First Busey (BUSE) 10-Q 7 May 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	May 07, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	0-15950
Entity Registrant Name	FIRST BUSEY CORPORATION
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	37-1078406
Entity Address, Address Line One	100 W. University Ave.
Entity Address, City or Town	Champaign
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	61820
City Area Code	217
Local Phone Number	365-4544
Title of 12(b) Security	Common Stock, $.001 par value
Trading Symbol	BUSE
Security Exchange Name	NASDAQ
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		56,729,312
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Central Index Key	0000314489
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Cash and cash equivalents:
Cash and due from banks	$ 93,091	$ 134,680
Interest-bearing deposits	497,980	584,901
Total cash and cash equivalents	591,071	719,581
Debt securities available for sale	1,898,072	2,087,571
Debt securities held to maturity	862,218	872,628
Equity securities	9,790	9,812
Loans held for sale	6,827	2,379
Portfolio loans (net of ACL of $91,562 at March 31, 2024, and $91,740 at December 31, 2023)	7,496,515	7,559,294
Premises and equipment, net	121,506	122,594
Right of use assets	10,590	11,027
Goodwill	317,873	317,873
Other intangible assets, net	33,582	35,991
Cash surrender value of bank owned life insurance	182,105	182,975
Other assets	357,309	361,690
Total assets	11,887,458	12,283,415
Deposits:
Noninterest-bearing	2,784,338	2,834,655
Interest-bearing	7,175,853	7,456,501
Total deposits	9,960,191	10,291,156
Securities sold under agreements to repurchase	147,175	187,396
Short-term borrowings	0	12,000
Long-term debt	0	18,000
Subordinated notes, net of unamortized issuance costs	223,100	222,882
Junior subordinated debt owed to unconsolidated trusts	72,040	71,993
Lease liabilities	10,896	11,308
Other liabilities	191,405	196,699
Total liabilities	10,604,807	11,011,434
Outstanding commitments and contingent liabilities (see Notes 4 and 10)
Stockholders’ equity
Common stock, ($.001 par value; 100,000,000 shares authorized)	58	58
Additional paid-in capital	1,324,999	1,323,595
Retained earnings	248,412	237,197
AOCI	(222,190)	(218,803)
Total stockholders’ equity before treasury stock	1,351,279	1,342,047
Treasury stock at cost	(68,628)	(70,066)
Total stockholders’ equity	1,282,651	1,271,981
Total liabilities and stockholders’ equity	$ 11,887,458	$ 12,283,415
Shares
Common shares issued (in shares)	58,116,969	58,116,969
Less: Treasury shares (in shares)	(2,816,961)	(2,872,850)
Common shares outstanding (in shares)	55,300,008	55,244,119

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Portfolio loans, allowance for credit losses	$ 91,562	$ 91,740
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest income
Interest and fees on loans	$ 99,325	$ 89,775
Interest and dividends on investment securities:
Taxable interest income	19,597	19,599
Non-taxable interest income	340	743
Other interest income	6,471	988
Total interest income	125,733	111,105
Interest expense
Deposits	43,968	14,740
Federal funds purchased and securities sold under agreements to repurchase	1,372	1,222
Short-term borrowings	232	4,822
Long-term debt	296	454
Subordinated notes	3,109	3,097
Junior subordinated debt owed to unconsolidated trusts	989	913
Total interest expense	49,966	25,248
Net interest income	75,767	85,857
Provision for credit losses	5,038	953
Net interest income after provision for credit losses	70,729	84,904
Noninterest income
Mortgage revenue	746	288
Income on bank owned life insurance	1,419	1,652
Realized gain on the sale of mortgage servicing rights	7,465	0
Realized net gains (losses) on securities	(6,802)	4
Unrealized net gains (losses) recognized on equity securities	427	(620)
Other income	3,431	3,593
Total noninterest income	35,000	31,848
Noninterest expense
Salaries, wages, and employee benefits	42,090	40,331
Data processing	6,550	5,640
Net occupancy expense of premises	4,720	4,762
Furniture and equipment expenses	1,813	1,746
Professional fees	2,253	2,058
Amortization of intangible assets	2,409	2,729
Interchange expense	1,611	1,853
FDIC insurance	1,400	1,502
Other expense	7,923	9,782
Total noninterest expense	70,769	70,403
Income before income taxes	34,960	46,349
Income taxes	8,735	9,563
Net income	$ 26,225	$ 36,786
Basic earnings per common share (in dollars per share)	$ 0.47	$ 0.66
Diluted earnings per common share (in dollars per share)	0.46	0.65
Dividends declared per share of common stock (in dollars per share)	$ 0.24	$ 0.24
Wealth management fees
Noninterest income
Noninterest income	$ 15,549	$ 14,797
Fees for customer services
Noninterest income
Noninterest income	7,056	6,819
Payment technology solutions
Noninterest income
Noninterest income	$ 5,709	$ 5,315

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 26,225	$ 36,786
Unrealized/Unrecognized gains (losses) on debt securities:
Net unrealized holding gains (losses) on debt securities available for sale, net of taxes of $2,266, and $(8,749), respectively	(5,681)	21,944
Reclassification adjustment for realized (gains) losses on debt securities available for sale included in net income, net of taxes of $(1,939), and $1, respectively	4,863	(3)
Amortization of unrecognized losses on securities transferred to held to maturity, net of taxes of $(402), and $(483), respectively	1,009	1,210
Net change in unrealized/unrecognized gains (losses) on debt securities	191	23,151
Unrealized gains (losses) on cash flow hedges:
Net unrealized holding gains (losses) on cash flow hedges, net of taxes of $2,086, and $(1,214), respectively	(5,232)	3,050
Reclassification adjustment for realized (gains) losses on cash flow hedges included in net income, net of taxes of $(659), and ($516), respectively	1,654	1,293
Net change in unrealized gains (losses) on cash flow hedges	(3,578)	4,343
Net change in AOCI	(3,387)	27,494
Total comprehensive income (loss)	$ 22,838	$ 64,280

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Net unrealized holding gains (losses) on debt securities available for sale, net, tax expense (benefit)	$ (2,266)	$ 8,749
Reclassification adjustment for realized (gains) losses on debt securities available for sale included in net income, tax expense (benefit)	(1,939)	1
Amortization of unrealized losses on securities transferred to held to maturity, tax expense (benefit)	(402)	(483)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Net unrealized holding gains (losses) on cash flow hedges, tax expense (benefit)	(2,086)	1,214
Reclassification adjustment for realized (gains) losses on cash flow hedges included in net income, tax expense (benefit)	$ (659)	$ (516)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2022		55,279,124
Beginning balance at Dec. 31, 2022	$ 1,145,977	$ 58	$ 1,320,980	$ 168,769	$ (273,278)	$ (70,552)
Increase (decrease) in shareholders' equity
Net income	36,786			36,786
OCI, net of tax	27,494				27,494
Repurchase of stock (in shares)		(25,000)
Repurchase of stock	(534)					(534)
Issuance of treasury stock for ESPP (in shares)		30,360
Issuance of treasury stock for ESPP	525		(257)			782
Net issuance of treasury stock for RSU/DSU vesting and related tax (in shares)		8,977
Net issuance of treasury stock for RSU/PSU/DSU vesting and related tax	(100)		(331)			231
Net issuance of treasury stock for warrants exercised (in shares)		994
Net issuance of treasury stock for warrants exercised	9		(17)			26
Cash dividends on common stock	(13,268)			(13,268)
Stock dividend equivalents on RSUs	0		363	(363)
Stock-based compensation	1,669		1,669
Ending balance (in shares) at Mar. 31, 2023		55,294,455
Ending balance at Mar. 31, 2023	1,198,558	$ 58	1,322,407	191,924	(245,784)	(70,047)
Beginning balance (in shares) at Dec. 31, 2023		55,244,119
Beginning balance at Dec. 31, 2023	1,271,981	$ 58	1,323,595	237,197	(218,803)	(70,066)
Beginning balance (Accounting Standards Update 2023-02) at Dec. 31, 2023	(1,391)			(1,391)
Increase (decrease) in shareholders' equity
Net income	26,225			26,225
OCI, net of tax	(3,387)				(3,387)
Issuance of treasury stock for ESPP (in shares)		23,305
Issuance of treasury stock for ESPP	475		(124)			599
Net issuance of treasury stock for RSU/DSU vesting and related tax (in shares)		32,584
Net issuance of treasury stock for RSU/PSU/DSU vesting and related tax	(396)		(1,235)			839
Cash dividends on common stock	(13,259)			(13,259)
Stock dividend equivalents on RSUs	0		360	(360)
Stock-based compensation	2,403		2,403
Ending balance (in shares) at Mar. 31, 2024		55,300,008
Ending balance at Mar. 31, 2024	$ 1,282,651	$ 58	$ 1,324,999	$ 248,412	$ (222,190)	$ (68,628)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Statement of Stockholders' Equity [Abstract]
Accounting Standards Update [Extensible Enumeration]			Accounting Standards Update 2023-02
Cash dividends, common stock (in dollars per share)	$ 0.24	$ 0.24

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows provided by (used in) operating activities
Net income	$ 26,225	$ 36,786
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for credit losses	5,038	953
Amortization of intangible assets	2,409	2,729
Amortization of mortgage servicing rights	468	749
Amortization of NMTC	0	2,221
Depreciation and amortization of premises and equipment	2,378	2,371
Net amortization (accretion) on portfolio loans	1,629	1,803
Net amortization (accretion) of premium (discount) on investment securities	2,535	4,231
Net amortization (accretion) of premium (discount) on time deposits	(20)	(80)
Net amortization (accretion) of premium (discount) on FHLB advances and other borrowings	265	252
Impairment of OREO and other repossessed assets	0	113
Impairment of fixed assets held for sale	48	0
Impairment of mortgage servicing rights	1	1
Unrealized (gains) losses recognized on equity securities, net	(427)	620
(Gain) loss on sales of debt securities, net	6,802	(4)
(Gain) loss on sales of mortgage servicing rights	(7,465)	0
(Gain) loss on sales of loans, net	(269)	(159)
(Gain) loss on sales of OREO and other repossessed assets	(540)	0
(Gain) loss on sales of premises and equipment	(10)	(266)
(Gain) loss on life insurance proceeds	(394)	(707)
(Increase) decrease in cash surrender value of bank owned life insurance	(1,025)	(945)
Provision for deferred income taxes	0	(1,617)
Stock-based compensation	2,403	1,669
Proceeds from the sale of mortgage servicing rights	9,796	0
Mortgage loans originated for sale	(19,296)	(9,524)
Proceeds from sales of mortgage loans	15,241	8,219
(Increase) decrease in other assets	1,613	(2,119)
Increase (decrease) in other liabilities	(10,055)	(2,000)
Net cash provided by (used in) operating activities	37,350	45,296
Cash flows provided by (used in) investing activities
Purchases of equity securities	(177)	(14)
Purchases of debt securities available for sale	(780)	(2,449)
Proceeds from sales of equity securities	626	14
Proceeds from sales of debt securities available for sale	101,360	0
Proceeds from paydowns and maturities of debt securities held to maturity	11,154	11,708
Proceeds from paydowns and maturities of debt securities available for sale	79,104	107,492
Purchases of FHLB and other bank stock	0	(17,891)
Proceeds from the redemption of FHLB and other bank stock	0	6,086
Net (increase) decrease in loans	56,113	(60,807)
Cash paid for premiums on bank-owned life insurance	(70)	(76)
Proceeds from life insurance	2,359	2,026
Purchases of premises and equipment	(1,365)	(2,380)
Proceeds from disposition of premises and equipment	37	284
Proceeds from sales of OREO and other repossessed assets, including cash payments collected	600	42
Net cash provided by (used in) investing activities	248,961	44,035
Cash flows provided by (used in) financing activities
Net increase (decrease) in deposits	(330,945)	(270,031)
Net increase (decrease) in federal funds purchased and securities sold under agreements to repurchase	(40,221)	(18,829)
Net increase (decrease) in short-term borrowings	0	265,000
Repayment of other borrowings	(30,000)	(3,173)
Cash dividends paid	(13,259)	(13,268)
Purchase of treasury stock	0	(534)
Cash paid for withholding taxes on stock-based payments	(396)	(100)
Proceeds from stock warrants exercised	0	9
Net cash provided by (used in) financing activities	(414,821)	(40,926)
Net increase (decrease) in cash and cash equivalents	(128,510)	48,405
Cash and cash equivalents, beginning of period	719,581	227,164
Cash and cash equivalents, ending of period	591,071	275,569
Cash payments for:
Interest	51,676	19,961
Non-cash investing and financing activities:
OREO acquired in settlement of loans	$ 0	$ 64

