Allowance	740,900,000	829,700,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Less loans charged-off	7,300,000	4,000,000	3,500,000
Indirect consumer | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	194,900,000	380,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	264,700,000	176,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	115,400,000	130,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	81,100,000	59,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	32,900,000	33,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	48,800,000	46,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Loans and Leases Receivable, Allowance	737,800,000	826,300,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Indirect consumer | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	400,000	1,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	900,000	900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	600,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	400,000	300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	200,000	200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	600,000	400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Loans and Leases Receivable, Allowance	3,100,000	3,400,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Indirect consumer | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	8,000,000	9,300,000
Indirect consumer | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,200,000	2,400,000
Indirect consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	400,000	600,000
Indirect consumer | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	10,600,000	12,300,000
Indirect consumer | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	727,600,000	814,700,000
Indirect consumer | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	500,000
Indirect consumer | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	3,200,000
Indirect consumer | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	1,800,000
Indirect consumer | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	800,000
Indirect consumer | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	300,000
Indirect consumer | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	700,000
Indirect consumer | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Indirect consumer | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Other consumer
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	300,000	300,000
Loans and Leases Receivable, Collateral for Secured Borrowings	141,600,000	152,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	44,600,000	52,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	33,000,000	32,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,600,000	18,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	9,400,000	8,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	3,600,000	6,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	6,000,000	9,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	26,200,000	25,900,000
Loans and Leases Receivable, Allowance	141,600,000	152,900,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	200,000
Less loans charged-off	4,100,000	3,700,000	2,900,000
Other consumer | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	44,500,000	52,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	32,900,000	31,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,500,000	18,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	9,400,000	8,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	3,600,000	6,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	6,000,000	8,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	26,200,000	25,800,000
Loans and Leases Receivable, Allowance	141,300,000	152,400,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	200,000
Other consumer | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	100,000
Loans and Leases Receivable, Allowance	300,000	500,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Other consumer | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	900,000	800,000
Other consumer | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	200,000	300,000
Other consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	100,000
Other consumer | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,100,000	1,200,000
Other consumer | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	140,200,000	151,400,000
Other consumer | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	200,000
Other consumer | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	500,000
Other consumer | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	200,000
Other consumer | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	400,000
Other consumer | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Other consumer | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	2,600,000
Other consumer | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Other consumer | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	0	0
Loans and Leases Receivable, Collateral for Secured Borrowings	76,500,000	75,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	178,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	76,500,000
Loans and Leases Receivable, Allowance	76,500,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Less loans charged-off	2,600,000	2,400,000	1,800,000
Credit card consumer | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	177,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	75,900,000
Loans and Leases Receivable, Allowance	75,900,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Credit card consumer | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	600,000
Loans and Leases Receivable, Allowance	600,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Credit card consumer | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	700,000	800,000
Credit card consumer | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	500,000	400,000
Credit card consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	600,000	600,000
Credit card consumer | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,800,000	1,800,000
Credit card consumer | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	74,700,000	74,100,000
Credit card consumer | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Credit card consumer | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	2,600,000
Credit card consumer | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Total consumer loans
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	3,000,000	3,000,000
Loans and Leases Receivable, Collateral for Secured Borrowings	959,000,000	1,058,500,000
Less loans charged-off	14,000,000	10,100,000	8,200,000
Total consumer loans | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	9,600,000	10,900,000
Total consumer loans | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,900,000	3,100,000
Total consumer loans | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,000,000	1,300,000
Total consumer loans | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	13,500,000	15,300,000
Total consumer loans | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	942,500,000	1,040,200,000
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	11,500,000	10,200,000
Loans and Leases Receivable, Collateral for Secured Borrowings	2,906,800,000	2,882,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	508,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	533,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	407,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	225,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	111,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	277,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	836,000,000
Loans and Leases Receivable, Allowance	2,906,800,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	8,200,000
Less loans charged-off	3,400,000	8,100,000	3,700,000
Commercial Portfolio Segment [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	481,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	507,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	389,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	215,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	108,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	272,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	762,300,000
Loans and Leases Receivable, Allowance	2,745,700,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	7,600,000
Commercial Portfolio Segment [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	15,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	19,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	9,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	3,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	58,800,000
Loans and Leases Receivable, Allowance	115,200,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	400,000
Commercial Portfolio Segment [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	4,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	6,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	3,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	14,800,000
Loans and Leases Receivable, Allowance	39,500,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	200,000
Commercial Portfolio Segment [Member] | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	3,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	100,000
Loans and Leases Receivable, Allowance	6,400,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	14,500,000	7,100,000
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	1,100,000	1,700,000
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	300,000	2,100,000
Commercial Portfolio Segment [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	15,900,000	10,900,000
Commercial Portfolio Segment [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	2,879,400,000	2,861,500,000
Commercial Portfolio Segment [Member] | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	200,000
Commercial Portfolio Segment [Member] | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	400,000
Commercial Portfolio Segment [Member] | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	500,000
Commercial Portfolio Segment [Member] | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	500,000
Commercial Portfolio Segment [Member] | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	200,000
Commercial Portfolio Segment [Member] | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Commercial Portfolio Segment [Member] | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	1,400,000
Commercial Portfolio Segment [Member] | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	30,400,000	8,700,000
Loans and Leases Receivable, Collateral for Secured Borrowings	769,400,000	708,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	152,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	58,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	34,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	23,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	35,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	9,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	449,400,000
Loans and Leases Receivable, Allowance	769,400,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	6,500,000
Less loans charged-off	0	5,400,000	200,000
Agricultural Financing Receivable [Member] | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	105,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	57,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	31,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	22,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	6,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	7,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	421,900,000
Loans and Leases Receivable, Allowance	656,000,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,400,000
Agricultural Financing Receivable [Member] | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	43,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	28,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	18,500,000
Loans and Leases Receivable, Allowance	97,000,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Agricultural Financing Receivable [Member] | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	2,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	9,000,000
Loans and Leases Receivable, Allowance	16,400,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,100,000
Agricultural Financing Receivable [Member] | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	100,000	800,000
Agricultural Financing Receivable [Member] | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	2,200,000
Agricultural Financing Receivable [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,000,000	100,000
Agricultural Financing Receivable [Member] | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	3,100,000	3,100,000
Agricultural Financing Receivable [Member] | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	735,900,000	696,500,000
Agricultural Financing Receivable [Member] | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Agricultural Financing Receivable [Member] | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Other, including overdrafts
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	0	0
Loans and Leases Receivable, Collateral for Secured Borrowings	100,000	9,200,000
Other, including overdrafts | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	0	0
Other, including overdrafts | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	100,000	9,200,000
Loans held for investment
Loans and Leases Receivable Recorded Investment, Past Due
Non-accrual Loans	106,400,000	59,200,000
Loans and Leases Receivable, Collateral for Secured Borrowings	18,292,100,000	18,114,800,000
Loans held for investment | Financing Receivables, 30 to 59 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	53,700,000	45,800,000
Loans held for investment | Financing Receivables, 60 to 89 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	13,600,000	16,600,000
Loans held for investment | Financing Receivables, Equal to Greater than 90 Days Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	4,900,000	6,400,000
Loans held for investment | Financial Asset, Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	72,200,000	68,800,000
Loans held for investment | Financial Asset, Not Past Due
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Loan in Process	18,113,500,000	17,986,800,000
Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,163,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		882,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		674,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		490,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		261,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		907,600,000
Financing Receivable, Excluding Accrued Interest, Revolving		29,200,000
Loans and Leases Receivable, Allowance		4,408,200,000
Less loans charged-off		3,500,000	0
Non Owner Occupied Loans | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,162,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		861,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		661,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		467,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		241,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		890,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		29,200,000
Loans and Leases Receivable, Allowance		4,313,700,000
Non Owner Occupied Loans | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		13,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		10,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		18,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		19,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		9,800,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		72,400,000
Non Owner Occupied Loans | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		6,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		4,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		7,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		22,100,000
Residential Real Estate 1-4 Family
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		258,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		490,500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		541,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		98,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		32,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		217,500,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		1,639,400,000
Less loans charged-off		200,000	0
Residential Real Estate 1-4 Family | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		258,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		490,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		541,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		98,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		32,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		213,800,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		1,634,600,000
Residential Real Estate 1-4 Family | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		3,700,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		4,800,000
Residential Real Estate
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	45,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	359,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	522,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	501,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	89,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	222,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	471,800,000
Loans and Leases Receivable, Allowance	2,244,300,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	32,100,000
Less loans charged-off	600,000	300,000	100,000
Residential Real Estate | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	44,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	356,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	521,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	500,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	88,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	217,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	471,800,000
Loans and Leases Receivable, Allowance	2,233,000,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	32,100,000
Residential Real Estate | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	5,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Loans and Leases Receivable, Allowance	11,300,000
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Residential Real Estate | Year One, Originated, Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	300,000
Residential Real Estate | Year Two, Originated, Fiscal Year Before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Residential Real Estate | Year Three, Originated, Two Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Residential Real Estate | Year Four, Originated, Three Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Residential Real Estate | Year Five, Originated, Four Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Residential Real Estate | Originated, More than Five Years before Current Fiscal Year
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	100,000
Residential Real Estate | Revolving
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	0
Residential Real Estate | Revolving, Converted to Term
Loans and Leases Receivable Recorded Investment, Past Due
Less loans charged-off	$ 0
Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		812,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		737,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		548,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		281,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		179,900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		574,000,000
Financing Receivable, Excluding Accrued Interest, Revolving		19,800,000
Loans and Leases Receivable, Allowance		3,153,500,000
Less loans charged-off		2,500,000	2,300,000
Commercial Real Estate Owner Occupied | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		793,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		718,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		533,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		266,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		165,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		551,300,000
Financing Receivable, Excluding Accrued Interest, Revolving		18,200,000
Loans and Leases Receivable, Allowance		3,047,200,000
Commercial Real Estate Owner Occupied | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		8,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		3,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		8,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		8,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		17,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		500,000
Loans and Leases Receivable, Allowance		48,800,000
Commercial Real Estate Owner Occupied | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		10,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		14,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		12,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		6,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		5,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		5,500,000
Financing Receivable, Excluding Accrued Interest, Revolving		1,100,000
Loans and Leases Receivable, Allowance		55,700,000
Commercial Real Estate Owner Occupied | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		1,800,000
Financing Receivable, Originated in Current Fiscal Year		400,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		1,400,000
Financing Receivable, Originated Two Years before Latest Fiscal Year		0
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		0
Financing Receivable, Revolving		0
Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		369,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		204,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		189,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		52,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		35,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		115,700,000
Financing Receivable, Excluding Accrued Interest, Revolving		1,000,000
Loans and Leases Receivable, Allowance		966,900,000
Less loans charged-off		5,700,000	0
Commercial Real Estate Multifamily | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		369,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		204,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		189,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		52,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		35,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		113,700,000
Financing Receivable, Excluding Accrued Interest, Revolving		1,000,000
Loans and Leases Receivable, Allowance		964,900,000
Commercial Real Estate Multifamily | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		300,000
Financing Receivable, Originated in Current Fiscal Year		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		0
Financing Receivable, Originated Two Years before Latest Fiscal Year		0
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		300,000
Financing Receivable, Revolving		0
Commercial Real Estate Multifamily | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		1,700,000
Financing Receivable, Originated in Current Fiscal Year		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		0
Financing Receivable, Originated Two Years before Latest Fiscal Year		0
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		1,700,000
Financing Receivable, Revolving		0
Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		527,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		370,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		219,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		132,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		124,400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		178,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		697,400,000
Loans and Leases Receivable, Allowance		2,249,400,000
Less loans charged-off		6,600,000	$ 3,000,000
Commercial and Floor Plans | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		501,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		358,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		214,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		124,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		120,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		171,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		631,600,000
Loans and Leases Receivable, Allowance		2,122,300,000
Commercial and Floor Plans | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		9,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		3,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		3,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		3,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		3,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		2,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		47,200,000
Loans and Leases Receivable, Allowance		72,700,000
Commercial and Floor Plans | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		15,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		6,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		4,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		4,900,000
Financing Receivable, Excluding Accrued Interest, Revolving		18,500,000
Loans and Leases Receivable, Allowance		52,700,000
Commercial and Floor Plans | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Loans and Leases Receivable, Allowance		1,700,000
Financing Receivable, Originated in Current Fiscal Year		300,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year		1,300,000
Financing Receivable, Originated Two Years before Latest Fiscal Year		0
Financing Receivable, Originated Three Years before Latest Fiscal Year		0
Financing Receivable, Originated Four Years before Latest Fiscal Year		0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year		0
Financing Receivable, Revolving		100,000
Agriculture
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		176,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		67,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		35,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		12,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		10,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		3,300,000
Financing Receivable, Excluding Accrued Interest, Revolving		402,100,000
Loans and Leases Receivable, Allowance		706,400,000
Agriculture | Pass
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		127,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		59,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		31,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		10,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		8,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		3,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		375,100,000
Loans and Leases Receivable, Allowance		616,100,000
Agriculture | Substandard
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		22,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		4,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		1,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Revolving		800,000
Loans and Leases Receivable, Allowance		33,000,000
Agriculture | Other Assets Especial Mentioned
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		26,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		2,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		1,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		26,200,000
Loans and Leases Receivable, Allowance		56,800,000
Agriculture | Doubtful
Loans and Leases Receivable Recorded Investment, Past Due
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		0
Loans and Leases Receivable, Allowance		$ 500,000