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Nature of Operations First Busey Corporation, a Nevada corporation organized in 1980, is a $11.9 billion financial holding company headquartered in Champaign, Illinois. Busey’s common stock is traded on The Nasdaq Global Select Market under the symbol “BUSE.” First Busey operates and reports its business in three segments: Banking, Wealth Management, and FirsTech. • The Banking operating segment provides a full range of banking services to individual and corporate customers through its banking center network in Illinois; the St. Louis, Missouri metropolitan area; southwest Florida; and Indianapolis, Indiana. • The Wealth Management operating segment provides a full range of asset management, investment, brokerage, fiduciary, philanthropic advisory, tax preparation, and farm management services to individuals, businesses, and foundations. • The FirsTech operating segment provides comprehensive and innovative payment technology solutions including online, mobile, and voice-recognition bill payments; money management and credit card networks; direct debit services; lockbox remittance processing for payments made by mail; and walk-in payments. FirsTech also provides additional tools to help clients with billing, reconciliation, bill reminders, and treasury services. For additional information about First Busey's operating segments, see “ Note 15. Operating Segments and Related Information .” Basis of Financial Statement Presentation These unaudited consolidated financial statements and related notes should be read in conjunction with the audited consolidated financial statements included in Busey's 2023 Annual Report . These interim unaudited consolidated financial statements serve to update our 2023 Annual Report and may not include all information and notes necessary to constitute a complete set of financial statements. We prepared these unaudited consolidated financial statements in conformity with GAAP. We have eliminated intercompany accounts and transactions. We have also reclassified certain prior year amounts to conform to the current period presentation. These reclassifications did not have a material impact on our consolidated financial condition or results of operations. In our opinion, the unaudited consolidated financial statements reflect all normal, recurring adjustments needed to present fairly our results for the interim periods. The results of operations for interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. Use of Estimates In preparing the accompanying unaudited consolidated financial statements in conformity with GAAP, Busey’s management is required to make estimates and assumptions that affect the amounts reported in the financial statements and the disclosures provided. Actual results could differ from those estimates. Material estimates which are particularly susceptible to significant change in the near term relate to the fair value of debt securities available for sale, fair value of assets acquired and liabilities assumed in business combinations, goodwill, income taxes, and the determination of the ACL. Impact of Recently Adopted Accounting Standards In March 2023, the FASB issued ASU 2023‑02 “Investments—Equity Method and Joint Ventures (Topic 323),” permitting an election to use the proportional amortization method to account for equity investments made primarily for the purpose of receiving income tax credits and other income tax benefits, regardless of the tax credit program from which the income tax credits are received, provided that certain conditions are met. The proportional amortization method results in the cost of the investment being amortized in proportion to the income tax credits and other income tax benefits received, with the amortization of the investment and the income tax credits being presented net in the income statement as a component of income tax expense. Busey adopted this standard on a modified retrospective basis on January 1, 2024. Upon adoption, Busey recorded an after-tax decrease to retained earnings of $1.4 million for the cumulative effect of adopting ASU 2023‑02. This transition adjustment included a $2.4 million decrease in other assets, a $0.5 million decrease in other liabilities, and a $0.5 million increase in deferred tax assets. In March 2023, the FASB issued ASU 2023‑01 “Leases (Topic 842): Common Control Arrangements,” which requires amortization over the useful life of leasehold improvements (not the lease term) when the lease is between entities under common control, and any value of such leasehold improvements remaining at the end of the lease term is to be accounted for as a transfer between entities under common control. Busey adopted this standard on a prospective basis on January 1, 2024. Adoption of this standard did not have a material impact on Busey’s financial position or results of operations. In June 2022, the FASB issued ASU 2022-03 “Fair Value Measurements (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions,” which clarifies that contractual restrictions on the sale of equity securities are not considered in measuring the fair value of those equity securities, and further that contractual sale restrictions cannot be recognized and measured as a separate unit of account. Busey adopted this standard on a prospective basis on January 1, 2024. Adoption of this standard did not have a material impact on Busey’s financial position or results of operations. Recently Issued Accounting Standards Not Yet Adopted In March 2024, the FASB issued ASU 2024-01 “Compensation-Stock Compensation (Topic 718): Scope Application of Profits Interest and Similar Awards” to clarify that certain “profits interests” are within the scope of Topic 718 by amending the language and providing illustrative examples on how the scope guidance in paragraph 718-10-15-3 should be applied. This update is intended to improve clarity of the accounting standards codification, not to change the guidance. This update may be applied on a retrospective or prospective basis and will be effective for Busey for annual and interim periods beginning January 1, 2025. Early adoption is permitted. Busey is currently evaluating the potential effects of adoption of this ASU on its financial position and results of operations. In December 2023, the FASB issued ASU 2023‑09 “Income Taxes (Topic 740): Improvements to Income Tax Disclosures,” which requires more detailed disclosures of income taxes paid net of refunds received, income from continuing operations before income tax expense or benefit, and income tax expense from continuing operations. This standard is to be applied on a prospective basis, with retrospective application permitted, and will be effective for Busey for annual reporting periods beginning with the fiscal year ending December 31, 2025. Busey does not expect adoption of this standard to have a material impact on its financial position or results of operations. In November 2023, the FASB issued ASU 2023‑07 “Segment Reporting Topic 820): Improvements to Reportable Segment Disclosures” requiring enhanced disclosures related to significant segment expenses. This standard is to be applied on a retrospective basis and is effective for Busey for annual reporting periods beginning with the fiscal year ending December 31, 2024, and for interim reporting periods within fiscal years starting January 1, 2025. Busey does not expect adoption of this standard to have a material impact on the Company’s financial position or results of operations. In October 2023, the FASB issued ASU 2023‑06 “Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative” which aligns certain GAAP disclosure requirements with the SEC’s disclosure requirements, in order to better facilitate comparisons between entities that are subject to the SEC’s existing disclosures with entities that were not previously subject to the SEC’s requirements. Amendments in this update should be applied prospectively, and the effective date for Busey for each amendment in this ASU will be the date on which the SEC removes the related disclosure from Regulation S‑X or Regulation S‑K. Early adoption is prohibited. Busey does not expect adoption of this standard to have a material impact on its financial position or results of operations. Subsequent Events Busey has evaluated subsequent events for potential recognition and/or disclosure through the date the unaudited consolidated financial statements included in this Quarterly Report were issued. Busey issued a Form 8‑K on April 1 , 202 4 , announcing completion of its acquisition of M&M on that date. Merger consideration paid to M&M common stockholders was comprised of an aggregate of 1,429,304 shares of Busey common stock and an aggregate of $12.2 million in cash. For additional information about Busey’s acquisition of M&M, see “ Not e. 16 Acquisition .” There were no other significant events subsequent to the quarter ended March 31, 2024, through the filing date of these unaudited consolidated financial statements.

DEBT SECURITIES

DEBT SECURITIES	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
DEBT SECURITIES	DEBT SECURITIES Busey's portfolio of debt securities includes both available for sale and held to maturity securities. The tables below provide the amortized cost, unrealized gains and losses, and fair values of debt securities summarized by major category (dollars in thousands) : As of March 31, 2024 Amortized Unrealized Fair Gross Gains Gross Losses Debt securities available for sale U.S. Treasury securities $ 749 $ — $ (7) $ 742 Obligations of U.S. government corporations and agencies 5,777 1 (35) 5,743 Obligations of states and political subdivisions 1 168,997 20 (18,091) 150,926 Asset-backed securities 1,2 462,082 — (384) 461,698 Commercial mortgage-backed securities 108,006 — (15,443) 92,563 Residential mortgage-backed securities 1,223,453 2 (201,722) 1,021,733 Corporate debt securities 177,212 85 (12,630) 164,667 Total debt securities available for sale $ 2,146,276 $ 108 $ (248,312) $ 1,898,072 Amortized Unrecognized Fair Gross Gains Gross Losses Debt securities held to maturity Commercial mortgage-backed securities $ 424,946 $ — $ (74,590) $ 350,356 Residential mortgage-backed securities 437,272 — (74,597) 362,675 Total debt securities held to maturity $ 862,218 $ — $ (149,187) $ 713,031 ___________________________________________ 1. Includes securities marked at par, with no gain or loss to report. 2. Gross gains were insignificant, rounding to zero thousand. As of December 31, 2023 Amortized Unrealized Fair Gross Gains Gross Losses Debt securities available for sale U.S. Treasury securities $ 16,031 $ — $ (85) $ 15,946 Obligations of U.S. government corporations and agencies 5,889 1 (58) 5,832 Obligations of states and political subdivisions 1 190,819 52 (18,026) 172,845 Asset-backed securities 470,046 — (1,823) 468,223 Commercial mortgage-backed securities 119,044 — (15,535) 103,509 Residential mortgage-backed securities 1 1,306,854 5 (195,547) 1,111,312 Corporate debt securities 225,947 128 (16,171) 209,904 Total debt securities available for sale $ 2,334,630 $ 186 $ (247,245) $ 2,087,571 Amortized Unrecognized Fair Gross Gains Gross Losses Debt securities held to maturity Commercial mortgage-backed securities $ 428,526 $ — $ (71,000) $ 357,526 Residential mortgage-backed securities 444,102 — (71,231) 372,871 Total debt securities held to maturity $ 872,628 $ — $ (142,231) $ 730,397 ___________________________________________ 1. Includes securities marked at par, with no gain or loss to report. Maturities of Debt Securities Amortized cost and fair value of debt securities, by contractual maturity or pre-refunded date, are shown below. Mortgages underlying mortgage-backed securities and asset-backed securities may be called or prepaid; therefore, actual maturities could differ from the contractual maturities. All mortgage-backed securities were issued by U.S. government corporations and agencies (dollars in thousands) : As of March 31, 2024 Amortized Fair Debt securities available for sale Due in one year or less $ 262,012 $ 222,566 Due after one year through five years 752,610 666,718 Due after five years through ten years 529,926 469,029 Due after ten years 601,728 539,759 Debt securities available for sale $ 2,146,276 $ 1,898,072 Debt securities held to maturity Due in one year or less $ 104,797 $ 88,589 Due after one year through five years 263,376 216,744 Due after five years through ten years 241,243 198,562 Due after ten years 252,802 209,136 Debt securities held to maturity $ 862,218 $ 713,031 Gains and Losses on Debt Securities Available for Sale Realized gains and losses related to sales and calls of debt securities available for sale are summarized as follows (dollars in thousands) : Three Months Ended March 31, 2024 2023 Realized gains and losses on debt securities Gross gains on debt securities $ 1 $ 10 Gross (losses) on debt securities 1 (6,803) (6) Realized net gains (losses) on debt securities $ (6,802) $ 4 ___________________________________________ 1. During the first quarter of 2024, Busey sold available-for-sale debt securities with a book value of approximately $108.2 million for a pre-tax loss of $6.8 million, as part of a balance sheet repositioning strategy. The loss on the sale of securities was offset by a pre-tax gain of $7.5 million realized on the sale of mortgage servicing rights on approximately $923.5 million of one- to four-family mortgage loans. Debt securities with carrying amounts of $787.5 million on March 31, 2024, and $837.4 million on December 31, 2023, were pledged as collateral for public deposits, securities sold under agreements to repurchase, and for other purposes as required. Debt Securities in an Unrealized or Unrecognized Loss Position The following information pertains to debt securities with gross unrealized or unrecognized losses, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (dollars in thousands) : As of March 31, 2024 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Debt securities available for sale U.S. Treasury securities $ — $ — $ 742 $ (7) $ 742 $ (7) Obligations of U.S. government corporations and agencies — — 5,629 (35) 5,629 (35) Obligations of states and political subdivisions 8,524 (68) 134,945 (18,023) 143,469 (18,091) Asset-backed securities — — 253,231 (384) 253,231 (384) Commercial mortgage-backed securities — — 92,563 (15,443) 92,563 (15,443) Residential mortgage-backed securities 165 (1) 1,021,383 (201,721) 1,021,548 (201,722) Corporate debt securities 4,313 (102) 152,739 (12,528) 157,052 (12,630) Debt securities available for sale with gross unrealized losses $ 13,002 $ (171) $ 1,661,232 $ (248,141) $ 1,674,234 $ (248,312) 12 months or more Total Fair Unrecognized Fair Unrecognized Debt securities held to maturity Commercial mortgage-backed securities $ 350,356 $ (74,590) $ 350,356 $ (74,590) Residential mortgage-backed securities 362,675 (74,597) 362,675 (74,597) Debt securities held to maturity with gross unrecognized losses $ 713,031 $ (149,187) $ 713,031 $ (149,187) As of December 31, 2023 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Debt securities available for sale U.S. Treasury securities $ — $ — $ 15,946 $ (85) $ 15,946 $ (85) Obligations of U.S. government corporations and agencies — — 5,709 (58) 5,709 (58) Obligations of states and political subdivisions 11,442 (54) 146,797 (17,972) 158,239 (18,026) Asset-backed securities — — 468,223 (1,823) 468,223 (1,823) Commercial mortgage-backed securities — — 103,509 (15,535) 103,509 (15,535) Residential mortgage-backed securities 141 (1) 1,110,906 (195,546) 1,111,047 (195,547) Corporate debt securities 1,450 (10) 198,694 (16,161) 200,144 (16,171) Debt securities available for sale with gross unrealized losses $ 13,033 $ (65) $ 2,049,784 $ (247,180) $ 2,062,817 $ (247,245) 12 months or more Total Fair Unrecognized Fair Unrecognized Debt securities held to maturity Commercial mortgage-backed securities $ 357,526 $ (71,000) $ 357,526 $ (71,000) Residential mortgage-backed securities 372,871 (71,231) 372,871 (71,231) Debt securities held to maturity with gross unrecognized losses $ 730,397 $ (142,231) $ 730,397 $ (142,231) Additional information about debt securities in an unrealized or unrecognized loss position is presented in the tables below (dollars in thousands) : As of March 31, 2024 Available for Sale Held to Maturity Total Debt securities with gross unrealized or unrecognized losses, fair value $ 1,674,234 $ 713,031 $ 2,387,265 Gross unrealized or unrecognized losses on debt securities 248,312 149,187 397,499 Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses 14.8 % 20.9 % 16.7 % Count of debt securities 708 55 763 Count of debt securities in an unrealized or unrecognized loss position 654 55 709 As of December 31, 2023 Available for Sale Held to Maturity Total Debt securities with gross unrealized or unrecognized losses, fair value $ 2,062,817 $ 730,397 $ 2,793,214 Gross unrealized or unrecognized losses on debt securities 247,245 142,231 389,476 Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses 12.0 % 19.5 % 13.9 % Count of debt securities 835 55 890 Count of debt securities in an unrealized or unrecognized loss position 779 55 834 Unrealized and unrecognized losses were related to changes in market interest rates and market conditions that do not represent credit-related impairments. Unless part of a corporate strategy or restructuring plan, Busey does not intend to sell securities that are in an unrealized or unrecognized loss position, and it is more likely than not that the Company will recover the amortized cost prior to being required to sell the debt securities. Full collection of the amounts due according to the contractual terms of the debt securities is expected; therefore, no ACL was recorded in relation to debt securities, and the impairment related to noncredit factors on debt securities available for sale is recognized in AOCI, net of applicable taxes. As of March 31, 2024, Busey did not hold general obligation bonds of any single issuer, the aggregate of which exceeded 10% of Busey’s stockholders’ equity.