Loans - Schedule of Recorded In

Loans - Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		$ 4,408,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,163,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		882,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		674,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		490,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		261,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		907,600,000
Financing Receivable, Excluding Accrued Interest, Revolving		29,200,000
Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		3,153,500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		812,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		737,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		548,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		281,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		179,900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		574,000,000
Financing Receivable, Excluding Accrued Interest, Revolving		19,800,000
Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		966,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		369,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		204,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		189,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		52,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		35,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		115,700,000
Financing Receivable, Excluding Accrued Interest, Revolving		1,000,000
Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		386,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		159,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		117,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		29,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		17,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		11,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		29,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		22,200,000
Residential Real Estate
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	$ 2,244,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	45,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	359,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	522,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	501,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	89,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	222,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	471,800,000
Residential Real Estate | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	2,233,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	44,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	356,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	521,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	500,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	88,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	217,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	471,800,000
Residential Real Estate | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	11,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	5,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		516,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		118,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		120,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		6,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		270,100,000
Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,042,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		461,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		399,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		112,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		45,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		21,900,000
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	716,800,000	794,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	96,900,000	204,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	154,000,000	185,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	133,300,000	115,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	98,000,000	68,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	58,600,000	59,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	136,700,000	119,600,000
Financing Receivable, Excluding Accrued Interest, Revolving	32,300,000	42,500,000
Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		2,249,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		527,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		370,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		219,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		132,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		124,400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		178,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		697,400,000
Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		532,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		192,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		136,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		72,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		30,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		32,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		40,900,000
Financing Receivable, Excluding Accrued Interest, Revolving		28,900,000
Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		706,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		176,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		67,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		35,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		12,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		10,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		3,300,000
Financing Receivable, Excluding Accrued Interest, Revolving		402,100,000
Residential Real Estate 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,639,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		258,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		490,500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		541,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		98,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		32,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		217,500,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Residential Real Estate 1-4 Family | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,634,600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		258,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		490,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		541,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		98,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		32,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		213,800,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Residential Real Estate 1-4 Family | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		4,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		3,700,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Home Equity Loan
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		548,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		24,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		8,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		5,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		5,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		5,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		16,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		483,000,000
Home Equity Loan | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		546,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		23,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		8,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		5,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		5,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		5,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		15,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		482,800,000
Home Equity Loan | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		2,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		1,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		200,000
Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	740,900,000	829,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	195,300,000	381,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	265,600,000	177,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	116,000,000	130,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	81,500,000	60,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	33,100,000	33,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	49,400,000	46,700,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Indirect consumer | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	737,800,000	826,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	194,900,000	380,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	264,700,000	176,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	115,400,000	130,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	81,100,000	59,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	32,900,000	33,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	48,800,000	46,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Indirect consumer | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	3,100,000	3,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	400,000	1,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	900,000	900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	600,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	400,000	300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	200,000	200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	600,000	400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	141,600,000	152,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	44,600,000	52,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	33,000,000	32,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,600,000	18,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	9,400,000	8,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	3,600,000	6,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	6,000,000	9,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	26,200,000	25,900,000
Other consumer | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	141,300,000	152,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	44,500,000	52,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	32,900,000	31,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,500,000	18,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	9,400,000	8,500,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	3,600,000	6,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	6,000,000	8,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	26,200,000	25,800,000
Other consumer | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	300,000	500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	100,000	100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	100,000
Credit card consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	76,500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	178,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	76,500,000
Credit card consumer | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		75,900,000
Credit card consumer | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		100,300,000
Credit card consumer | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,900,000
Credit card consumer | Performing Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	75,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	177,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	75,900,000
Credit card consumer | Performing Financial Instruments | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		75,400,000
Credit card consumer | Performing Financial Instruments | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		100,000,000
Credit card consumer | Performing Financial Instruments | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,900,000
Credit card consumer | Nonperforming Financial Instruments
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	600,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	600,000
Credit card consumer | Nonperforming Financial Instruments | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		500,000
Credit card consumer | Nonperforming Financial Instruments | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		300,000
Credit card consumer | Nonperforming Financial Instruments | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	2,906,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	508,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	533,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	407,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	225,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	111,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	277,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	836,000,000
Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	769,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	152,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	58,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	34,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	23,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	35,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	9,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	449,400,000
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	8,869,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,337,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,085,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,675,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,215,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	774,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,706,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	47,000,000
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,826,500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	501,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	758,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	356,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	36,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	16,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	36,800,000
Financing Receivable, Excluding Accrued Interest, Revolving	104,400,000
Pass | Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		4,313,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,162,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		861,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		661,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		467,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		241,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		890,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		29,200,000
Pass | Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		3,047,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		793,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		718,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		533,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		266,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		165,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		551,300,000
Financing Receivable, Excluding Accrued Interest, Revolving		18,200,000
Pass | Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		964,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		369,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		204,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		189,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		52,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		35,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		113,700,000
Financing Receivable, Excluding Accrued Interest, Revolving		1,000,000
Pass | Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		374,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		152,500,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		114,400,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		29,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		17,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		10,900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		28,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		22,200,000
Pass | Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		515,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		118,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		119,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		5,800,000
Financing Receivable, Excluding Accrued Interest, Revolving		270,100,000
Pass | Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		964,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		442,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		374,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		89,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		45,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		10,600,000
Pass | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	649,400,000	710,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	86,200,000	180,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	123,700,000	172,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	126,200,000	109,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	93,500,000	64,800,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	56,700,000	46,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	124,300,000	105,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	31,800,000	31,400,000
Pass | Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		2,122,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		501,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		358,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		214,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		124,300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		120,300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		171,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		631,600,000
Pass | Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		524,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		191,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		134,500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		69,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		30,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		29,900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		39,500,000
Financing Receivable, Excluding Accrued Interest, Revolving		28,900,000
Pass | Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		616,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		127,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		59,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		31,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		10,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		8,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		3,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		375,100,000
Pass | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	2,745,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	481,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	507,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	389,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	215,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	108,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	272,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	762,300,000
Pass | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	656,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	105,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	57,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	31,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	22,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	6,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	7,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	421,900,000
Pass | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	8,596,900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,268,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,065,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,612,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,200,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	716,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,660,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	46,500,000
Pass | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,768,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	493,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	735,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	331,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	36,700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	16,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	36,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	104,400,000
Other Assets Especial Mentioned | Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		22,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		1,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		6,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		4,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		7,400,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Other Assets Especial Mentioned | Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		55,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		10,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		14,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		12,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		6,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		5,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		5,500,000
Financing Receivable, Excluding Accrued Interest, Revolving		1,100,000
Other Assets Especial Mentioned | Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,700,000
Other Assets Especial Mentioned | Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		7,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		6,700,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Other Assets Especial Mentioned | Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		36,700,000
Other Assets Especial Mentioned | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	30,800,000	51,100,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	2,600,000	22,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,500,000	700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,500,000	1,200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,900,000	2,600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,500,000	10,000,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	11,300,000	3,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	500,000	11,000,000
Other Assets Especial Mentioned | Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		52,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		15,900,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		6,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		4,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		4,900,000
Financing Receivable, Excluding Accrued Interest, Revolving		18,500,000
Other Assets Especial Mentioned | Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		5,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		1,200,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		1,400,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Other Assets Especial Mentioned | Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		56,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		26,100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		2,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		1,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		26,200,000
Other Assets Especial Mentioned | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	39,500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	4,700,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	6,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	3,100,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,900,000
Financing Receivable, Excluding Accrued Interest, Revolving	14,800,000
Other Assets Especial Mentioned | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	16,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	2,600,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	9,000,000
Other Assets Especial Mentioned | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	113,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	4,200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,100,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	42,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	12,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	27,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	17,100,000
Financing Receivable, Excluding Accrued Interest, Revolving	300,000
Other Assets Especial Mentioned | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	9,500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	500,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	200,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Substandard | Non Owner Occupied Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		72,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		13,900,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		10,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		18,200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		19,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		9,800,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Substandard | Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		48,800,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		8,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		3,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		8,900,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		8,500,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		17,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		500,000
Substandard | Commercial Real Estate Multifamily
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		300,000
Substandard | Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Substandard | Residential Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		900,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		400,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Substandard | Commercial Real Estate Construction [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		41,200,000
Substandard | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	36,600,000	32,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	8,100,000	1,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	20,800,000	12,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,600,000	3,500,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,600,000	600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	400,000	2,700,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,100,000	11,300,000
Financing Receivable, Excluding Accrued Interest, Revolving	0	100,000
Substandard | Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		72,700,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		9,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		3,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		3,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		3,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		3,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		2,100,000
Financing Receivable, Excluding Accrued Interest, Revolving		47,200,000
Substandard | Commercial Purpose Secured by 1-4 Family
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		3,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		100,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		300,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		900,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		1,200,000
Financing Receivable, Excluding Accrued Interest, Revolving		0
Substandard | Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		33,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		22,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		4,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		2,800,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		600,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		1,200,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		200,000
Financing Receivable, Excluding Accrued Interest, Revolving		800,000
Substandard | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	115,200,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	15,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	19,600,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	9,000,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,600,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	3,000,000
Financing Receivable, Excluding Accrued Interest, Revolving	58,800,000
Substandard | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	97,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	43,800,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,700,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	700,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	28,800,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,200,000
Financing Receivable, Excluding Accrued Interest, Revolving	18,500,000
Substandard | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	157,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	65,400,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	11,800,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	18,900,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,400,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	30,100,000
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	28,500,000
Financing Receivable, Excluding Accrued Interest, Revolving	200,000
Substandard | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	36,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,000,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	4,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	24,400,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	200,000
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	400,000
Financing Receivable, Excluding Accrued Interest, Revolving	0
Doubtful | Commercial Real Estate Owner Occupied
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,800,000
Doubtful | Land Acquisition And Development Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		3,200,000
Doubtful | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,300,000
Doubtful | Commercial and Floor Plans
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		1,700,000
Doubtful | Agriculture
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance		500,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year		500,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year		0
Financing Receivable, Excluding Accrued Interest, Revolving		$ 0
Doubtful | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	6,400,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	3,300,000
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,600,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	100,000
Financing Receivable, Excluding Accrued Interest, Revolving	100,000
Doubtful | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	1,300,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,300,000
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Doubtful | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans
Loans and Leases Receivable, Allowance	13,000,000
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	13,000,000
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	$ 0

Loans Held for Investment - S_4

Loans Held for Investment - Schedule of PCD Loans (Details) $ in Millions	Feb. 01, 2022 USD ($)
Receivables [Abstract]
Purchase Price (Initial Fair Value)	$ 623.3
Allowance for Credit Losses	(298.2)
Non-Credit Discount at Acquisition	57.7
Par Value (Unpaid Principal Balance)	979.2
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses, Decreases	238.7
Business Combination, Impact on Purchased Credit Deteriorated Loans	59.5
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Difference Between Amortized Cost Basis and Unpaid Principal Balance	39.6
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Interest Applied to Principal	$ 18.1

Loans - Schedule of Recorded _2

Loans - Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Financing Receivable, Accrued Interest, Writeoff	$ (2.7)	$ 1.5
Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	8,869.2	8,528.6
Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1,826.5	1,944.4
Residential Mortgage [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	2,244.3	2,188.3
Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	716.8	794.9
Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	13,656.8	13,456.2
Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	769.4	708.3
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	2,906.8	2,882.6
Loans held for investment
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	18,292.1	18,114.8
Indirect consumer
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	740.9	829.7
Other consumer
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	141.6	152.9
Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	52.6	39.1
Collateral | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	26.6	17.5
Collateral | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	17	3.2
Collateral | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1.2	6
Collateral | Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	45.3	27.2
Collateral | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0.7	7.3
Collateral | Residential Real Estate
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0.5	0.5
Collateral | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	6.6	4.6
Business Assets Pledged as Collateral | Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	5.2	7.1
Business Assets Pledged as Collateral | Collateral | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	1.7
Business Assets Pledged as Collateral | Collateral | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Business Assets Pledged as Collateral | Collateral | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0.2
Business Assets Pledged as Collateral | Collateral | Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	1.9
Business Assets Pledged as Collateral | Collateral | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0.7	2.1
Business Assets Pledged as Collateral | Collateral | Residential Real Estate
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Business Assets Pledged as Collateral | Collateral | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	4.5	3.1
Real Property Pledged as Collateral | Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	46.7	32
Real Property Pledged as Collateral | Collateral | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	26.6	15.8
Real Property Pledged as Collateral | Collateral | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	17	3.2
Real Property Pledged as Collateral | Collateral | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1.2	5.8
Real Property Pledged as Collateral | Collateral | Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	45.3	25.3
Real Property Pledged as Collateral | Collateral | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	5.2
Real Property Pledged as Collateral | Collateral | Residential Real Estate
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0.5	0.5
Real Property Pledged as Collateral | Collateral | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	1.4	1.5
Other Property | Collateral
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0.7	0
Other Property | Collateral | Commercial Real Estate Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property | Collateral | Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property | Collateral | Agricultural Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property | Collateral | Real Estate Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property | Collateral | Agricultural Financing Receivable [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property | Collateral | Residential Real Estate
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	0	0
Other Property | Collateral | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Recorded Investment, Impaired [Line Items]
Loans and Leases Receivable, Collateral for Secured Borrowings	$ 0.7	$ 0

Loans Held for Investment - Nar

Loans Held for Investment - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Receivables [Abstract]
Accrued interest receivable	$ 129.1	$ 118.3
Financing Receivable, Loan in Process	$ 6.7

Loans Held for Investment - S_5

Loans Held for Investment - Schedule of Modifications to Borrowers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Loans and Leases Receivable, Troubled Debt Restructuring
Accrued interest receivable	$ 129.1	$ 118.3
Financing Receivable, Modified in Period, Accrued Interest, Amount	1.6
Commercial Real Estate Portfolio Segment [Member]
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 31.8
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.36%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 31.8
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.36%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0.35%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	5 years 9 months 18 days
Commercial Real Estate Portfolio Segment [Member] | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 28.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	28.6
Commercial Real Estate Portfolio Segment [Member] | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.6
Commercial Real Estate Portfolio Segment [Member] | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.1
Commercial Real Estate Portfolio Segment [Member] | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.5
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 1.5
Commercial Real Estate Portfolio Segment [Member] | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	6 years
Commercial Real Estate Portfolio Segment [Member] | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 1.3
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 1.3
Commercial Real Estate Portfolio Segment [Member] | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0.25%
Real Estate Construction Financing Receivable [Member]
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 13.7
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.75%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 13.7
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.75%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	9 years 1 month 6 days
Real Estate Construction Financing Receivable [Member] | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 13.7
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	13.7
Real Estate Construction Financing Receivable [Member] | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Real Estate Construction Financing Receivable [Member] | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Real Estate Construction Financing Receivable [Member] | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Real Estate Construction Financing Receivable [Member] | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	0 years
Real Estate Construction Financing Receivable [Member] | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Real Estate Construction Financing Receivable [Member] | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0%
Residential Real Estate
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.7
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.03%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.7
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.03%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	131 years 7 months 6 days
Residential Real Estate | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.6
Residential Real Estate | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Residential Real Estate | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Residential Real Estate | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Residential Real Estate | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	0 years
Residential Real Estate | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.3
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.3
Residential Real Estate | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0%
Agricultural Real Estate Financing Receivable [Member]
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 6.4
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.89%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 6.4
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.89%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	4 years 6 months
Agricultural Real Estate Financing Receivable [Member] | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 6.4
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	6.4
Agricultural Real Estate Financing Receivable [Member] | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Agricultural Real Estate Financing Receivable [Member] | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Agricultural Real Estate Financing Receivable [Member] | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Agricultural Real Estate Financing Receivable [Member] | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	0 years
Agricultural Real Estate Financing Receivable [Member] | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Agricultural Real Estate Financing Receivable [Member] | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0%
Real Estate Financing Receivable [Member]
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 52.6
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.39%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 52.6
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.39%
Real Estate Financing Receivable [Member] | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 49.3
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	49.3
Real Estate Financing Receivable [Member] | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.6
Real Estate Financing Receivable [Member] | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.1
Real Estate Financing Receivable [Member] | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Real Estate Financing Receivable [Member] | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Indirect consumer
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.01%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.01%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	8 years 3 months 18 days
Indirect consumer | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.1
Indirect consumer | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Indirect consumer | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Indirect consumer | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Indirect consumer | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	0 years
Indirect consumer | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Indirect consumer | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0%
Other consumer
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.07%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.07%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	62 years 1 month 6 days
Other consumer | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.1
Other consumer | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Other consumer | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Other consumer | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Other consumer | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	0 years
Other consumer | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Other consumer | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0%
Total consumer loans
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.2
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.02%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.2
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.02%
Total consumer loans | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0.2
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.2
Total consumer loans | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Total consumer loans | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Total consumer loans | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Total consumer loans | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Commercial Portfolio Segment [Member]
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 7.6
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.26%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 7.6
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.26%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	12 years 2 months 12 days
Commercial Portfolio Segment [Member] | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 7.4
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	7.4
Commercial Portfolio Segment [Member] | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.2
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.2
Commercial Portfolio Segment [Member] | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Commercial Portfolio Segment [Member] | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Commercial Portfolio Segment [Member] | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	14 years 7 months 6 days
Commercial Portfolio Segment [Member] | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Commercial Portfolio Segment [Member] | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0.51%
Agricultural Financing Receivable [Member]
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 36.1
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	4.69%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 36.1
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	4.69%
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0%
Financing Receivable, Modified, Weighted Average Term Increase from Modification	9 years 2 months 12 days
Agricultural Financing Receivable [Member] | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 36.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	36.1
Agricultural Financing Receivable [Member] | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Agricultural Financing Receivable [Member] | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Agricultural Financing Receivable [Member] | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Agricultural Financing Receivable [Member] | Weighted-Average Months of Term Extension
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction	0 years
Agricultural Financing Receivable [Member] | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0
Agricultural Financing Receivable [Member] | Weighted-Average Interest Rate Reduction
Loans and Leases Receivable, Troubled Debt Restructuring
Combination Term Extension and Interest Rate Reduction Percent	0%
Loans held for investment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 96.5
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.53%
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 96.5
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage	0.53%
Loans held for investment | Extension of terms or maturity
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 93
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	93
Loans held for investment | Extended Maturity and Interest Rate Reduction
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.8
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0.8
Loans held for investment | Interest rate adjustment
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.1
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.1
Loans held for investment | Principal Forgiveness
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Loans held for investment | Principal Forgiven
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	1.6
Loans and Leases Receivable, Troubled Debt Restructuring
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 1.6

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment
Depreciation	$ 34.3	$ 35.1	$ 28
Premises and equipment, gross	673.5	666.9
Less accumulated depreciation	(229.2)	(222.2)
Premises and equipment, net	444.3	444.7
Land
Property, Plant and Equipment
Premises and equipment, gross	87.7	86.7
Buildings and improvements
Property, Plant and Equipment
Premises and equipment, gross	474.2	469.2
Furniture and equipment
Property, Plant and Equipment
Premises and equipment, gross	$ 111.6	$ 111

Company-Owned Life Insurance (D

Company-Owned Life Insurance (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Company - Owned Life Insurance, By Type
Total	$ 502.4	$ 497.9
Key executive, principal shareholder
Schedule of Company - Owned Life Insurance, By Type
Cash surrender value of life insurance	1.8	3.2
Key executive split dollar
Schedule of Company - Owned Life Insurance, By Type
Cash surrender value of life insurance	5	7.1
FIB | Group life
Schedule of Company - Owned Life Insurance, By Type
Cash surrender value of life insurance	$ 495.6	$ 487.6

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Repossessed Assets [Abstract]
Real Estate Acquired Through Foreclosure, Valuation Adjustments	$ 1.1	$ 2.8	$ 0
Real Estate Acquired Through Foreclosure [Roll Forward]
Balance at beginning of year	12.7	2	2.5
Acquired through acquisitions	0	15.8	0
Additions	8.3	0.4	0.9
Dispositions	(3.4)	(2.7)	(1.4)
Balance at end of year	16.5	$ 12.7	$ 2
Mortgage Loans in Process of Foreclosure, Amount	0.5
Carrying value of foreclosed OREO	$ 0