PORTFOLIO LOANS

PORTFOLIO LOANS	3 Months Ended
	Mar. 31, 2024
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
PORTFOLIO LOANS	PORTFOLIO LOANS Loan Categories Busey’s lending can be summarized in two primary categories: commercial and retail. Lending is further classified into five primary areas of loans: C&I and other commercial loans, commercial real estate loans, real estate construction loans, retail real estate loans, and retail other loans. Distributions of the loan portfolio by loan category and class is presented in the following table (dollars in thousands) : As of March 31, December 31, Commercial loans C&I and other commercial $ 1,828,711 $ 1,835,994 Commercial real estate 3,331,670 3,337,337 Real estate construction 445,860 461,717 Total commercial loans 5,606,241 5,635,048 Retail loans Retail real estate 1,708,663 1,720,455 Retail other 273,173 295,531 Total retail loans 1,981,836 2,015,986 Total portfolio loans 7,588,077 7,651,034 ACL (91,562) (91,740) Portfolio loans, net $ 7,496,515 $ 7,559,294 Net deferred loan origination costs included in the balances above were $13.4 million as of March 31, 2024, compared to $13.5 million as of December 31, 2023. Net accretable purchase accounting adjustments included in the balances above reduced loans by $4.3 million as of March 31, 2024, and $4.5 million as of December 31, 2023. Busey did not purchase any retail real estate loans during the three months ended March 31, 2024 or 2023. Pledged Loans The principal balance of loans Busey has pledged as collateral to the FHLB and Federal Reserve Bank for liquidity as set forth in the table below (dollars in thousands) : As of March 31, December 31, Pledged loans FHLB $ 4,821,485 $ 4,865,481 Federal Reserve Bank 724,971 722,914 Total pledged loans $ 5,546,456 $ 5,588,395 Risk Grading Busey utilizes a loan grading scale to assign a risk grade to all of its loans. A description of the general characteristics of each grade is as follows: • Pass – This category includes loans that are all considered acceptable credits, ranging from investment or near investment grade, to loans made to borrowers who exhibit credit fundamentals that meet or exceed industry standards. • Watch – This category includes loans that warrant a higher-than-average level of monitoring to ensure that weaknesses do not cause the inability of the credit to perform as expected. These loans are not necessarily a problem due to other inherent strengths of the credit, such as guarantor strength, but have above average concern and monitoring. • Special mention – This category is for “Other Assets Specially Mentioned” loans that have potential weaknesses, which may, if not checked or corrected, weaken the asset or inadequately protect Busey’s credit position at some future date. • Substandard – This category includes “Substandard” loans, determined in accordance with regulatory guidelines, for which the accrual of interest has not been stopped. Assets so classified must have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that Busey will sustain some loss if the deficiencies are not corrected. • Substandard non-accrual – This category includes loans that have all the characteristics of a “Substandard” loan with additional factors that make collection in full highly questionable and improbable. Such loans are placed on non-accrual status and may be dependent on collateral with a value that is difficult to determine. All loans are graded at their inception. Commercial lending relationships that are $1.0 million or less are usually processed through an expedited underwriting process. Most commercial loans greater than $1.0 million are included in a portfolio review at least annually. Commercial loans greater than $0.35 million that have a grading of special mention or worse are typically reviewed on a quarterly basis. Interim reviews may take place if circumstances of the borrower warrant a more frequent review. The following table is a summary of risk grades segregated by category and class of portfolio loans (dollars in thousands) : As of March 31, 2024 Pass Watch Special Substandard Substandard Total Commercial loans C&I and other commercial $ 1,491,166 $ 243,635 $ 37,711 $ 42,853 $ 13,346 $ 1,828,711 Commercial real estate 2,797,374 447,313 49,932 36,987 64 3,331,670 Real estate construction 410,089 22,483 7,743 5,301 244 445,860 Total commercial loans 4,698,629 713,431 95,386 85,141 13,654 5,606,241 Retail loans Retail real estate 1,692,013 9,371 922 2,689 3,668 1,708,663 Retail other 273,030 — — — 143 273,173 Total retail loans 1,965,043 9,371 922 2,689 3,811 1,981,836 Total portfolio loans $ 6,663,672 $ 722,802 $ 96,308 $ 87,830 $ 17,465 $ 7,588,077 As of December 31, 2023 Pass Watch Special Substandard Substandard Total Commercial loans C&I and other commercial $ 1,462,755 $ 296,416 $ 46,488 $ 27,733 $ 2,602 $ 1,835,994 Commercial real estate 2,827,030 431,427 48,545 29,492 843 3,337,337 Real estate construction 448,011 8,135 — 5,327 244 461,717 Total commercial loans 4,737,796 735,978 95,033 62,552 3,689 5,635,048 Retail loans Retail real estate 1,702,897 11,144 1,024 1,795 3,595 1,720,455 Retail other 295,374 — — — 157 295,531 Total retail loans 1,998,271 11,144 1,024 1,795 3,752 2,015,986 Total portfolio loans $ 6,736,067 $ 747,122 $ 96,057 $ 64,347 $ 7,441 $ 7,651,034 Risk grades of portfolio loans and gross charge-offs are presented in the tables below by loan class, further sorted by origination year (dollars in thousands) : As of and For The Three Months Ended March 31, 2024 Term Loans Amortized Cost Basis by Origination Year Revolving Total Risk Grade Ratings 2024 2023 2022 2021 2020 Prior C&I and other commercial Pass $ 92,898 $ 261,771 $ 214,944 $ 156,831 $ 66,161 $ 154,099 $ 544,462 $ 1,491,166 Watch 4,869 58,913 49,671 14,389 23,226 27,759 64,808 243,635 Special Mention 665 239 7,964 2,654 677 3,264 22,248 37,711 Substandard 8,371 5,700 1,386 819 525 2,348 23,704 42,853 Substandard non-accrual — 75 — 117 66 1,388 11,700 13,346 Total commercial 106,803 326,698 273,965 174,810 90,655 188,858 666,922 1,828,711 Gross charge-offs — 5,130 — — — 88 — 5,218 Commercial real estate Pass 77,146 362,541 845,621 676,837 384,545 433,216 17,468 2,797,374 Watch 58,049 131,059 35,873 111,998 32,964 73,846 3,524 447,313 Special Mention 1,405 8,646 13,126 12,578 5,015 9,162 — 49,932 Substandard 1,362 5,626 2,677 18,821 3,337 5,114 50 36,987 Substandard non-accrual — 44 — — 20 — — 64 Total commercial real estate 137,962 507,916 897,297 820,234 425,881 521,338 21,042 3,331,670 Gross charge-offs — — — — — 96 — 96 Real estate construction Pass 58,333 177,437 72,325 75,282 2,458 3,332 20,922 410,089 Watch — 3,678 18,030 455 320 — — 22,483 Special Mention — 7,743 — — — — — 7,743 Substandard — 5,301 — — — — — 5,301 Substandard non-accrual — — — — — 244 — 244 Total real estate construction 58,333 194,159 90,355 75,737 2,778 3,576 20,922 445,860 Gross charge-offs — — — — — — — — Retail real estate Pass 19,533 240,662 376,623 378,955 153,995 313,080 209,165 1,692,013 Watch 805 832 2,873 2,242 937 401 1,281 9,371 Special Mention — 191 354 — — 377 — 922 Substandard — 136 1,049 519 45 935 5 2,689 Substandard non-accrual — — 527 65 253 1,982 841 3,668 Total retail real estate 20,338 241,821 381,426 381,781 155,230 316,775 211,292 1,708,663 Gross charge-offs — — — — — 52 — 52 Retail other Pass 1,458 78,006 83,891 20,205 5,438 3,546 80,486 273,030 Substandard non-accrual — — 93 49 — 1 — 143 Total retail other 1,458 78,006 83,984 20,254 5,438 3,547 80,486 273,173 Gross charge-offs — 3 — 23 — 68 — 94 Total portfolio loans $ 324,894 $ 1,348,600 $ 1,727,027 $ 1,472,816 $ 679,982 $ 1,034,094 $ 1,000,664 $ 7,588,077 Total gross charge-offs $ — $ 5,133 $ — $ 23 $ — $ 304 $ — $ 5,460 As of and For The Year Ended December 31, 2023 Term Loans Amortized Cost Basis by Origination Year Revolving Total Risk Grade Ratings 2023 2022 2021 2020 2019 Prior C&I and other commercial Pass $ 306,578 $ 220,847 $ 159,130 $ 71,025 $ 35,927 $ 143,078 $ 526,170 $ 1,462,755 Watch 78,603 65,703 21,421 23,919 7,035 21,293 78,442 296,416 Special Mention 792 8,224 2,917 1,076 686 3,274 29,519 46,488 Substandard 8,715 765 942 426 3,734 1,859 11,292 27,733 Substandard non-accrual 166 — 117 84 128 407 1,700 2,602 Total commercial 394,854 295,539 184,527 96,530 47,510 169,911 647,123 1,835,994 Gross charge-offs 284 — 420 — 316 1,409 — 2,429 Commercial real estate Pass 395,644 824,506 720,052 399,195 271,078 199,662 16,893 2,827,030 Watch 166,795 47,070 92,848 34,010 68,196 19,396 3,112 431,427 Special Mention 14,313 10,507 12,446 4,968 3,297 3,014 — 48,545 Substandard 1,796 188 18,862 2,938 1,802 3,856 50 29,492 Substandard non-accrual 47 79 85 23 — 609 — 843 Total commercial real estate 578,595 882,350 844,293 441,134 344,373 226,537 20,055 3,337,337 Gross charge-offs — — — — — 953 — 953 Real estate construction Pass 204,952 128,462 85,086 2,616 1,323 2,934 22,638 448,011 Watch 2,859 4,406 507 322 41 — — 8,135 Substandard 5,327 — — — — — — 5,327 Substandard non-accrual — — — — — 244 — 244 Total real estate construction 213,138 132,868 85,593 2,938 1,364 3,178 22,638 461,717 Gross charge-offs — — — — — — — — Retail real estate Pass 243,400 376,922 411,723 156,762 70,099 256,571 187,420 1,702,897 Watch 1,096 4,137 2,442 954 536 234 1,745 11,144 Special Mention 286 358 — — — 380 — 1,024 Substandard 69 72 292 49 80 997 236 1,795 Substandard non-accrual — 528 121 267 100 1,960 619 3,595 Total retail real estate 244,851 382,017 414,578 158,032 70,815 260,142 190,020 1,720,455 Gross charge-offs — 5 — 29 72 301 — 407 Retail other Pass 88,885 92,931 23,019 6,701 4,597 854 78,387 295,374 Substandard non-accrual — 93 62 — — 2 — 157 Total retail other 88,885 93,024 23,081 6,701 4,597 856 78,387 295,531 Gross charge-offs 5 71 172 5 3 373 — 629 Total portfolio loans $ 1,520,323 $ 1,785,798 $ 1,552,072 $ 705,335 $ 468,659 $ 660,624 $ 958,223 $ 7,651,034 Total gross charge-offs $ 289 $ 76 $ 592 $ 34 $ 391 $ 3,036 $ — $ 4,418 Past Due and Non-accrual Loans An analysis of the amortized cost basis of portfolio loans that are past due and still accruing, or on a non-accrual status, is as follows (dollars in thousands) : As of March 31, 2024 Loans past due, still accruing Non-accrual 30-59 Days 60-89 Days 90+Days Past due and non-accrual loans Commercial loans: C&I and other commercial $ 43 $ — $ — $ 13,346 Commercial real estate 3,174 338 — 64 Real estate construction — — — 244 Past due and non-accrual commercial loans 3,217 338 — 13,654 Retail loans: Retail real estate 2,869 385 77 3,668 Retail other 530 102 11 143 Past due and non-accrual retail loans 3,399 487 88 3,811 Total past due and non-accrual loans $ 6,616 $ 825 $ 88 $ 17,465 As of December 31, 2023 Loans past due, still accruing Non-accrual 30-59 Days 60-89 Days 90+Days Past due and non-accrual loans Commercial loans: C&I and other commercial $ — $ 214 $ — $ 2,602 Commercial real estate 752 — — 843 Real estate construction 24 — — 244 Past due and non-accrual commercial loans 776 214 — 3,689 Retail loans: Retail real estate 2,781 927 366 3,595 Retail other 886 195 9 157 Past due and non-accrual retail loans 3,667 1,122 375 3,752 Total past due and non-accrual loans $ 4,443 $ 1,336 $ 375 $ 7,441 Gross interest income recorded on 90+ days past due loans, and that would have been recorded on non-accrual loans if they had been accruing interest in accordance with their original terms, was $0.3 million for the three months ended March 31, 2024, and was $0.4 million for the three months ended March 31, 2023. The amount of interest collected on those loans and recognized on a cash basis that was included in interest income was immaterial for the three months ended March 31, 2024 and 2023. Loan Modifications for Borrowers Experiencing Financial Difficulty The following tables present the amortized cost basis of loans that were modified—specifically in the form of (1) principal forgiveness, (2) an interest rate reduction, (3) an other-than-insignificant payment deferral, and/or (4) a term extension—for borrowers experiencing financial difficulty during the periods indicated, disaggregated by class of financing receivable and type of concession granted (dollars in thousands) : Three Months Ended March 31, 2024 Payment Deferral 1 % of Total Class of Financing Receivable Term Extension 2 % of Total Class of Financing Receivable Modified Loans C&I and other commercial $ 10,000 0.5 % $ 17,155 0.9 % Commercial real estate — — % 1,705 0.1 % Total of loans modified during the period $ 10,000 0.1 % $ 18,860 0.2 % ___________________________________________ 1. One loan was modified and classified as non-accrual during the three months ended March 31, 2024. 2. Modifications to extend loan terms also included, in some cases, interest rate increases during the extension period. All modifications were for loans classified as substandard. Three Months Ended March 31, 2023 Payment Deferral 1 % of Total Class of Financing Receivable 2 Term Extension 3 % of Total Class of Financing Receivable Modified Loans C&I and other commercial $ 489 — % $ 25,155 1.3 % Commercial real estate — — % 12,698 0.4 % Total of loans modified during the period 4 $ 489 — % $ 37,853 0.5 % ___________________________________________ 1. Loans with payment deferrals were modified to defer all principal payments until the end of the loan terms, which were shortened. Regular interest payments continue to be required during the deferral period. 2. Loans with payment deferrals represent an insignificant portion of commercial loans and total loans, rounding to zero percent. 3. Modifications to extend loan terms also included, in most cases, interest rate increases during the extension period. 4. All modifications were for loans classified as substandard. Three Months Ended March 31, 2024 2023 Weighted Average Term Extension Weighted Average Term Extension Effects of Loan Modifications C&I and other commercial 19.1 months 9.1 months Commercial real estate 2.0 months 5.8 months Total effect 17.6 months 8.0 months No loans to borrowers experiencing financial difficulty had a payment default during the three months ended March 31, 2024 or 2023, after having been modified during the 12 months before that default. A default occurs when a loan is 90 days or more past due or transferred to non-accrual status. Busey closely monitors the performance of the loans that are modified to borrowers experiencing financial difficulty to understand the effectiveness of its modification efforts. The following table depicts the payment performance of loans modified during the last twelve months (dollars in thousands) : As of March 31, 2024 Current 30-89 Days 90+ Days Non-accrual Modified Loans C&I and other commercial $ 21,641 $ — $ — $ 10,000 Commercial real estate 3,009 — — — Real estate construction 5,301 — — — Amortized cost of modified loans $ 29,951 $ — $ — $ 10,000 Collateral Dependent Loans Management's evaluation as to the ultimate collectability of loans includes estimates regarding future cash flows from operations and the value of property, real and personal, pledged as collateral. These estimates are affected by changing economic conditions and the economic prospects of borrowers. Collateral dependent loans are loans in which repayment is expected to be provided solely by the operation or sale of the underlying collateral and there are no other available and reliable sources of repayment. Loans are written down to the lower of cost or fair value of the underlying collateral, less estimated costs to sell. Busey had $14.2 million and $6.1 million of collateral dependent loans secured by real estate or business assets as of March 31, 2024, and December 31, 2023, respectively. Foreclosures As of March 31, 2024, Busey had $0.9 million of residential real estate loans in the process of foreclosure. Busey follows Federal Housing Finance Agency guidelines on single-family foreclosures and real estate owned evictions on portfolio loans. Loans Evaluated Individually Busey evaluates loans with disparate risk characteristics on an individual basis. The following tables provide details of loans evaluated individually, segregated by loan category and class. The unpaid principal balance represents customer outstanding contractual principal balances excluding any partial charge-offs. Recorded investment represents the amortized cost of customer balances net of any partial charge-offs recognized on the loan. Average recorded investment is calculated using the most recent four quarters (dollars in thousands) : As of March 31, 2024 Unpaid Recorded Investment Average With No With Total Related Loans evaluated individually Commercial loans: C&I and other commercial $ 20,372 $ 2,197 $ 10,920 $ 13,117 $ 7,498 $ 6,553 Commercial real estate — — — — — 2,618 Commercial loans evaluated individually 20,372 2,197 10,920 13,117 7,498 9,171 Retail loans: Retail real estate 213 61 25 86 25 289 Retail loans evaluated individually 213 61 25 86 25 289 Total loans evaluated individually $ 20,585 $ 2,258 $ 10,945 $ 13,203 $ 7,523 $ 9,460 As of December 31, 2023 Unpaid Recorded Investment Average With No With Total Related Loans evaluated individually Commercial loans: C&I and other commercial $ 7,283 $ 585 $ 1,785 $ 2,370 $ 785 $ 5,244 Commercial real estate 2,600 610 85 695 85 3,865 Real estate construction — — — — — 49 Commercial loans evaluated individually 9,883 1,195 1,870 3,065 870 9,158 Retail loans: Retail real estate 213 61 25 86 25 790 Retail loans evaluated individually 213 61 25 86 25 790 Total loans evaluated individually $ 10,096 $ 1,256 $ 1,895 $ 3,151 $ 895 $ 9,948 Allowance for Credit Losses The ACL is a valuation account that is deducted from the portfolio loans’ amortized cost bases to present the net amount expected to be collected on the portfolio loans. Portfolio loans are charged off against the ACL when management believes the uncollectibility of a loan balance is confirmed. Recoveries will be recognized up to the aggregate amount of previously charged-off balances. The ACL is established through the provision for credit loss charged to income. Management estimates the ACL 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. The cumulative loss rate used as the basis for the estimate of credit losses is comprised of Busey’s historical loss experience beginning in 2010. Due to the continued economic uncertainty in the markets in which the Company operates, Busey will continue to utilize a forecast period of 12 months with an immediate reversion to historical loss rates beyond this forecast period in its ACL estimate. The following tables summarize activity in the ACL attributable to each loan class. Allocation of a portion of the ACL to one loan class does not preclude its availability to absorb losses in other loan classes (dollars in thousands) : Three Months Ended March 31, 2024 C&I and Other Commercial Commercial Real Estate Retail Retail Other Total ACL balance, December 31, 2023 $ 21,256 $ 35,465 $ 5,163 $ 26,298 $ 3,558 $ 91,740 Provision for credit losses 10,125 (1,864) (491) (2,093) (639) 5,038 Charged-off (5,218) (96) — (52) (94) (5,460) Recoveries 44 — 41 128 31 244 ACL balance, March 31, 2024 $ 26,207 $ 33,505 $ 4,713 $ 24,281 $ 2,856 $ 91,562 Three Months Ended March 31, 2023 C&I and Other Commercial Commercial Real Estate Retail Retail Other Total ACL balance, December 31, 2022 $ 23,860 $ 38,299 $ 6,457 $ 18,193 $ 4,799 $ 91,608 Provision for credit losses 695 (3,359) (1,329) 5,948 (1,002) 953 Charged-off (400) (539) — (5) (237) (1,181) Recoveries 121 20 31 119 56 347 ACL balance, March 31, 2023 $ 24,276 $ 34,421 $ 5,159 $ 24,255 $ 3,616 $ 91,727 The following tables present the ACL and amortized cost of portfolio loans by loan category and class (dollars in thousands) : As of March 31, 2024 Portfolio Loans ACL Attributed to Portfolio Loans Collectively Individually Total Collectively Individually Total Portfolio loans and related ACL Commercial loans: C&I and other commercial $ 1,815,594 $ 13,117 $ 1,828,711 $ 18,709 $ 7,498 $ 26,207 Commercial real estate 3,331,670 — 3,331,670 33,505 — 33,505 Real estate construction 445,860 — 445,860 4,713 — 4,713 Commercial loans and related ACL 5,593,124 13,117 5,606,241 56,927 7,498 64,425 Retail loans: Retail real estate 1,708,577 86 1,708,663 24,256 25 24,281 Retail other 273,173 — 273,173 2,856 — 2,856 Retail loans and related ACL 1,981,750 86 1,981,836 27,112 25 27,137 Portfolio loans and related ACL $ 7,574,874 $ 13,203 $ 7,588,077 $ 84,039 $ 7,523 $ 91,562 As of December 31, 2023 Portfolio Loans ACL Attributed to Portfolio Loans Collectively Individually Total Collectively Individually Total Portfolio loans and related ACL Commercial loans: C&I and other commercial $ 1,833,624 $ 2,370 $ 1,835,994 $ 20,471 $ 785 $ 21,256 Commercial real estate 3,336,642 695 3,337,337 35,380 85 35,465 Real estate construction 461,717 — 461,717 5,163 — 5,163 Commercial loans and related ACL 5,631,983 3,065 5,635,048 61,014 870 61,884 Retail loans: Retail real estate 1,720,369 86 1,720,455 26,273 25 26,298 Retail other 295,531 — 295,531 3,558 — 3,558 Retail loans and related ACL 2,015,900 86 2,015,986 29,831 25 29,856 Portfolio loans and related ACL $ 7,647,883 $ 3,151 $ 7,651,034 $ 90,845 $ 895 $ 91,740