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities - Notional Amounts and Estimated Fair Values of Derivatives (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Derivative Asset, Notional Amount	$ 2,144.7	$ 2,290.7
Derivative Assets, Estimated Fair Value	37.4	45.2
Derivative Liability, Notional Amount	2,295.7	2,449
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Derivative Instruments and Hedges, Assets	193.3	191.9
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	6.7	8.1
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Assets, Estimated Fair Value	37.3	45.1
Derivative Liabilities, Estimated Fair Value	127.1	159.6
Derivative Instruments and Hedges, Assets	850
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivative Assets, Estimated Fair Value	0.1
Forward Contracts [Member]
Derivative [Line Items]
Derivative Assets, Estimated Fair Value		0.1
Derivative Liabilities, Estimated Fair Value	0.1
Not Designated as Hedging Instrument | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	1,589	1,728.1
Derivative Assets, Estimated Fair Value	34.3	41.6
Derivative Liability, Notional Amount	1,589	1,728.1
Derivative Liabilities, Estimated Fair Value	121.1	153.9
Not Designated as Hedging Instrument | Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	5.7	0
Derivative Assets, Estimated Fair Value	0.1	0
Derivative Liability, Notional Amount	0	14.8
Derivative Liabilities, Estimated Fair Value	0	0
Not Designated as Hedging Instrument | Forward Contracts [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	0	12.6
Derivative Liability, Notional Amount	5.6	0
Derivative Liabilities, Estimated Fair Value	0.1	0
Designated as Hedging Instrument | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount	550	550
Derivative Assets, Estimated Fair Value	3	3.5
Derivative Liability, Notional Amount	300	300
Derivative Liabilities, Estimated Fair Value	$ 2.4	$ 0.3

Derivatives and Hedging Activ_3

Derivatives and Hedging Activities - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2022
Derivative [Line Items]
Derivative liability, notional amount	$ 2,295,700,000	$ 2,449,000,000
Derivative, Collateral, Right to Reclaim Securities	0	0
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	9,100,000
Derivative Instruments and Hedges, Assets	193,300,000	191,900,000
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	6,700,000	8,100,000
Derivative Instruments and Hedges, Noncurrent	900,000,000
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	6,500,000	2,200,000
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(7,500,000)
Interest Income, Hedge Basis Adjustment, Portfolio Layer Method, Increase (Decrease)	1,400,000
Three-Year Forward Starting, Four-Year Pay Fixed Interest Rate Swap
Derivative [Line Items]
Derivative Instruments and Hedges, Assets			$ 200,000,000
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)			$ 8,500,000
Two-Year Forward Starting, Three-year Pay Fixed Interest Rate Swap
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	500,000,000
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	23,300,000
Interest Rate Collars
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	300,000,000
Interest Rate Swap
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Securities	0	$ 0
Derivative Instruments and Hedges, Assets	850,000,000
Interest Rate Swap and Interest Rate Collar
Derivative [Line Items]
Derivative Instruments and Hedges, Assets	1,150,000,000
Collateral Pledged
Derivative [Line Items]
Derivative, Fair Value, Net	0
Derivative, Collateral, Right to Reclaim Securities	$ 0

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities - Schedule of Master Netting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	$ 37.4	$ 45.2
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	32.7	45.1
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	4.7	0.1
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	127.3	159.6
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	127.3	159.6
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral [Abstract]
Securities Sold under Agreements to Repurchase, Gross	782.7	1,052.9
Securities Sold under Agreements to Repurchase, Asset	0	0
Securities Sold under Agreements to Repurchase, Total	782.7	1,052.9
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	782.7	1,052.9
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral, Total	0	0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross	910	1,212.5
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Asset	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Total	910	1,212.5
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Cash	782.7	1,052.9
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral, Total	127.3	159.6
Derivative Asset, Notional Amount	2,144.7	2,290.7
Derivative Assets, Estimated Fair Value	37.4	45.2
Derivative Liability, Notional Amount	2,295.7	2,449
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Collateral Pledged
Offsetting Derivative Liabilities [Abstract]
Derivative, Collateral, Right to Reclaim Securities	0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative, Fair Value, Net	0
Interest Rate Swap [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	37.3	45.1
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	32.7	45.1
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	4.6	0
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	127.1	159.6
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	127.1	159.6
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Assets, Estimated Fair Value	37.3	45.1
Derivative Liabilities, Estimated Fair Value	127.1	159.6
Interest Rate Swap [Member] | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	1,589	1,728.1
Derivative Assets, Estimated Fair Value	34.3	41.6
Derivative Liability, Notional Amount	1,589	1,728.1
Derivative Liabilities, Estimated Fair Value	121.1	153.9
Interest Rate Swap [Member] | Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	550	550
Derivative Assets, Estimated Fair Value	3	3.5
Derivative Liability, Notional Amount	300	300
Derivative Liabilities, Estimated Fair Value	2.4	0.3
Forward Contracts [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset		0.1
Derivative Asset, Fair Value, Gross Liability		0
Derivative, Collateral, Obligation to Return Securities		0
Derivative, Collateral, Obligation to Return Cash		0
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total		0.1
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.1
Derivative Liability, Fair Value, Gross Asset	0
Derivative, Collateral, Right to Reclaim Securities	0
Derivative, Collateral, Right to Reclaim Cash	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	0.1
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Assets, Estimated Fair Value		0.1
Derivative Liabilities, Estimated Fair Value	0.1
Forward Contracts [Member] | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	0	12.6
Derivative Liability, Notional Amount	5.6	0
Derivative Liabilities, Estimated Fair Value	0.1	0
Derivative, Fair Value, Net	0	0.1
Interest Rate Collars | Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Notional Amount	300	300
Derivative Liabilities, Estimated Fair Value	3.6	5.4
Risk Participation Agreements
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.1
Derivative Liability, Fair Value, Gross Asset	0
Derivative, Collateral, Right to Reclaim Securities	0
Derivative, Collateral, Right to Reclaim Cash	0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	0.1
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liabilities, Estimated Fair Value	0.1
Risk Participation Agreements | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Notional Amount	101.1	106.1
Derivative Liabilities, Estimated Fair Value	0.1	0
Interest Rate Lock Commitments [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	0.1
Derivative Asset, Fair Value, Gross Liability	0
Derivative, Collateral, Obligation to Return Securities	0
Derivative, Collateral, Obligation to Return Cash	0
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	0.1
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Assets, Estimated Fair Value	0.1
Interest Rate Lock Commitments [Member] | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	5.7	0
Derivative Assets, Estimated Fair Value	0.1	0
Derivative Liability, Notional Amount	0	14.8
Derivative Liabilities, Estimated Fair Value	$ 0	$ 0

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities - Pre-tax Gains and Losses on Derivative Contracts (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Fee Income on Derivatives	$ 0.7	$ 5.9
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ (0.1)	$ (1.7)

Mortgage Servicing Rights - Sch

Mortgage Servicing Rights - Schedule of Mortgage Servicing Rights (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Servicing Asset at Amortized Value, Balance [Roll Forward]
Balance at end of year, net of valuation reserve	$ 28.3	$ 31.1
Mortgage loans
Servicing Asset at Amortized Value, Balance [Roll Forward]
Servicing asset at amortized cost, before valuation reserve, beginning	31.1	31.6	$ 34.3
Originations of mortgage servicing rights	1.1	2.5	3.7
Amortization expense	(3.9)	(4.3)	(6.4)
Servicing asset at amortized cost, before valuation reserve, ending	28.3	31.1	31.6
Acquisition of mortgage servicing rights	0	1.3	0
Less valuation reserve	0	0	(3.4)
Balance at end of year, net of valuation reserve	28.3	31.1	28.2
Principal balance of serviced loans underlying mortgage servicing rights	$ 3,091.1	$ 3,259.8	$ 3,203.7
Mortgage servicing rights as a percentage of serviced loans	0.0092	0.0095	0.0088

Mortgage Servicing Rights - Nar

Mortgage Servicing Rights - Narrative (Details) - Mortgage loans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Mortgage servicing rights, fair value	$ 38.8	$ 37.4
Servicing asset at fair value, assumptions used to estimate fair value, weighted average life	7 years 9 months 18 days	7 years 7 months 6 days
Impairment reversals	$ 0	$ (3.4)	$ (6.9)
Permanent impairment charged against carrying value	$ 0
Minimum
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Servicing assets at fair value, assumptions used to estimate fair value, discount rate	11.90%	11.80%
Servicing assets at fair value, assumptions used to estimate fair value, prepayment speed	0.40%	0.50%
Maximum [Member]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Servicing assets at fair value, assumptions used to estimate fair value, discount rate	12.80%	13.50%
Servicing assets at fair value, assumptions used to estimate fair value, prepayment speed	1.60%	3.40%

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deposits, by Type [Abstract]
Non-interest bearing demand	$ 6,029,600	$ 7,560,000
Interest bearing:
Demand	6,507,800	7,205,900
Savings	7,775,800	8,379,300
Total	811,600	438,000
Time, other	2,198,300	1,490,400
Total interest bearing	17,293,500	17,513,600
Total deposits	23,323,100	25,073,600
Brokered time deposits	0
Time deposits obtained through Certificate of Deposit Account Registry Service (CDARS)	26,600	36,600
Time deposits of $250,000 or more	811,600	438,000
FDIC deposit insurance limit	250,000
Time, $250 and Over
Due within 3 months or less	219,700
Due after 3 months and within 6 months	233,900
Due after 6 months and within 12 months	279,500
Due within 2025	62,800
Due within 2026	9,100
Due within 2027	4,900
Due within 2028 and thereafter	1,700
Total	811,600	438,000
Total Time
Due within 3 months or less	770,400
Due after 3 months and within 6 months	854,000
Due after 6 months and within 12 months	1,024,300
Due within 2025	277,100
Due within 2026	48,200
Due within 2027	28,400
Due within 2028 and thereafter	7,500
Total	3,009,900
Interest expense, time deposits, $100,000 or more	$ 21,500	$ 2,500	$ 900