LEASES

LEASES	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
LEASES	LEASES Busey as the Lessee Busey has operating leases consisting primarily of equipment leases and real estate leases for banking centers, ATM locations, and office space. The following table summarizes lease-related information and balances Busey reported in its Consolidated Balance Sheets (Unaudited) for the periods presented (dollars in thousands) : As of March 31, December 31, Lease balances Right of use assets $ 10,590 $ 11,027 Lease liabilities 10,896 11,308 Supplemental information Year through which lease terms extend 2037 2037 Weighted average remaining lease term 8.26 years 8.39 years Weighted average discount rate 3.61 % 3.59 % The following table represents lease costs and cash flows related to leases for the periods presented (dollars in thousands) : Three Months Ended March 31, 2024 2023 Lease costs Operating lease costs $ 535 $ 628 Variable lease costs 14 5 Short-term lease costs 13 6 Total lease cost 1 $ 562 $ 639 Cash flows related to leases Cash paid for amounts included in the measurement of lease liabilities: Operating lease cash flows – Fixed payments $ 507 $ 570 Operating lease cash flows – Liability reduction 411 479 Right of use assets obtained during the period in exchange for operating lease liabilities — 4 ___________________________________________ 1. Lease costs are included in net occupancy and equipment expense in the Consolidated Statements of Income (Unaudited). Busey was obligated under noncancelable operating leases for office space and other commitments. Future undiscounted lease payments with initial terms of one year or more, are as follows (dollars in thousands) : As of Rent commitments Remainder of 2024 $ 1,515 2025 1,768 2026 1,443 2027 1,277 2028 1,255 2029 1,278 Thereafter 4,200 Total undiscounted cash flows 12,736 Less: Amounts representing interest 1,840 Present value of net future minimum lease payments $ 10,896 Busey as the Lessor Busey occasionally leases parking lots and office space to outside parties. Revenues recorded in connection with these leases, reported in Other income on our Consolidated Statements of Income (Unaudited), are summarized as follows (dollars in thousands) : Three Months Ended March 31, 2024 2023 Rental income $ 202 $ 191

DEPOSITS

DEPOSITS	3 Months Ended
	Mar. 31, 2024
Deposits [Abstract]
DEPOSITS	DEPOSITS The composition of Busey’s deposits is as follows (dollars in thousands) : As of March 31, December 31, Deposits Noninterest-bearing demand deposits $ 2,784,338 $ 2,834,655 Interest-bearing transaction deposits 2,397,937 2,717,139 Saving deposits and money market deposits 3,200,738 2,920,088 Time deposits 1,577,178 1,819,274 Total deposits $ 9,960,191 $ 10,291,156 Additional information about Busey’s deposits follows (dollars in thousands) : As of March 31, December 31, Brokered savings deposits and money market deposits $ 6,001 $ 6,001 Brokered time deposits — 285 Aggregate amount of time deposits with a minimum denomination of $100,000 898,433 1,072,189 Aggregate amount of time deposits with a minimum denomination that meets or exceeds the FDIC insurance limit of $250,000 326,794 386,286 Scheduled maturities of time deposits are as follows (dollars in thousands) : As of Time deposits by schedule of maturities Remainder of 2024 $ 1,371,431 2025 156,304 2026 22,905 2027 13,209 2028 10,150 2029 2,743 Thereafter 436 Time deposits $ 1,577,178

BORROWINGS

BORROWINGS	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
BORROWINGS	BORROWINGS Securities Sold Under Agreements to Repurchase Securities sold under agreements to repurchase, which are classified as secured borrowings, generally mature daily. Securities sold under agreements to repurchase are reflected at the amount of cash received in connection with the transaction. The underlying securities are held by Busey’s safekeeping agent. Busey may be required to provide additional collateral based on fluctuations in the fair value of the underlying securities. Securities sold under agreements to repurchase were as follows (dollars in thousands) : As of March 31, December 31, Securities sold under agreements to repurchase $ 147,175 $ 187,396 Weighted average rate for securities sold under agreements to repurchase 2.96 % 3.26 % Term Loan On May 28, 2021, Busey entered into a Second Amended and Restated Credit Agreement, pursuant to which Busey has access to (1) a $40.0 million revolving line of credit with an initial termination date of April 30, 2022, and (2) a $60.0 million Term Loan with a maturity date of May 31, 2026. The loans had an annual interest rate of 1.75% plus the one-month LIBOR rate. On April 30, 2022, the agreement was amended, effecting an extension of the termination date for the revolving line of credit to April 30, 2023, and providing for the transition from a LIBOR-indexed interest rate to a SOFR-indexed interest rate. Under the terms of the amendment, the loans now have an annual interest rate of 1.80% plus the one-month forward-looking term rate based on SOFR. The agreement has subsequently been amended twice to extend the termination date for the revolving line of credit, which is currently April 30, 2025. During the first quarter of 2024, Busey paid the full $30.0 million balance remaining on the Term Loan, at which time the Term Loan carried interest at a rate of 7.13%. As of March 31, 2024, there was no balance outstanding on the revolving credit facility. The revolving credit facility incurs a non-usage fee based on any undrawn amounts. Short-term Borrowings Busey’s short-term borrowings include loans maturing within one year of the loan origination date and, when applicable, the current portion of long-term debt that is due within 12 months. Short-term borrowings are summarized as follows (dollars in thousands) : As of March 31, December 31, Short-term borrowings Term Loan, current portion due within 12 months $ — $ 12,000 Total short-term debt $ — $ 12,000 Federal funds purchased are short-term borrowings that generally mature between one day and 90 days. During the first quarter of 2024, Busey purchased federal funds to test operational availability to access funds if needed. Busey had no federal funds purchased as of March 31, 2024, or December 31, 2023. Long-term Debt Busey’s long-term debt consists of loans maturing more than one year from the loan origination date, excluding the current portion that is due within 12 months. Long-term debt is summarized as follows (dollars in thousands) : As of March 31, December 31, Long-term debt Term Loan $ — $ 18,000 Total long-term debt $ — $ 18,000 Subordinated Notes On June 1, 2020, Busey issued $125.0 million of fixed-to-floating rate subordinated notes that mature on June 1, 2030. The subordinated notes, which qualify as Tier 2 capital for regulatory purposes, bear interest at an annual rate of 5.25% for the first five years after issuance and thereafter bear interest at a floating rate equal to a three-month benchmark rate plus a spread of 5.11%, as calculated on each applicable determination date. Interest on the subordinated notes is payable semi-annually on each June 1 and December 1 during the five-year fixed-term, and thereafter on March 1, June 1, September 1, and December 1 of each year, commencing on September 1, 2025. The subordinated notes have an optional redemption, in whole or in part, on any interest payment date on or after June 1, 2025. The subordinated notes are unsecured obligations of the Company. On June 2, 2022, Busey issued $100.0 million aggregate principal amount of 5.000% fixed-to-floating rate subordinated notes maturing June 15, 2032, which qualify as Tier 2 capital for regulatory purposes. The price to the public for the subordinated notes was 100% of the principal amount of the subordinated notes. Interest on the subordinated notes accrues at a rate equal to (i) 5.000% per annum from the original issue date to, but excluding, June 15, 2027, payable semiannually in arrears, and (ii) a floating rate per annum equal to a benchmark rate, which is expected to be the Three-Month Term SOFR (as defined in the subordinated notes), plus a spread of 252 basis points from and including June 15, 2027, payable quarterly in arrears. The subordinated notes have an optional redemption, in whole or in part, on any interest payment date on or after June 15, 2027. Unamortized debt issuance costs related to Busey’s subordinated notes are presented in the following table (dollars in thousands) : As of March 31, December 31, Unamortized debt issuance costs Subordinated notes issued in 2020 $ 610 $ 735 Subordinated notes issued in 2022 1,290 1,383 Total unamortized debt issuance costs $ 1,900 $ 2,118

REGULATORY CAPITAL

REGULATORY CAPITAL	3 Months Ended
	Mar. 31, 2024
Banking and Thrift, Other Disclosure [Abstract]
REGULATORY CAPITAL	REGULATORY CAPITAL Busey and Busey Bank are subject to various regulatory capital requirements administered by federal banking agencies. 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 Busey's consolidated financial statements. Capital amounts and classification also are subject to qualitative judgments by regulators about components, risk weightings, and other factors. Banking regulations identify five capital categories for insured depository institutions: well capitalized, adequately capitalized, undercapitalized, significantly undercapitalized, and critically undercapitalized. As of March 31, 2024, and December 31, 2023, all capital ratios of Busey and Busey Bank exceeded well capitalized levels under the applicable regulatory capital adequacy guidelines. Management believes that no events or changes have occurred subsequent to March 31, 2024, that would change this designation. Current Expected Credit Loss Model On August 26, 2020, the FDIC and other federal banking agencies adopted a final rule which provided banking organizations that adopted CECL during 2020 with the option to delay for two years the estimated impact of CECL on regulatory capital and to phase in the aggregate impact of the deferral on regulatory capital over a subsequent three-year period. Under this final rule, because Busey elected to use the deferral option, the regulatory capital impact of our transition adjustments recorded on January 1, 2020, arising from the adoption of CECL, was deferred for two years. In addition, 25 percent of the ongoing impact of CECL on our ACL, retained earnings, and average total consolidated assets from January 1, 2020, through the end of the two-year deferral period, each as reported for regulatory capital purposes, has been added to the deferred transition amounts (“adjusted transition amounts”) and deferred for the two-year period. On January 1, 2022, at the conclusion of the two-year period, the adjusted transition amounts began to be phased-in for regulatory capital purposes at a rate of 25 percent per year, with the phased-in amounts included in regulatory capital at the beginning of each year. Capital Amounts and Ratios The following tables summarize regulatory capital requirements applicable to Busey and Busey Bank (dollars in thousands) : As of March 31, 2024 Actual Minimum Minimum Amount Ratio Amount Ratio Amount Ratio Common equity Tier 1 capital to risk weighted assets First Busey $ 1,166,919 13.45 % $ 390,433 4.50 % $ 563,958 6.50 % Busey Bank $ 1,365,033 15.79 % $ 389,113 4.50 % $ 562,052 6.50 % Tier 1 capital to risk weighted assets First Busey $ 1,240,919 14.30 % $ 520,577 6.00 % $ 694,103 8.00 % Busey Bank $ 1,365,033 15.79 % $ 518,817 6.00 % $ 691,756 8.00 % Total capital to risk weighted assets First Busey $ 1,557,137 17.95 % $ 694,103 8.00 % $ 867,628 10.00 % Busey Bank $ 1,456,250 16.84 % $ 691,756 8.00 % $ 864,695 10.00 % Leverage ratio of Tier 1 capital to average assets First Busey $ 1,240,919 10.46 % $ 474,678 4.00 % N/A N/A Busey Bank $ 1,365,033 11.53 % $ 473,422 4.00 % $ 591,777 5.00 % As of December 31, 2023 Actual Minimum Minimum Amount Ratio Amount Ratio Amount Ratio Common equity Tier 1 capital to risk weighted assets First Busey $ 1,155,973 13.09 % $ 397,331 4.50 % $ 573,923 6.50 % Busey Bank $ 1,362,962 15.48 % $ 396,128 4.50 % $ 572,185 6.50 % Tier 1 capital to risk weighted assets First Busey $ 1,229,973 13.93 % $ 529,775 6.00 % $ 706,367 8.00 % Busey Bank $ 1,362,962 15.48 % $ 528,171 6.00 % $ 704,228 8.00 % Total capital to risk weighted assets First Busey $ 1,540,318 17.44 % $ 706,367 8.00 % $ 882,958 10.00 % Busey Bank $ 1,448,307 16.45 % $ 704,228 8.00 % $ 880,285 10.00 % Leverage ratio of Tier 1 capital to average assets First Busey $ 1,229,973 10.08 % $ 488,315 4.00 % N/A N/A Busey Bank $ 1,362,962 11.19 % $ 487,103 4.00 % $ 608,879 5.00 % Capital Conservation Buffer In July 2013, U.S. federal banking authorities approved the Basel III Rule for strengthening international capital standards. The Basel III Rule introduced a capital conservation buffer, composed entirely of common equity Tier 1 capital, which is added to the minimum risk-weighted asset ratios. The capital conservation buffer is not a minimum capital requirement; however, banking institutions with a ratio of common equity Tier 1 capital to risk-weighted assets below the capital conservation buffer will face constraints on dividends, equity repurchases, and discretionary bonus payments based on the amount of the shortfall. In order to refrain from restrictions on dividends, equity repurchases, and discretionary bonus payments, banking institutions must maintain minimum ratios of (1) common equity Tier 1 capital to risk-weighted assets of at least 7.0%, (2) Tier 1 capital to risk-weighted assets of at least 8.5%, and (3) total capital to risk-weighted assets of at least 10.5%.

TAX CREDIT AND OTHER INVESTMENT

TAX CREDIT AND OTHER INVESTMENTS IN UNCONSOLIDATED ENTITIES	3 Months Ended
	Mar. 31, 2024
Investments, All Other Investments [Abstract]
TAX CREDIT AND OTHER INVESTMENTS IN UNCONSOLIDATED ENTITIES	TAX CREDIT AND OTHER INVESTMENTS IN UNCONSOLIDATED ENTITIES Busey has invested in certain tax-advantaged projects promoting affordable housing, new markets, and historic rehabilitation. These investments are designed to generate returns primarily though the realization of federal and state income tax credits and other tax benefits, such as tax deductions from operating losses of the investments, over specified time periods. These investments are considered to be variable interest entities, and are accounted for under the equity, deferral, or proportional amortization practical expedient methods, as appropriate. Busey is not required to consolidate variable interest entities in which it has concluded it does not have a controlling financial interest, and is not the primary beneficiary. Busey’s maximum exposure to loss related to its investments in these unconsolidated variable interest entities is limited to the carrying amount of the investment, net of any unfunded capital commitments and previously recorded tax credits which remain subject to recapture by taxing authorities based on compliance features required to be met at the project level. Busey believes potential losses from these investments are remote. In addition, Busey has private equity investments, which are primarily in funds that invest in small businesses across diverse sectors including, but not limited to, financial technology, business services, manufacturing, agribusiness, healthcare, software as a service, and environmental, or supporting the preservation of affordable housing. Busey’s investments in these unconsolidated entities and related unfunded investment obligations are reflected in other assets and other liabilities on the Consolidated Balance Sheets (Unaudited), and are summarized in the table below for the periods indicated (dollars in thousands) : As of Location March 31, December 31, Investments in unconsolidated entities Funded investments Other assets $ 64,516 $ 68,516 Unfunded investments Other assets 56,362 58,552 Investments in unconsolidated entities $ 120,878 $ 127,068 Unfunded investment obligations Other liabilities $ 56,362 $ 58,552 Upon adoption of ASU 2023-02 on January 1, 2024, Busey elected to apply the proportional amortization method in accounting for investments in tax-advantaged projects. Income tax credits and other tax benefits, net of investment amortization, were included as a component of our estimated annual effective tax rate used for the calculation of income taxes presented in the Consolidated Statements of Income (Unaudited). These income tax credits and other benefits, along with the investment amortization, are presented in the table below (dollars in thousands) : Three Months Ended March 31, 2024 Tax effects of investments in tax-advantaged projects Income tax credits and other tax benefits $ 4,101 Amortization of investments in tax-advantaged projects 3,647