Long-Term Debt and Other Borr_3

Long-Term Debt and Other Borrowed Funds (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	May 31, 2020
Debt Instrument
Stated interest rate			5.25%
Long-term debt	$ 99	$ 98.9
Long-term debt and capital lease obligations	120.8	120.8
Fiscal Year Maturities of Long-term Debt
2018	0.1
2019	0.1
2020	0.1
2021	0.2
2022	0.2
Thereafter	120.1
Long-term debt and capital lease obligations	120.8	120.8
Advances from FHLB	2,603	2,327
Other borrowings	2,603	2,327
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	1
Other Borrowings	0
Federal Home Loan Bank Advances	$ 0
FIB
Fiscal Year Maturities of Long-term Debt
Ownership percentage in subsidiary	99.90%
Parent
Debt Instrument
Long-term debt	$ 99	$ 98.9
4.48% fixed rate borrowings in tenors up to one-month
Debt Instrument
Stated interest rate		4.48%
Fiscal Year Maturities of Long-term Debt
Advances from FHLB		$ 1,500
Average fixed rate borrowings in tenors of 3-months
Debt Instrument
Stated interest rate	5.52%
Fiscal Year Maturities of Long-term Debt
Advances from FHLB	$ 2,603
Variable rate overnight borrowings
Debt Instrument
Stated interest rate		4.60%
Fiscal Year Maturities of Long-term Debt
Advances from FHLB		$ 827
Capital lease obligations | Capital Lease Obligation, 8.00% | Subsidiaries
Debt Instrument
Stated interest rate	8%
Finance Lease, Liability	$ 0.9	1
Notes payable | Subsidiaries
Fiscal Year Maturities of Long-term Debt
Long Term Debt, Acquired or Assumed	20.9	20.9
Notes payable | Note Payable, 1.30%, maturing March 31, 2038 [Member] | Subsidiaries
Debt Instrument
Long-term debt	2	2
Notes payable | Note Payable, 1.30%, Maturing June 1, 2034 [Member] | Subsidiaries
Debt Instrument
Long-term debt	$ 0.6	0.6
Notes payable | Note Payable, One Percent | Subsidiaries
Debt Instrument
Stated interest rate	1%
Notes payable | Note Payable, 1.00% | Subsidiaries
Debt Instrument
Long-term debt	$ 5.1	5.1
Notes payable | Note Payable, One Point Three Percent | Subsidiaries
Debt Instrument
Stated interest rate	1.30%
Notes payable | Note Payable, One Point Three Zero Percent | Subsidiaries
Debt Instrument
Stated interest rate	1.30%
Notes payable | Note Payable, Three Point Two Five Percent | Subsidiaries
Debt Instrument
Stated interest rate	3.25%
Notes payable | Note Payable, 1.12%, Maturing December 31, 2045 | Subsidiaries
Debt Instrument
Long-term debt	$ 6.8	6.8
Notes payable | Note Payable, 1.35%, Maturing December 31, 2046 | Subsidiaries
Debt Instrument
Long-term debt	$ 6.4	$ 6.4
Notes payable | Note Payable, One Point One Two Percent | Subsidiaries
Debt Instrument
Stated interest rate	1.12%
Notes payable | Note Payable, One Point Three Five Percent | Subsidiaries
Debt Instrument
Stated interest rate	1.35%
Federal Home Loan Bank | Notes Payable to FHLB | Subsidiaries
Fiscal Year Maturities of Long-term Debt
FHLB, advances, maximum amount available	$ 6,222.6
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds	3,619.6
Secured Debt
Fiscal Year Maturities of Long-term Debt
Line of credit facility, maximum borrowing capacity	3,039.5
Federal Funds Purchased
Fiscal Year Maturities of Long-term Debt
Line of credit facility, maximum borrowing capacity	235
Unsecured Debt [Member]
Fiscal Year Maturities of Long-term Debt
Line of credit facility, maximum borrowing capacity	$ 50
Subordinated term loan | Subordinated Notes Due May 2030
Fiscal Year Maturities of Long-term Debt
Debt Instrument, Face Amount			$ 100
Minimum | Note Payable, 1.00% | Subsidiaries
Debt Instrument
Stated interest rate	1%
Maximum [Member] | Note Payable, Three Point Two Five Percent | Subsidiaries
Debt Instrument
Stated interest rate	3.25%

Subordinated Debentures Held _2

Subordinated Debentures Held by Subsidiary Trusts (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) trusts	Dec. 31, 2022 USD ($)	May 31, 2020	Nov. 01, 2007	Jun. 22, 2005
Subordinated Borrowing
Number of company sponsored wholly-owned business trusts | trusts	14
Stated interest rate			5.25%
Subordinated Debt	$ 163.7	$ 163.7
Subordinated Long-term Debt, Noncurrent		163.1
Common Stock Held in Assets	5.3	5.3
Subordinated Debt Fair Value Adjustment	(0.6)	(0.6)
Subordinated debentures held by subsidiary trusts	163.1	163.1
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II
Subordinated Borrowing
Subordinated Debt	2
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I
Subordinated Borrowing
Subordinated Debt	5
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI
Subordinated Borrowing
Subordinated Debt	30
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV
Subordinated Borrowing
Subordinated Debt	22.4
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III
Subordinated Borrowing
Subordinated Debt	5
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV
Subordinated Borrowing
Subordinated Debt	7
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V
Subordinated Borrowing
Subordinated Debt	5
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI
Subordinated Borrowing
Subordinated Debt	2
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II
Subordinated Borrowing
Common Stock Held in Assets	0.1	0.1
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II | Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II
Subordinated Borrowing
Subordinated Debt	$ 2.1	2.1
Debt instrument, basis spread on variable rate	1.85%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II | Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust II | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	7.50%
Junior Subordinated Deferrable Interest Debentures Issued by FIST II
Subordinated Borrowing
Common Stock Held in Assets	$ 0.3	0.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST II | Junior Subordinated Deferrable Interest Debentures Issued by FIST II
Subordinated Borrowing
Subordinated Debt	$ 10.3	10.3
Debt instrument, basis spread on variable rate	2.25%
Junior Subordinated Deferrable Interest Debentures Issued by FIST II | Junior Subordinated Deferrable Interest Debentures Issued by FIST II | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	7.91%
Junior Subordinated Deferrable Interest Debentures Issued by FIST I
Subordinated Borrowing
Common Stock Held in Assets	$ 0.5	0.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Junior Subordinated Deferrable Interest Debentures Issued by FIST I
Subordinated Borrowing
Subordinated Debt	$ 15.5	15.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.40%
Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate	2.75%
Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Junior Subordinated Deferrable Interest Debentures Issued by FIST I | Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate				7.50%
Junior Subordinated Deferrable Interest Debentures Issued by FIST III
Subordinated Borrowing
Common Stock Held in Assets	$ 0.6	0.6
Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Junior Subordinated Deferrable Interest Debentures Issued by FIST III
Subordinated Borrowing
Subordinated Debt	$ 20.6	20.6
Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.05%
Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate	2.40%
Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Junior Subordinated Deferrable Interest Debentures Issued by FIST III | Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate					6.88%
Junior Subordinated Deferrable Interest Debentures Issued by FIST IV
Subordinated Borrowing
Common Stock Held in Assets	$ 0.5	0.5
Junior Subordinated Deferrable Interest Debentures Issued by FIST IV | Junior Subordinated Deferrable Interest Debentures Issued by FIST IV
Subordinated Borrowing
Subordinated Debt	$ 15.5	15.5
Debt instrument, basis spread on variable rate	2.70%
Junior Subordinated Deferrable Interest Debentures Issued by FIST IV | Junior Subordinated Deferrable Interest Debentures Issued by FIST IV | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.36%
Junior Subordinated Deferrable Interest Debentures Issued by FIST V
Subordinated Borrowing
Common Stock Held in Assets	$ 0.3	0.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Junior Subordinated Deferrable Interest Debentures Issued by FIST V
Subordinated Borrowing
Subordinated Debt	$ 10.3	10.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.41%
Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate	2.75%
Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Junior Subordinated Deferrable Interest Debentures Issued by FIST V | Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate					6.78%
Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Common Stock Held in Assets	$ 0.3	0.3
Junior Subordinated Deferrable Interest Debentures Issued by FIST VI | Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Subordinated Debt	$ 10.3	10.3
Debt instrument, basis spread on variable rate	2.75%
Junior Subordinated Deferrable Interest Debentures Issued by FIST VI | Junior Subordinated Deferrable Interest Debentures Issued by FIST VI | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.41%
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I
Subordinated Borrowing
Common Stock Held in Assets	$ 0.2	0.2
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I
Subordinated Borrowing
Subordinated Debt	$ 5.2	5.2
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	7.29%
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate	1.70%
Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Junior Subordinated Deferrable Interest Debentures Issued by INB Cap Trust I | Debt Instrument, Redemption, At Issuance through Year Five [Member]
Subordinated Borrowing
Stated interest rate					5.95%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI
Subordinated Borrowing
Common Stock Held in Assets	$ 0.9	0.9
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI | Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI
Subordinated Borrowing
Subordinated Debt	$ 30.9	30.9
Debt instrument, basis spread on variable rate	1.48%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI | Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust VI | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	7.13%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV
Subordinated Borrowing
Common Stock Held in Assets	$ 0.7	0.7
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV | Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV
Subordinated Borrowing
Subordinated Debt	$ 23.1	23.1
Debt instrument, basis spread on variable rate	2.85%
Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV | Junior Subordinated Deferrable Interest Debentures Issued by GWB Trust IV | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.49%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III
Subordinated Borrowing
Common Stock Held in Assets	$ 0.2	0.2
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III | Junior Subordinated Deferrable Interest Debentures Issued by HFFC III
Subordinated Borrowing
Subordinated Debt	$ 5.2	5.2
Debt instrument, basis spread on variable rate	3.35%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC III | Junior Subordinated Deferrable Interest Debentures Issued by HFFC III | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	9.01%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV
Subordinated Borrowing
Common Stock Held in Assets	$ 0.2	0.2
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV | Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV
Subordinated Borrowing
Subordinated Debt	$ 7.2	7.2
Debt instrument, basis spread on variable rate	3.10%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV | Junior Subordinated Deferrable Interest Debentures Issued by HFFC IV | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	8.76%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V
Subordinated Borrowing
Common Stock Held in Assets	$ 0.3	0.3
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V | Junior Subordinated Deferrable Interest Debentures Issued by HFFC V
Subordinated Borrowing
Subordinated Debt	$ 5.3	5.3
Debt instrument, basis spread on variable rate	1.83%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC V | Junior Subordinated Deferrable Interest Debentures Issued by HFFC V | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	7.47%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI
Subordinated Borrowing
Common Stock Held in Assets	$ 0.2	0.2
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI | Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI
Subordinated Borrowing
Subordinated Debt	$ 2.2	$ 2.2
Debt instrument, basis spread on variable rate	1.65%
Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI | Junior Subordinated Deferrable Interest Debentures Issued by HFFC VI | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Subordinated Borrowing
Debt instrument, interest rate at period end	7.31%
Trust Preferred Securities Subject to Mandatory Redemption | Trusts
Subordinated Borrowing
Business trust term (in years)	30 years
Common Stock Subject to Mandatory Redemption | Trusts
Subordinated Borrowing
Amount of financial instruments subject to mandatory redemption	$ 5.3
Subordinated Debentures Subject to Mandatory Redemption | Trusts
Subordinated Borrowing
Business trust term (in years)	30 years

Capital Stock and Dividend Re_2

Capital Stock and Dividend Restrictions - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
	Dec. 14, 2023	Feb. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	May 25, 2023	Mar. 24, 2022	Dec. 14, 2021
Class of Stock
Common stock, shares authorized			150,000,000				250,000,000
Common stock, shares, outstanding			103,941,626	104,442,023
Stock compensation expense			$ 4.7	$ 9.6	$ 8.9
Payments for Repurchase of Common Stock	$ 32.1		$ 34	$ 199	$ 5.4
Stock Repurchased and Retired During Period, Shares			1,056,191	5,040,896	128,171
Sale of Stock Shares Authorized For Future Sale								47,158,390
Preferred Stock, Shares Authorized			100,000	100,000
Capital Stock, Authorized			150,100,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized						2,000,000,000,000
Great Western Bank
Class of Stock
Total consideration paid		$ 1,723.3
Class A Common Stock
Class of Stock
Stock Repurchased and Retired During Period, Shares				5,000,000,000,000
Class A Common Stock
Class of Stock
Common stock, shares authorized							150,000,000
Common Stock, Voting Rights, Votes Per Share			$ 1
Common stock, shares, outstanding				104,442,023
Class A Common Stock | Great Western Bank
Class of Stock
Common stock issued (in shares)		46,879,601
Class B Common Stock
Class of Stock
Common stock, shares authorized							100,000,000
Director [Member] | Class A Common Stock
Class of Stock
Shares issued to directors during period			54,414
Stock compensation expense			$ 1.2
Board of Directors
Class of Stock
Aggregate value of shares issued to directors				$ 1.3
Board of Directors | Class A Common Stock
Class of Stock
Shares issued to directors during period				33,769

Earnings per Common Share Compu

Earnings per Common Share Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Net income		$ 257.5	$ 202.2	$ 192.1
Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract]
Weighted average common shares outstanding for basic earnings per share computation		103,752,206	103,274,070	61,650,312
Dilutive effect of stock-based compensation (in shares)		27,897	66,929	91,516
Weighted average common shares outstanding for diluted earnings per common share computation		103,780,103	103,340,999	61,741,828
Restricted Stock [Member]
Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)		119,144	52,027	83,952
Performance Shares
Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	470,622	908,476		333,767

Regulatory Capital - Schedule o

Regulatory Capital - Schedule of Actual Capital Amounts and Ratios and Selected Minimum Regulatory Thresholds (Details) $ in Millions	Jan. 01, 2020 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Total risk-based capital:
Actual amount		$ 2,941.1	$ 2,875.8
Capital to Risk Weighted Assets		0.1328	0.1248
Adequately capitalized Basel III phase-in schedule, amount		$ 1,771.6	$ 1,843.2
Adequately capitalized Basel III phase-in schedule, ratio (percent)		0.0800	0.0800
Adequately capitalized Basel III fully phased-in, amount		$ 2,325.2	$ 2,419.2
Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets		10.50%	10.50%
Well capitalized, amount		$ 2,214.5	$ 2,304
Capital Required to be Well Capitalized to Risk Weighted Assets		0.1000	0.1000
Tier 1 risk-based capital:
Actual amount		$ 2,454.4	$ 2,408.8
Tier One Risk Based Capital to Risk Weighted Assets		0.1108	0.1045
Adequately capitalized Basel III phase-in schedule, amount		$ 1,328.7	$ 1,382.4
Adequately capitalized Basel III phase-in schedule, ratio (percent)		0.0600	0.0600
Adequately capitalized Basel III fully phased-in, amount		$ 1,882.3	$ 1,958.4
Tier One Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets		8.50%	8.50%
Well capitalized, amount		$ 1,771.6	$ 1,843.2
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets		0.0800	0.0800
Common Equity Tier One Capital [Abstract]
Actual amount		$ 2,454.4	$ 2,408.8
Common Equity Tier One Risk Based Capital To Risk Weighted Assets		11.08%	10.45%
Adequately capitalized Basel III phase-in schedule, amount		$ 996.5	$ 1,036.8
Adequately capitalized Basel III phase-in schedule, ratio (percent)		4.50%	4.50%
Adequately capitalized Basel III fully phased-in, amount		$ 1,550.1	$ 1,612.8
Tier One Common Equity Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets		7%	7%
Well capitalized, amount		$ 1,439.4	$ 1,497.6
Common Equity Tier One Capital To Be Well Capitalized To Risk Weighted Assets		6.50%	6.50%
Leverage capital ratio:
Actual amount		$ 2,454.4	$ 2,408.8
Tier One Leverage Capital to Average Assets		0.0822	0.0775
Adequately capitalized, amount		$ 1,193.9	$ 1,242.9
Adequately capitalized, ratio (percent)		0.0400	0.0400
Well capitalized, amount		$ 1,492.3	$ 1,553.6
Well capitalized, ratio (percent)		0.0500	0.0500
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle	$ 24.1
FIB
Total risk-based capital:
Actual amount		$ 2,662	$ 2,713.5
Capital to Risk Weighted Assets		0.1204	0.1180
Adequately capitalized Basel III phase-in schedule, amount		$ 1,768.3	$ 1,839.6
Adequately capitalized Basel III phase-in schedule, ratio (percent)		0.0800	0.0800
Adequately capitalized Basel III fully phased-in, amount		$ 2,320.8	$ 2,414.5
Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets		10.50%	10.50%
Well capitalized, amount		$ 2,210.3	$ 2,299.5
Capital Required to be Well Capitalized to Risk Weighted Assets		0.1000	0.1000
Tier 1 risk-based capital:
Actual amount		$ 2,433	$ 2,504.1
Tier One Risk Based Capital to Risk Weighted Assets		0.1101	0.1089
Adequately capitalized Basel III phase-in schedule, amount		$ 1,326.2	$ 1,379.7
Adequately capitalized Basel III phase-in schedule, ratio (percent)		0.0600	0.0600
Adequately capitalized Basel III fully phased-in, amount		$ 1,878.8	$ 1,954.6
Tier One Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets		8.50%	8.50%
Well capitalized, amount		$ 1,768.3	$ 1,839.6
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets		0.0800	0.0800
Common Equity Tier One Capital [Abstract]
Actual amount		$ 2,433	$ 2,504.1
Common Equity Tier One Risk Based Capital To Risk Weighted Assets		11.01%	10.89%
Adequately capitalized Basel III phase-in schedule, amount		$ 994.6	$ 1,034.8
Adequately capitalized Basel III phase-in schedule, ratio (percent)		4.50%	4.50%
Adequately capitalized Basel III fully phased-in, amount		$ 1,547.2	$ 1,609.7
Tier One Common Equity Capital Required For Capital Adequacy Under Basel III Fully Phased-In To Risk Weighted Assets		7%	7%
Well capitalized, amount		$ 1,436.7	$ 1,494.7
Common Equity Tier One Capital To Be Well Capitalized To Risk Weighted Assets		6.50%	6.50%
Leverage capital ratio:
Actual amount		$ 2,433	$ 2,504.1
Tier One Leverage Capital to Average Assets		0.0816	0.0807
Adequately capitalized, amount		$ 1,192.2	$ 1,241.1
Adequately capitalized, ratio (percent)		0.0400	0.0400
Well capitalized, amount		$ 1,490.2	$ 1,551.4
Well capitalized, ratio (percent)		0.0500	0.0500

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Unrecorded Unconditional Purchase Obligation
Operating leases, rent expense			$ 4.3
Operating Lease, Expense	$ 9.3	$ 8.9
Assets	30,671.2	32,287.8
Construction Contracts
Unrecorded Unconditional Purchase Obligation
Commitments under construction contracts	$ 4.5
Related Entity
Unrecorded Unconditional Purchase Obligation
Ownership percentage in partnership	50%
Mortgage loans originated for sale
Unrecorded Unconditional Purchase Obligation
Guarantor Obligations, Current Carrying Value	$ 0.8	$ 0.9

Commitments and Contingencies_2

Commitments and Contingencies - Operating Lease Commitments (Details) $ in Millions	Dec. 31, 2023 USD ($)
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	$ 50.6
Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	46.8
Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	3.8
Payments due within year one
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	11.6
Payments due within year one | Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	10.2
Payments due within year one | Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	1.4
Payments due year 2
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	9.9
Payments due year 2 | Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	8.5
Payments due year 2 | Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	1.4
Payments due year 3
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	8.1
Payments due year 3 | Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	7.2
Payments due year 3 | Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	0.9
Payments due year 4
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	5.5
Payments due year 4 | Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	5.4
Payments due year 4 | Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	0.1
Payments due year 5
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	4.2
Payments due year 5 | Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	4.2
Payments due year 5 | Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	0
Payments due after year 5
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	11.3
Payments due after year 5 | Commitments
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	11.3
Payments due after year 5 | Related Entity
Schedule of Future Minimum Rental Commitments
Operating leases, rent expense	$ 0

Financial Instruments with Of_2

Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Entity Information
Off-Balance Sheet, Credit Loss, Liability	$ 18.4	$ 16.2	$ 3.8
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	(31.1)	(68.4)	$ 14.7
Cumulative Effect, Period of Adoption, Adjusted Balance
Entity Information
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	2.2	12.4
Unused Credit Card Lines
Entity Information
Credit extension commitments	814	827.6
Standby Letters of Credit
Entity Information
Credit extension commitments	97.1	93.8
Commitments to Extend Credit
Entity Information
Credit extension commitments	$ 4,069.2	$ 5,173.3

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 46.1	$ 45.2	$ 39.4
State	12.8	14.4	11.3
Total current	58.9	59.6	50.7
Deferred:
Federal	16	(3.7)	3.7
State	4.4	(1)	1.3
Total deferred	20.4	(4.7)	5
Total income tax expense	79.3	54.9	55.7
Operating Loss Carryforwards [Line Items]
Deficiency (benefit) of stock-based compensation plans	0.3	0.2	(0.5)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	0	2	0.8
Federal tax credits	(0.2)	(4.3)	(4.3)
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ 2	$ 1.6	$ 0

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Tax Expense at Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Expense, Continuing Operations Income Tax Reconciliation [Abstract]
Tax expense at the statutory tax rate	$ 70.7	$ 54	$ 52
Increase (decrease) in tax resulting from:
Tax-exempt income	(8.1)	(8.4)	(2.8)
State income tax, net of federal income tax benefit	13.6	10.6	9.9
Deficiency (benefit) of stock-based compensation plans	0.3	0.2	(0.5)
Federal tax credits	(0.2)	(4.3)	(4.3)
Other, net	1	(0.8)	0.6
Total income tax expense	$ 79.3	$ 54.9	$ 55.7

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Loans, principally due to allowance for credit losses	$ 56.7	$ 54.8
Loan discount	21.7	32.5
Investment securities, unrealized losses	118.1	157.9
Deferred compensation	18.6	26.8
Non-performing loan interest	2.2	2.6
Net operating loss carryforwards	1.1	1.5
Lease liabilities	11	12
Other	4.8	2.4
Deferred tax assets	264.2	323.2
Deferred tax liabilities:
Fixed assets, principally differences in bases and depreciation	(19.8)	(17.3)
Deferred loan costs	(4.1)	(3.3)
Investment in joint venture partnership, principally due to differences in depreciation of partnership assets	(2.4)	(1.3)
Right of use assets	(10.3)	(11.3)
Prepaid amounts	(0.9)	(0.9)
Government agency stock dividends	(1.3)	(1.2)
Goodwill and other intangibles	(68.1)	(68.2)
Mortgage servicing rights	(6.9)	(7.4)
Other	(0.4)	(1.8)
Deferred tax liabilities	(114.2)	(112.7)
Deferred Tax Liabilities, Net	150	210.5
Operating Loss Carryforwards [Line Items]
Deferred Income Tax Expense (Benefit)	20.4	(4.7)	$ 5
Tax Credit Carryforward, Amount	2.4
Other real estate owned write-downs and carrying costs	1.4	1.5
Deferred Tax Assets, Derivative Instruments	0.3	0.5
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Reserves	10.7	8.8
Deferred Tax Assets, Contract Incentives	7.5	8.5
Deferred Tax Assets, Discount on Acquired Investment Securities	$ 10.1	$ 13.4

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Current net income tax receivable	$ 16.4	$ 38.3

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 4.7	$ 9.6	$ 8.9
Common Stock Including Additional Paid in Capital [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 4.7	9.6	8.9
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 4 months 6 days
Tax benefits from stock-based compensation	$ (0.4)	$ (0.3)	$ (0.3)
Stock issued during period, shares, restricted stock award	683,574			(86,802)
Unrecognized compensation cost related to nonvested restricted stock awards	$ 22.2
Restricted Stock [Member] | Upon Achievement of Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	363,440
Restricted Stock [Member] | Upon Achievement of Defined Return on Equity Performance Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	181,720
Restricted Stock [Member] | Upon Achievement of Defined Total Return to Shareholder Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	181,720
Restricted Stock [Member] | Time-restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	406,936
Restricted Stock [Member] | One Year from Grant Date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	54,414
Restricted Stock [Member] | Upon One-Third Annual Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	254,857
Restricted Stock [Member] | Two Year from Grant Date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	97,665
2006 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	1,389,724