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION Stock Options Busey has outstanding stock options assumed from acquisitions. A summary of the status of, and changes in, the Company's stock option awards for the three months ended March 31, 2024, follows: Options Shares Weighted- Weighted- Outstanding at December 31, 2023 21,266 $ 23.53 2.88 years Forfeited (880) 23.53 Outstanding at March 31, 2024 20,386 23.53 2.63 years Exercisable at March 31, 2024 20,386 23.53 2.63 years 2020 Equity Plan The 2020 Equity Plan was originally approved by stockholders at the 2020 Annual Meeting of Stockholders. A description of the 2020 Equity Plan, as originally approved, can be found in Appendix A within Busey’s Proxy Statement for the 2020 Annual Meeting of Stockholders filed on April 9, 2020 . An amendment and restatement of the 2020 Equity Plan was approved by stockholders at the 2023 Annual Meeting of Stockholders. Terms of the amended and restated 2020 Equity Plan are substantially identical to those of the originally approved 2020 Equity Plan, other than a 1,350,000 increase in the number of shares authorized for issuance under the plan. More information can be found in Appendix A within Busey’s Proxy Statement for the 2023 Annual Meeting of Stockholders filed on April 14, 2023 . Busey has granted RSU, PSU, and DSU awards under the terms of the 2020 Equity Plan. Upon vesting and delivery, shares are expected, though not required, to be issued from treasury stock. There were 1,333,769 shares available for issuance under the 2020 Equity Plan as of March 31, 2024. A description of RSU, PSU, and DSU awards granted in 2024 under the terms of the 2020 Equity Plan is provided below. Further information related to awards granted in prior years has been presented in the Annual Reports previously filed with the SEC corresponding to the year of each award grant. RSU Awards Busey grants RSU awards to members of management periodically throughout the year. RSU awards are stock-based awards for which vesting is conditional upon meeting established service criteria. Each RSU is equivalent to one share of Busey’s common stock. Busey’s RSUs have requisite service periods ranging from one year to five years, and are subject to accelerated vesting upon eligible retirement from Busey. Recipients earn quarterly dividend equivalents on their respective RSUs, which entitle the recipients to additional units. Therefore, dividends earned each quarter compound based upon the updated unit balances. On March 20, 2024, under the terms of the 2020 Equity Plan, Busey granted 189,179 RSUs to members of management. The grant date fair value of the award was $4.4 million, which will be recognized as compensation expense over the requisite service period ranging from one year to five years. The terms of these awards included an accelerated vesting provision upon eligible retirement from Busey, after a one-year minimum requisite service period. Subsequent to the requisite service period, the awards will become 100% vested. A summary of changes in Busey’s RSU awards for the three months ended March 31, 2024, is as follows: RSU Awards Shares Weighted- Nonvested at December 31, 2023 1,041,444 $ 22.05 Granted 189,179 23.35 Dividend equivalents earned 10,219 24.46 Vested (7,681) 23.23 Forfeited (5,347) 23.38 Nonvested at March 31, 2024 1,227,814 22.25 PSU Awards Busey grants PSU awards to members of management periodically throughout the year. PSU awards are stock-based awards for which vesting is conditional upon meeting established performance criteria. Each PSU is equivalent to one share of Busey’s common stock. The number of PSUs that ultimately vest will be determined based on the extent to which market or other performance goals are achieved. Busey’s PSUs are subject to accelerated service-based vesting conditions upon eligible retirement from Busey. After performance determination, dividend equivalents are compounded based upon the updated PSU balances at each dividend date during the performance period. On March 20, 2024, under the terms of the 2020 Equity Plan, Busey granted a target of 94,604 PSUs with a maximum award of 151,366 units. The actual number of units issued at the vesting date could range from 0% to 160% of the initial grant, depending on attaining a market-based total stockholder return performance goal. The estimated grant date fair value of the award was $2.2 million, which will be recognized in compensation expense over the performance period ending December 31, 2026. Busey expects to finalize the grant date fair value of these awards in the second quarter of 2024. On March 20, 2024, under the terms of the 2020 Equity Plan, Busey granted a target of 94,604 PSUs with a maximum award of 151,366 units. The actual number of units issued at the vesting date could range from 0% to 160% of the initial grant, depending on attaining an adjusted return on average tangible common equity performance goal. The grant date fair value of the award was $2.2 million, which will be recognized in compensation expense over the performance period ending December 31, 2026. The actual amount of compensation expense recognized for these awards may vary, subject to achievement of the performance goal. A summary of changes in Busey’s PSU awards for the three months ended March 31, 2024, is as follows: PSU Awards Shares 1 Weighted- Nonvested at December 31, 2023 341,700 $ 22.67 Granted 189,208 23.35 Dividend equivalents earned 2 4,264 22.95 Vested 2 (4,264) 22.95 Forfeited (1,754) 22.76 Nonvested at March 31, 2024 529,154 $ 22.91 ___________________________________________ 1. Shares for PSU awards represent target shares at the grant date. 2. PSUs granted in 2021 vested on December 31, 2023, with performance determination and settlement activity in the first quarter of 2024. Final performance was determined to be at 50% of target. DSU Awards Busey grants DSU awards to its directors and advisory directors. DSU awards are stock-based awards with a deferred settlement date. Each DSU is equivalent to one share of Busey’s common stock. DSUs vest over a one-year period following the grant date. Under the 2020 Equity Plan, DSUs are generally subject to the same terms as RSUs, except that following vesting of DSUs, settlement occurs within 30 days following the earlier of separation from the board or a change in control of the Company. After vesting and prior to delivery, DSUs will continue to earn dividend equivalents. On March 20, 2024, under the terms of the 2020 Equity Plan, Busey granted 35,847 DSUs to directors and advisory directors. The grant date fair value of the award totaled $0.8 million and will be recognized as compensation expense over the requisite service period of one year. Subsequent to the requisite service period, the awards will become 100% vested. A summary of changes in Busey’s DSU awards for the three months ended March 31, 2024, is as follows: DSU Awards Shares Weighted- Nonvested at December 31, 2023 43,026 $ 20.41 Granted 35,847 23.35 Dividend equivalents earned 1,836 24.46 Vested (44,862) 20.57 Nonvested at March 31, 2024 35,847 23.35 Vested and outstanding at March 31, 2024 189,000 22.82 2021 Employee Stock Purchase Plan The First Busey Corporation 2021 ESPP was approved at Busey’s 2021 Annual Meeting of Stockholders and details can be found in Appendix A within Busey’s Definitive Proxy Statement filed with the SEC on April 8, 2021 . The purpose of the 2021 ESPP is to provide a means through which our employees may acquire a proprietary interest in Busey by purchasing shares of our common stock at a 15% discount through voluntary payroll deductions, to assist us in retaining the services of our employees and securing and retaining the services of new employees, and to provide incentives for our employees to exert maximum efforts toward our success. The 2021 ESPP initially reserved for issuance and purchase an aggregate of 600,000 shares of Busey’s common stock. The first offering under the 2021 ESPP began on July 1, 2021. There were 429,074 shares available for issuance under the 2021 ESPP as of March 31, 2024. Stock-based Compensation Expense Busey did not record any stock option compensation expense for the three months ended March 31, 2024, or 2023. Busey did not have any unrecognized stock option compensation expense as of March 31, 2024. Busey recognized compensation expense related to nonvested RSU, PSU, and DSU awards, as well as the 2021 ESPP, as summarized in the table below (dollars in thousands) : Three Months Ended March 31, 2024 2023 Stock-based compensation expense RSU awards $ 894 $ 1,020 PSU awards 1 1,210 360 DSU awards 215 196 2021 ESPP 84 93 Total stock-based compensation expense $ 2,403 $ 1,669 ___________________________________________ 1. Expense for PSU awards with a market-based total stockholder return performance goal represents amounts based on target shares at the grant date. Expense for PSU awards with return on average tangible common equity and compounded annual revenue growth rate performance goals represents amounts based on target shares at the grant date, adjusted for performance expectations as of the date indicated. Unamortized compensation expense related to nonvested RSU, PSU, and DSU awards is summarized in the table below (dollars in thousands) : As of March 31, December 31, Unamortized stock-based compensation RSU awards $ 10,259 $ 6,842 PSU awards 1 8,743 3,607 DSU awards 812 190 Total unamortized stock-based compensation $ 19,814 $ 10,639 Weighted average period over which expense is to be recognized 2.7 years 2.4 years ___________________________________________ 1. Unamortized expense for PSU awards with a market-based total stockholder return performance goal represents amounts based on target shares at grant date. Unamortized expense for PSU awards with return on average tangible common equity and compounded annual revenue growth rate performance goals represents amounts based on target shares at grant date, adjusted for performance expectations as of the date indicated.

OUTSTANDING COMMITMENTS AND CON

OUTSTANDING COMMITMENTS AND CONTINGENT LIABILITIES	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
OUTSTANDING COMMITMENTS AND CONTINGENT LIABILITIES	OUTSTANDING COMMITMENTS AND CONTINGENT LIABILITIES Legal Matters Busey is a party to legal actions which arise in the normal course of its business activities. Legal and administrative proceedings are subject to inherent uncertainties, and while unfavorable outcomes could occur, Busey does not believe at this time that any potential liabilities relating to pending or potential legal matters are likely to have a material impact on Busey's results of operations or financial position. Credit Commitments and Contingencies A summary of the contractual amount of Busey’s exposure to off-balance-sheet risk relating to the Company’s commitments to extend credit and standby letters of credit follows (dollars in thousands) : As of March 31, December 31, Financial instruments whose contract amounts represent credit risk Commitments to extend credit $ 2,118,621 $ 2,132,500 Standby letters of credit 46,967 43,996 Total commitments $ 2,165,588 $ 2,176,496 Franchise Tax Matter In 2021, Busey received an inquiry from the Illinois Secretary of State (“ISOS”), pursuant to which the ISOS asked for additional information regarding certain of our franchise tax filings and the calculation of amounts due thereunder. The franchise tax is established by the Illinois Business Corporation Act (“BCA”) 805 ILCS 5/1 et seq., and is a tax imposed on foreign and domestic corporations for the privilege of conducting business in Illinois. Busey has been cooperating with the inquiry and has agreed to prepare additional BCA forms requested by the ISOS, with a full reservation of rights by Busey, including seeking judicial relief, if necessary, with respect to any potential dispute regarding Busey’s preparation of the BCA forms and the calculation of the franchise taxes due. Where a loss is believed to be reasonably possible, but not probable, or the loss cannot be reasonably estimated, as is the case with this matter, no accrual is required. It is reasonably possible that this matter could require us to pay additional taxes, including potential penalties and interest, or make other expenditures or accrue liabilities in amounts that could not be reasonably estimated as of March 31, 2024. If the likelihood of potential liabilities elevates, requiring an accrual, the potential future liabilities could be material in the period(s) in which they are recorded.