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 4.7	$ 9.6	$ 8.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Ending Balance	$ 3,227.5	$ 3,073.8	1,986.6	$ 1,959.8
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	683,574			(86,802)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, beginning of year, number of shares	741,098
Granted, number of shares	683,574
Vested, number of shares	(180,587)
Forfeited, number of shares	(127,779)
Restricted stock, end of year, number of shares	1,116,306	741,098
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Restricted stock, beginning of year, weighted-average measurement date fair value (in dollars per share)	$ 38.94
Granted, weighted average grant date fair value (in dollars per share)	19.84
Vested, weighted average grant date fair value (in dollars per share)	36.73
Forfeited, weighted average grant date fair value (in dollars per share)	29.75
Restricted stock, end of year, weighted-average measurement date fair value (in dollars per share)	$ 27.74	$ 38.94
Tax benefits from stock-based compensation	$ (0.4)	$ (0.3)	(0.3)
Unrecognized compensation cost related to nonvested restricted stock awards	$ 22.2
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 4 months 6 days
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 4.7	9.6	8.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Ending Balance	$ 2,448.9	$ 2,478.2	$ 945	$ 941.1
Upon Achievement of Defined Total Return to Shareholder Goals | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	181,720
Upon One-Third Annual Anniversary | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	254,857
Upon Achievement of Performance Goals | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	363,440
Upon Achievement of Defined Return on Equity Performance Goals | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	181,720
One Year from Grant Date | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	54,414
Time-restricted shares | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued during period, shares, restricted stock award	406,936

Employee Benefit Plans - Profit

Employee Benefit Plans - Profit Sharing and Savings Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Other Comprehensive Income (Loss), Tax	$ 40,100,000	$ (155,200,000)	$ (22,800,000)
Savings Plan, Employee Elected
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Compensation expense	12,700,000	$ 13,500,000	$ 8,800,000
Maximum annual contribution per employee, amount per dollar of employee contribution	0.06
Savings Plan, Company Elected
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits
Maximum annual contribution per employee, amount per dollar of employee contribution	$ 1

Other Comprehensive Income - Sc

Other Comprehensive Income - Schedule of Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Other comprehensive income (loss), before tax	$ 160.7	$ (621.3)	$ (90.4)
Other Comprehensive Income (Loss), Tax	40.1	(155.2)	(22.8)
Other Comprehensive Income (Loss), Net of Tax	120.6	(466.1)	(67.6)
Before Tax Amount
Change in net unrealized gain during period	144.8	(613.1)	(113.7)
Reclassification adjustment for net losses included in net income	23.5	24.4	(1.1)
Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale	(7.2)	0.2	0
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), before Tax	(1.3)	(26.1)	20.2
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0.6	(4.9)	3.1
OCI, Debt Securities, Available-for-Sale, Gain (Loss), before Adjustment, Tax	0.9	(6.7)	4.2
Tax Expense (Benefit)
Change in net unrealized loss during period	36.1	(152.4)	(28.7)
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), Tax	(0.3)	(6.6)	5.1
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	0.3	(1.8)	1.1
Reclassification adjustment for net losses included in net income	5.8	5.5	(0.3)
Net of Tax Amount
Change in net unrealized loss during period	108.7	(460.7)	(85)
Reclassification adjustment for net gains included in net income	17.7	18.9	(0.8)
OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), after Tax	(1)	(19.5)	15.1
Stockholders' Equity Attributable to Parent	3,227.5	3,073.8	$ 1,986.6	$ 1,959.8
Net change in unamortized (losses) gains on available-for-sale investment securities transferred into held-to-maturity	(7.2)	0.2
Other Comprehensive Income (Loss), Transfers From Available-For-Sale To Held-To-Maturity Securities, Tax	(1.8)	0.1
Other Comprehensive Income (Loss), Transfers From Available-For-Sale To Held-To-Maturity Securities, Net Of Tax	$ (5.4)	$ 0.1

Other Comprehensive Income - Ac

Other Comprehensive Income - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Change in net unrealized gain during period	$ 144.8	$ (613.1)	$ (113.7)
Reclassification adjustment for net losses included in net income	23.5	24.4	(1.1)
Accumulated other comprehensive income (loss)	3,227.5	3,073.8	1,986.6	$ 1,959.8
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0.6	(4.9)	3.1
Net unrealized loss on investment securities available-for-sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	(350.1)	(471)
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax	(5.6)	(4.5)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(0.8)	(1.6)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	$ (356.5)	$ (477.1)	$ (11)	$ 56.6

Condensed Financial Informati_3

Condensed Financial Information (Parent Company Only) - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed balance sheets:
Cash and cash equivalents	$ 578	$ 870.5
Investment in subsidiaries, at equity:
Other assets	268.4	348.7
Assets	30,671.2	32,287.8
Long-term debt	99	98.9
Subordinated debentures held by subsidiary trusts	163.1	163.1
Total liabilities	27,443.7	29,214
Stockholders’ equity	3,227.5	3,073.8	$ 1,986.6	$ 1,959.8
Total liabilities and stockholders’ equity	30,671.2	32,287.8
Parent Company
Condensed balance sheets:
Cash and cash equivalents	275.7	154.8
Investment in subsidiaries, at equity:
Equity method investments	3,062.2	2,985.8
Advances from subsidiaries, net	43.5	0.1
Other assets	147	240.7
Assets	3,528.4	3,381.4
Other liabilities	38.8	45.6
Subordinated debentures held by subsidiary trusts	163.1	163.1
Total liabilities	300.9	307.6
Stockholders’ equity	3,227.5	3,073.8
Total liabilities and stockholders’ equity	$ 3,528.4	$ 3,381.4

Condensed Financial Informati_4

Condensed Financial Information (Parent Company Only) - Condensed Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions
Salaries and benefits	$ 263.1	$ 282.1	$ 164.9
Interest expense	401.3	78.9	17.3
Acquisition related expenses	0	118.9	11.6
Income before income tax	336.8	257.1	247.8
Income tax benefit	79.3	54.9	55.7
Net income	257.5	202.2	192.1
Parent Company
Condensed Financial Statements, Captions
Dividends from subsidiaries	360	360	160
Other interest income	0.5	0.4	0
Other income, primarily management fees from subsidiaries	51.6	51.7	41.3
Total income	412.1	412.1	201.3
Salaries and benefits	34.5	40.6	36.4
Interest expense	18.4	12.6	8.2
Acquisition related expenses	0	62.3	11.6
Other operating expenses, net	22.5	25	17.6
Total expenses	75.4	140.5	73.8
Income before income tax	336.7	271.6	127.5
Income tax benefit	(4.2)	(18.9)	(7.6)
Income before undistributed earnings of subsidiaries	340.9	290.5	135.1
Undistributed (loss) earnings of subsidiaries	(83.4)	(88.3)	57
Net income	$ 257.5	$ 202.2	$ 192.1

Condensed Financial Informati_5

Condensed Financial Information (Parent Company Only) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions			12 Months Ended
	Dec. 14, 2023	Feb. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income			$ 257.5	$ 202.2	$ 192.1
Adjustments to reconcile net income to cash provided by operating activities:
Net cash provided by operating activities			428	534.4	282.3
Cash flows from investing activities:
Net cash used in investing activities			1,253.4	(949)	(2,120)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of stock issuance costs			0	0.1	0.4
Purchase and retirement of common stock	$ (32.1)		(34)	(199)	(5.4)
Dividends paid to common stockholders			(195.1)	(182.1)	(101.6)
Net cash used in financing activities			(1,973.9)	(1,059.7)	1,905.7
Net (decrease) increase in cash and cash equivalents			(292.5)	(1,474.3)	68
Cash and cash equivalents at beginning of period			870.5	2,344.8	2,276.8
Cash and cash equivalents at end of period			578	870.5	2,344.8
Parent Company
Cash flows from operating activities:
Net income			257.5	202.2	192.1
Adjustments to reconcile net income to cash provided by operating activities:
Undistributed earnings of subsidiaries			83.4	88.3	(57)
Stock-based compensation expense			4.6	9.6	8.9
Other, net			2.7	(151.2)	(3.2)
Net cash provided by operating activities			348.2	148.9	140.8
Cash flows from investing activities:
Acquisition of bank and bank holding company, net of cash and cash equivalents received			0	(0.8)	0
Net cash used in investing activities			0	(0.8)	0
Cash flows from financing activities:
Net increase in advances from subsidiaries			1.8	206.5	23.7
Proceeds from issuance of common stock, net of stock issuance costs			0	0.1	0.4
Purchase and retirement of common stock			(34)	(198.9)	(5.4)
Dividends paid to common stockholders			(195.1)	(182.1)	(101.6)
Net cash used in financing activities			(227.3)	(174.4)	(82.9)
Net (decrease) increase in cash and cash equivalents			120.9	(26.3)	57.9
Cash and cash equivalents at beginning of period			154.8	181.1	123.2
Cash and cash equivalents at end of period			$ 275.7	$ 154.8	$ 181.1
Great Western Bank
Cash flows from financing activities:
Stock Issued		$ 1,722.5

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring and Non-Recurring Basis (Details) $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	$ 19.2	$ 18.7
Deferred compensation plan liabilities	19.2	18.7
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0.5	6.9
Deferred compensation plan assets	19.2	18.7
Deferred compensation plan liabilities	19.2	18.7
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	5.5
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	16.5	12.7
US Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
US Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	224.7	642.7
US Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
State, county and municipal securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
State, county and municipal securities | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	219.8	263.7
State, county and municipal securities | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
US Government Agencies Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
US Government Agencies Debt Securities [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	168.5	198.9
US Government Agencies Debt Securities [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	210.4	228
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Corporate securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Corporate securities | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	236.4	241.5
Corporate securities | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Collateralized Loan Obligations | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Collateralized Loan Obligations | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,119.7	1,111.6
Collateralized Loan Obligations | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Commercial Mortgage Backed Securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Commercial Mortgage Backed Securities | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,105.6	1,351.2
Commercial Mortgage Backed Securities | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Residential Mortgage-Backed Securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Residential Mortgage-Backed Securities | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,366.9	1,558.3
Residential Mortgage-Backed Securities | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Collateralized Mortgage Obligations | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Collateralized Mortgage Obligations | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,189.5	1,350.2
Collateralized Mortgage Obligations | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	5,841.5	6,946.1
Deferred compensation plan assets	19.2	18.7
Deferred compensation plan liabilities	19.2	18.7
Estimated Fair Value | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0.5	12.4
Deferred compensation plan assets	19.2	18.7
Deferred compensation plan liabilities	19.2	18.7
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	5,841.5	6,946.1
Deferred compensation plan assets	19.2	18.7
Deferred compensation plan liabilities	19.2	18.7
Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Deferred compensation plan assets	0	0
Deferred compensation plan liabilities	0	0
Estimated Fair Value | Loans And Leases Receivable, Other Real Estate Owned [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	16.5	12.7
Estimated Fair Value | US Treasury Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	224.7	642.7
Estimated Fair Value | State, county and municipal securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	219.8	263.7
Estimated Fair Value | US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	168.5	198.9
Estimated Fair Value | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	210.4	228
Estimated Fair Value | Corporate securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	236.4	241.5
Estimated Fair Value | Collateralized Loan Obligations | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,119.7	1,111.6
Estimated Fair Value | Commercial Mortgage Backed Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,105.6	1,351.2
Estimated Fair Value | Residential Mortgage-Backed Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,366.9	1,558.3
Estimated Fair Value | Collateralized Mortgage Obligations | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,189.5	1,350.2
Interest Rate Swap | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Interest Rate Swap | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	37.3	45.1
Derivative liabilities	123.5	154.2
Interest Rate Swap | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Interest Rate Swap | Estimated Fair Value | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	37.3	45.1
Derivative liabilities	123.5	154.2
Interest Rate Lock Commitments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Interest Rate Lock Commitments [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0.1
Interest Rate Lock Commitments [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Interest Rate Lock Commitments [Member] | Estimated Fair Value | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0.1
Forward Contracts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Derivative liabilities	0
Forward Contracts [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0.1
Derivative liabilities	0.1
Forward Contracts [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Derivative liabilities	0
Forward Contracts [Member] | Estimated Fair Value | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0.1
Derivative liabilities	0.1
Interest Rate Collars | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Interest Rate Collars | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	3.6	5.4
Interest Rate Collars | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Interest Rate Collars | Estimated Fair Value | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	3.6	$ 5.4
Risk Participation Agreements | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0
Risk Participation Agreements | Significant Other Observable Inputs (Level 2) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0.1
Risk Participation Agreements | Significant Unobservable Inputs (Level 3) | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0
Risk Participation Agreements | Estimated Fair Value | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ 0.1
Valuation, Market Approach [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member] | Loans And Leases Receivable, Impaired Loans [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	1	0.45
Valuation, Market Approach [Member] | Measurement Input, Discount Rate [Member] | Maximum [Member] | Loans And Leases Receivable, Other Real Estate Owned [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	0.43	0.36
Valuation, Market Approach [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member] | Loans And Leases Receivable, Impaired Loans [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	(0.36)	(0.07)
Valuation, Market Approach [Member] | Measurement Input, Discount Rate [Member] | Weighted Average [Member] | Loans And Leases Receivable, Other Real Estate Owned [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset, Measurement Input	(0.48)	(0.22)

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Inputs, Quantitative Information (Details) $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	$ 5,841.5	$ 6,946.1
Quoted Prices in Active Markets for Identical Assets (Level 1) | Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	0	0
Significant Other Observable Inputs (Level 2) | Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	5,841.5	6,946.1
Significant Unobservable Inputs (Level 3) | Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	0	0
Loans And Leases Receivable, Impaired Loans [Member] | Estimated Fair Value | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	(52.6)	(39.1)
Loans And Leases Receivable, Impaired Loans [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	0	0
Loans And Leases Receivable, Impaired Loans [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	0	0
Loans And Leases Receivable, Impaired Loans [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans	$ (52.6)	$ (39.1)
Loans And Leases Receivable, Impaired Loans [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Minimum | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0	0
Loans And Leases Receivable, Impaired Loans [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	1	0.45
Loans And Leases Receivable, Impaired Loans [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	(0.36)	(0.07)
Loans And Leases Receivable, Other Real Estate Owned [Member] | Estimated Fair Value | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	$ (16.5)	$ (12.7)
Loans And Leases Receivable, Other Real Estate Owned [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	0	0
Loans And Leases Receivable, Other Real Estate Owned [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other real estate owned	$ (16.5)	$ (12.7)
Loans And Leases Receivable, Other Real Estate Owned [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Minimum | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0.10	0.15
Loans And Leases Receivable, Other Real Estate Owned [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0.43	0.36
Loans And Leases Receivable, Other Real Estate Owned [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	(0.48)	(0.22)
Mortgage loans originated for sale | Estimated Fair Value | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Fair Value Disclosure	$ 46.9	$ 67.5
Mortgage loans originated for sale | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans		0
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Fair Value Disclosure	0
Mortgage loans originated for sale | Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans		0
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Fair Value Disclosure	0
Mortgage loans originated for sale | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Collateral-dependent loans		$ (67.5)
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Fair Value Disclosure	$ 46.9
Mortgage loans originated for sale | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Minimum | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0.05	0.11
Mortgage loans originated for sale | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0.23	0.23
Mortgage loans originated for sale | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	(0.14)	(0.17)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Estimated Fair Value | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	$ (1)	$ (5.5)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	0	0
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	0	0
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Long-lived assets to be disposed of by sale	$ (1)	$ (5.5)
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Minimum | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0	0
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0	0.06
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Measurement Input, Discount Rate [Member] | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing Asset, Measurement Input	0	(0.03)

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - Carrying Amount - Fair Value, Nonrecurring [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Long Lived, Fair Value Disclosure		$ 0.2
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 52.6	39.1
Assets Held-for-sale, Long Lived, Fair Value Disclosure		$ 5.5
Long Lived Assets Held-for-sale, Description	1.0 million	5.7 million

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Estimated Fair Values of Financial Instruments by Level of Valuation Inputs (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Financial assets:
Held-to-maturity investment securities, estimated fair value	$ 2,874	$ 3,052.2
Derivative Assets, Estimated Fair Value	37.4	45.2
Deferred compensation plan assets	19.2	18.7
Financial liabilities:
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Deferred compensation plan liabilities	19.2	18.7
Carrying Amount
Financial assets:
Cash and cash equivalents	578	870.5
Estimated Fair Value	5,841.5	6,946.1
Held-to-maturity investment securities, estimated fair value	3,207.9	3,451.8
Accrued interest receivable	129.1	118.3
Mortgage servicing rights, net	28.3	31.1
Loans Held-for-sale, Fair Value Disclosure	47.4	79.9
Net loans held for investment	18,051.9	17,879.1
Derivative Assets, Estimated Fair Value	37.4	45.2
Deferred compensation plan assets	19.2	18.7
Total financial assets	27,940.7	29,440.7
Financial liabilities:
Total deposits, excluding time deposits	20,313.2	23,145.2
Time deposits	3,009.9	1,928.4
Securities sold under repurchase agreements	782.7	1,052.9
Federal Home Loan Bank Borrowings, Fair Value Disclosure	2,603	2,327
Accrued interest payable	52.2	14.5
Long-term debt	120.8	120.8
Subordinated debentures held by subsidiary trusts	163.1	163.1
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Deferred compensation plan liabilities	19.2	18.7
Total financial liabilities	27,191.4	28,930.2
Estimated Fair Value
Financial assets:
Cash and cash equivalents	578	870.5
Estimated Fair Value	5,841.5	6,946.1
Held-to-maturity investment securities, estimated fair value	2,874	3,052.2
Accrued interest receivable	129.1	118.3
Mortgage servicing rights, net	38.8	37.4
Loans Held-for-sale, Fair Value Disclosure	47.4	79.9
Net loans held for investment	17,334.4	17,552.1
Derivative Assets, Estimated Fair Value	37.4	45.2
Deferred compensation plan assets	19.2	18.7
Total financial assets	26,899.8	28,720.4
Financial liabilities:
Total deposits, excluding time deposits	20,313.2	23,145.2
Time deposits	2,981.7	1,876.1
Securities sold under repurchase agreements	782.7	1,052.9
Federal Home Loan Bank Borrowings, Fair Value Disclosure	2,603	2,327
Accrued interest payable	52.2	14.5
Long-term debt	115.6	116.3
Subordinated debentures held by subsidiary trusts	151.1	155.8
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Deferred compensation plan liabilities	19.2	18.7
Total financial liabilities	27,146	28,866.1
Quoted Prices in Active Markets for Identical Assets (Level 1) | Estimated Fair Value
Financial assets:
Cash and cash equivalents	578	870.5
Estimated Fair Value	0	0
Held-to-maturity investment securities, estimated fair value	0	0
Accrued interest receivable	0	0
Mortgage servicing rights, net	0	0
Loans Held-for-sale, Fair Value Disclosure	0	0
Net loans held for investment	0	0
Derivative Assets, Estimated Fair Value	0	0
Deferred compensation plan assets	0	0
Total financial assets	578	870.5
Financial liabilities:
Total deposits, excluding time deposits	20,313.2	23,145.2
Time deposits	0	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0	0
Accrued interest payable	0	0
Long-term debt	0	0
Subordinated debentures held by subsidiary trusts	0	0
Derivative Liabilities, Estimated Fair Value	0	0
Deferred compensation plan liabilities	0	0
Total financial liabilities	20,313.2	23,145.2
Significant Other Observable Inputs (Level 2) | Estimated Fair Value
Financial assets:
Cash and cash equivalents	0	0
Estimated Fair Value	5,841.5	6,946.1
Held-to-maturity investment securities, estimated fair value	2,874	3,052.2
Accrued interest receivable	129.1	118.3
Mortgage servicing rights, net	38.8	37.4
Loans Held-for-sale, Fair Value Disclosure	0.5	6.9
Net loans held for investment	17,281.8	17,513
Derivative Assets, Estimated Fair Value	37.4	45.2
Deferred compensation plan assets	19.2	18.7
Total financial assets	26,222.3	27,737.8
Financial liabilities:
Total deposits, excluding time deposits	0	0
Time deposits	2,981.7	1,876.1
Securities sold under repurchase agreements	782.7	1,052.9
Federal Home Loan Bank Borrowings, Fair Value Disclosure	2,603	2,327
Accrued interest payable	52.2	14.5
Long-term debt	115.6	116.3
Subordinated debentures held by subsidiary trusts	151.1	155.8
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Deferred compensation plan liabilities	19.2	18.7
Total financial liabilities	6,832.8	5,720.9
Significant Unobservable Inputs (Level 3) | Estimated Fair Value
Financial assets:
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Held-to-maturity investment securities, estimated fair value	0	0
Accrued interest receivable	0	0
Mortgage servicing rights, net	0	0
Loans Held-for-sale, Fair Value Disclosure	46.9	73
Net loans held for investment	52.6	39.1
Derivative Assets, Estimated Fair Value	0	0
Deferred compensation plan assets	0	0
Total financial assets	99.5	112.1
Financial liabilities:
Total deposits, excluding time deposits	0	0
Time deposits	0	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0	0
Accrued interest payable	0	0
Long-term debt	0	0
Subordinated debentures held by subsidiary trusts	0	0
Derivative Liabilities, Estimated Fair Value	0	0
Deferred compensation plan liabilities	0	0
Total financial liabilities	$ 0	$ 0

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Dec. 14, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction
Amount of loans removed due to changes in related parties		$ 7.5
Shares Acquired, Average Cost Per Share	$ 32.14
Payments for Repurchase of Common Stock	$ 32.1	34	$ 199	$ 5.4
Executive Officers, Directors, Shareholders Greater than Five Percent, and Related Entities and Individuals to Such Persons [Member]
Related Party Transaction
Loans and leases receivable, related parties		11.1	$ 18.9
New loans and advances on existing loans		5.8
Loan repayments		$ 6.1
Class A Common Stock
Related Party Transaction
Shares Acquired	1,000,000,000,000

Recent Authoritative Accounting

Recent Authoritative Accounting Guidance (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 3,227.5	$ 3,073.8	$ 1,986.6	$ 1,959.8
Off-Balance Sheet, Credit Loss, Liability	18.4	16.2	3.8
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 1,135.1	$ 1,072.7	$ 1,052.6	$ 962.1

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 26, 2024	Jan. 16, 2024	May 31, 2020
Subsequent Event [Line Items]
Stated interest rate			5.25%
Subsequent Event | Federal Reserve Bank Advances
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 1,000
Subsequent Event | Debt Instrument, Redemption, Period One
Subsequent Event [Line Items]
Stated interest rate		4.76%
Class A Common Stock | Subsequent Event
Subsequent Event [Line Items]
Dividends (in dollars per share)	$ 0.47