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	DERIVATIVE FINANCIAL INSTRUMENTS Busey utilizes interest rate swap agreements as part of its asset liability management strategy to help manage its interest rate risk position. Additionally, Busey enters into derivative financial instruments, including interest rate lock commitments issued to residential loan customers for loans that will be held for sale; forward sales commitments to sell residential mortgage loans to investors; and interest rate swaps, risk participation agreements, and foreign currency exchange contracts with customers and other third parties. See “ Note 12: Fair Value Measurements ” for further discussion of the fair value measurement of such derivatives. To secure its obligations under derivative contracts, Busey pledged cash and held collateral as follows (dollars in thousands) : As of March 31, December 31, Cash pledged to secure obligations under derivative contracts $ 34,210 $ 34,210 Collateral held to secure obligations under derivative contracts 24,860 19,280 Derivative Instruments Designated as Hedges Busey entered into derivative instruments designated as cash flow hedges. For a derivative instrument that is designated and qualifies as a cash flow hedge, the change in fair value of the derivative instrument is reported as a component of OCI and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Changes in fair value of components excluded from the assessment of effectiveness are recognized in current earnings. Interest Rate Swaps Designated as Cash Flow Hedges Interest rate swaps with notional amounts totaling $450.0 million as of March 31, 2024, and $350.0 million as of December 31, 2023, were designated as cash flow hedges. Busey entered into one $50.0 million interest rate swap to hedge the risks of variability in cash flows for future interest payments attributable to changes in the 3-month CME Term SOFR benchmark interest rate on Busey’s junior subordinated debt owed to unconsolidated trusts (Debt Swap). In addition, Busey entered into one $300.0 million receive fixed pay floating interest rate swap to reduce Busey’s asset sensitivity (Prime Loan Swap). Duration was added to our loan portfolio by fixing a portion of floating prime-based loans. Interest rates had risen above their historical lows allowing Busey to lock in a portion of its loan portfolio to reduce asset sensitivity while creating a more stable margin in a volatile rate market. These hedges were determined to be highly effective during the period, and Busey expects its hedges to remain highly effective during the remaining terms of the swaps. Further, in 2024 Busey entered into one $100.0 million one year forward-starting SOFR-based receive-fixed pay-floating interest rate swap, with an effective date of March 5, 2025, to reduce Busey’s asset sensitivity (SOFR Loan Swap). Changes in fair value were recorded net of tax in OCI. A summary of the interest-rate swaps designated as cash flow hedges is presented below (dollars in thousands) : As of Location March 31, December 31, Debt Swap Notional amount $ 50,000 $ 50,000 Weighted average fixed pay rates 1.79 % 1.79 % Weighted average variable 3-month Fallback Rate (SOFR) receive rates 5.62 % 5.61 % Weighted average maturity 0.46 years 0.71 years Prime Loan Swap Notional amount $ 300,000 $ 300,000 Weighted average fixed receive rates 4.81 % 4.81 % Weighted average variable Prime pay rates 8.50 % 8.50 % Weighted average maturity 4.85 years 5.10 years SOFR Loan Swap Notional amount $ 100,000 $ — Weighted average fixed receive rates 3.72 % — Weighted average maturity 4.93 years — Gross aggregate fair value of the swaps Gross aggregate fair value of swap assets Other assets $ 1,178 $ 1,293 Gross aggregate fair value of swap liabilities Other liabilities 30,303 25,411 Balances carried in AOCI Unrealized gains (losses) on cash flow hedges, net of tax AOCI $ (20,272) $ (16,694) Busey expects to reclassify unrealized gains and losses from OCI to interest income and interest expense as shown in the following table, during the next 12 months (dollars in thousands) . Amounts actually recognized could differ from these expectations due to changes in interest rates, hedge de-designations, and the addition of other hedges subsequent to March 31, 2024. As of Unrealized gains (losses) in OCI expected to be recognized in income Unrealized losses expected to be reclassified from OCI to interest income $ (952) Unrealized gains expected to be reclassified from OCI to interest expense 483 Net unrealized gains (losses) in OCI expected to be recognized in net interest income $ (469) Interest expense recorded on these swap transactions was as follows for the periods presented (dollars in thousands) : Three Months Ended March 31, 2024 2023 Interest on swap transactions Increase (decrease) in interest income on swap transactions $ (2,796) $ (2,192) (Increase) decrease in interest expense on swap transactions 483 383 Net increase (decrease) in net interest income on swap transactions $ (2,313) $ (1,809) The following table reflects the net gains (losses) relating to cash flow derivative instruments that were recorded in AOCI and the Consolidated Statements of Income (Unaudited) during the periods presented (dollars in thousands) : Three Months Ended March 31, 2024 2023 Unrealized gains (losses) on cash flow hedges Net gain (loss) recognized in OCI, net of tax $ (5,232) $ 3,050 (Gain) loss reclassified from OCI to interest income, net of tax 1,999 1,567 (Gain) loss reclassified from OCI to interest expense, net of tax (345) (274) Net change in unrealized gains (losses) on cash flow hedges, net of tax $ (3,578) $ 4,343 Derivative Instruments Not Designated as Hedges Interest Rate Swaps Not Designated as Hedges Busey may offer derivative contracts to its customers in connection with their risk management needs. Busey manages the risk associated with these contracts by entering into equal and offsetting derivative agreements with third-party dealers. These contracts supported variable rate, commercial loan relationships totaling $678.3 million as of March 31, 2024, and $663.1 million as of December 31, 2023. These derivatives generally worked together as an economic interest rate hedge, but Busey did not designate them for hedge accounting treatment. Consequently, changes in fair value of the corresponding derivative financial asset or liability were recorded as either a charge or credit to current earnings during the period in which the changes occurred. Amounts and fair values of derivative assets and liabilities related to customer interest rate swaps recorded in the Consolidated Balance Sheets (Unaudited) are summarized as follows (dollars in thousands) : As of March 31, 2024 Derivative Asset Derivative Liability Notional Fair Notional Fair Derivatives not designated as hedging instruments Interest rate swaps – pay floating, receive fixed $ 71,472 $ 868 $ 606,862 $ 33,552 Interest rate swaps – pay fixed, receive floating 606,862 33,552 71,472 868 Total derivatives not designated as hedging instruments $ 678,334 $ 34,420 $ 678,334 $ 34,420 As of December 31, 2023 Derivative Asset Derivative Liability Notional Fair Notional Fair Derivatives not designated as hedging instruments Interest rate swaps – pay floating, receive fixed $ 177,883 $ 2,375 $ 485,253 $ 26,289 Interest rate swaps – pay fixed, receive floating 485,253 26,289 177,883 2,375 Total derivatives not designated as hedging instruments $ 663,136 $ 28,664 $ 663,136 $ 28,664 Changes in fair value of these derivative assets and liabilities were recorded in noninterest expense in the Consolidated Statements of Income (Unaudited) and are summarized as follows (dollars in thousands) : Three Months Ended March 31, Location 2024 2023 Interest rate swaps Pay floating, receive fixed Noninterest expense $ 5,480 $ (7,667) Pay fixed, receive floating Noninterest expense (5,480) 7,667 Net change in fair value of interest rate swaps $ — $ — Risk Participation Agreements To manage the credit risk exposure related to customer-facing swaps, Busey entered into risk participation agreements in conjunction with loan participation arrangements with other financial institutions. Under these risk participation agreements, Busey purchased a portion of the credit exposure, paying an up-front fee, and will receive a payment from the counterparty if the loan customer defaults on its obligations. Busey also entered into a risk participation agreement under which Busey sold a portion of its credit exposure, receiving an up-front fee, and will be required to make a payment to the counterparty if the loan customer defaults on its obligations. The notional amount of the risk participation agreements reflect Busey's pro-rata share of the derivative instrument, consistent with its share of the related participated loan. The risk participation agreements mature between June 2024 and January 2029, and are summarized as follows (dollars in thousands) : As of March 31, December 31, Risk participation agreements purchased Number of risk participation agreements 4 3 Notional amount $ 35,097 $ 34,251 Fair value 9 15 Risk participation agreements sold Number of risk participation agreements 1 1 Notional amount $ 20,001 20,001 Fair value — — Mortgage Banking Derivatives Interest Rate Lock Commitments Interest rate lock commitments that meet the definition of derivative financial instruments under ASC Topic 815 “Derivatives and Hedging” are carried at their fair values in other assets or other liabilities in the Consolidated Balance Sheets (Unaudited), with changes in the fair values of the corresponding derivative financial assets or liabilities recorded as either a charge or credit to current earnings during the period in which the changes occurred. Forward Sales Commitments Busey economically hedges mortgage loans held for sale and interest rate lock commitments issued to its residential loan customers related to loans that will be held for sale by obtaining corresponding forward sales commitments with an investor to sell the loans at an agreed-upon price at the time the interest rate locks are issued to the customers. Forward sales commitments that meet the definition of derivative financial instruments under ASC Topic 815 “Derivatives and Hedging” are carried at their fair values in other assets or other liabilities in the Consolidated Balance Sheets (Unaudited). While such forward sales commitments generally served as an economic hedge to mortgage loans held for sale and interest rate lock commitments, Busey did not designate them for hedge accounting treatment. Changes in fair value of the corresponding derivative financial asset or liability were recorded as either a charge or credit to current earnings during the period in which the changes occurred. Amounts and fair values of mortgage banking derivatives included in the Consolidated Balance Sheets (Unaudited) are summarized as follows (dollars in thousands) : As of March 31, 2024 As of December 31, 2023 Location Notional Fair Notional Fair Mortgage banking derivative assets Interest rate lock commitments Other assets $ 9,123 $ 133 $ 3,477 $ 25 Forward sales commitments Other assets 2,772 9 1,761 11 Mortgage banking derivative assets $ 11,895 $ 142 $ 5,238 $ 36 Mortgage banking derivative liabilities Interest rate lock commitments Other liabilities $ 268 $ 3 $ 1,615 $ 10 Forward sales commitments Other liabilities 6,619 51 5,216 47 Mortgage banking derivative liabilities $ 6,887 $ 54 $ 6,831 $ 57 Gains (losses) relating to these derivative instruments are summarized as follows for the periods presented (dollars in thousands) : Three Months Ended March 31, Location 2024 2023 Gains (losses) Interest rate lock commitments Mortgage revenue $ 267 $ 37 Forward sales commitments Mortgage revenue 9 (54) Interest rate lock commitments Other expense 5 — Forward sales commitments Other expense 51 —

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The fair value of an asset or liability is the price that would be received by selling that asset or paid in transferring that liability (exit price) in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. ASC Topic 820 “Fair Value Measurement” establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs —Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2 Inputs —Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. • Level 3 Inputs —Unobservable inputs for determining the fair values of assets or liabilities that reflect the Company’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. These valuation methodologies were applied to Busey’s assets and liabilities that are carried at fair value. In general, fair value is based upon quoted market prices, when available. If such quoted market prices are not available, fair values are measured utilizing independent valuation techniques of identical or similar securities for which significant assumptions are derived primarily from or corroborated by observable data. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect, among other things, counterparty credit quality and the company's creditworthiness as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. While management believes Busey's valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis Debt Securities Available for Sale Debt securities classified as available for sale are reported at fair value utilizing Level 2 inputs. Busey obtains fair value measurements from an independent pricing service. The independent pricing service utilizes evaluated pricing models that vary by asset class and incorporate available trade, bid, and other market information. Because many fixed income securities do not trade on a daily basis, the independent pricing service applies available information to prepare evaluations, with a focus on observable market data such as benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing. The independent pricing service uses model processes, such as the Option Adjusted Spread model, to assess interest rate impact and develop prepayment scenarios. Models and processes take into account market conventions. For each asset class, a team of evaluators gathers information from market sources and integrates relevant credit information, perceived market movements, and sector news into the evaluated pricing applications and models. Market inputs that the independent pricing service normally seeks for evaluations of securities, listed in approximate order of priority, include: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data including market research publications. The independent pricing service also monitors market indicators, industry, and economic events. For certain security types, additional inputs may be used or some of the market inputs may not be applicable. Evaluators may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs listed are available for use in the evaluation process for each security evaluation on a given day. Because the data utilized was observable, the securities have been classified as Level 2. Equity Securities Equity securities are reported at fair value utilizing Level 1 or Level 2 inputs. Fair value measurements of mutual funds, when held, are determined using unadjusted quoted prices in active markets for identical assets at the measurement date and are classified as Level 1. Fair value measurements of stock utilize quoted prices for identical or similar assets in markets that are not active and are classified as Level 2. Derivative Assets and Derivative Liabilities Busey’s derivative assets and derivative liabilities are reported at fair value utilizing Level 2 or Level 3 inputs. Fair values of derivative assets and liabilities are determined based on prices that are obtained from a third-party which uses observable market inputs and, with the exception of our risk participation agreements, are classified as Level 2. Due to the significance of unobservable inputs, derivative assets related to our risk participation agreements are classified as Level 3. The following tables summarize financial assets and financial liabilities measured at fair value on a recurring basis as of March 31, 2024, and December 31, 2023, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) : As of March 31, 2024 Level 1 Level 2 Level 3 Total Debt securities available for sale: U.S. Treasury securities $ — $ 742 $ — $ 742 Obligations of U.S. government corporations and agencies — 5,743 — 5,743 Obligations of states and political subdivisions — 150,926 — 150,926 Asset-backed securities — 461,698 — 461,698 Commercial mortgage-backed securities — 92,563 — 92,563 Residential mortgage-backed securities — 1,021,733 — 1,021,733 Corporate debt securities — 164,667 — 164,667 Equity securities — 9,790 — 9,790 Derivative assets — 35,740 9 35,749 Derivative liabilities — 64,777 — 64,777 As of December 31, 2023 Level 1 Level 2 Level 3 Total Debt securities available for sale: U.S. Treasury securities $ — $ 15,946 $ — $ 15,946 Obligations of U.S. government corporations and agencies — 5,832 — 5,832 Obligations of states and political subdivisions — 172,845 — 172,845 Asset-backed securities — 468,223 — 468,223 Commercial mortgage-backed securities — 103,509 — 103,509 Residential mortgage-backed securities — 1,111,312 — 1,111,312 Corporate debt securities — 209,904 — 209,904 Equity securities 448 9,364 — 9,812 Derivative assets — 29,993 15 30,008 Derivative liabilities — 54,132 — 54,132 Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Certain financial assets and financial liabilities are measured at fair value on a non-recurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Loans Evaluated Individually Busey does not record portfolio loans at fair value on a recurring basis. However, periodically, a loan is evaluated individually and is reported at the fair value of the underlying collateral, less estimated costs to sell, if repayment is expected solely from the collateral. If the collateral value is not sufficient, a specific reserve is recorded. Collateral values are estimated using a combination of observable inputs, including recent appraisals, and unobservable inputs based on customized discounting criteria. Due to the significance of unobservable inputs, fair values of individually evaluated collateral dependent loans have been classified as Level 3. Bank Property Held for Sale Bank property held for sale represents certain banking center office buildings which Busey has closed and consolidated with other existing banking centers. Bank property held for sale is measured at the lower of amortized cost or fair value less estimated costs to sell. Fair values were based upon discounted appraisals or real estate listing prices. Due to the significance of unobservable inputs, fair values of all bank property held for sale have been classified as Level 3. The following tables summarize assets and liabilities measured at fair value on a non-recurring basis for the periods presented, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) : As of March 31, 2024 Level 1 Level 2 Level 3 Total Loans evaluated individually, net of related allowance $ — $ — $ 3,422 $ 3,422 Bank property held for sale with impairment — — 4,238 4,238 As of December 31, 2023 Level 1 Level 2 Level 3 Total Loans evaluated individually, net of related allowance $ — $ — $ 1,000 $ 1,000 Bank property held for sale with impairment — — 4,286 4,286 The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis for which the Company has utilized Level 3 inputs to determine fair value (dollars in thousands) : As of March 31, 2024 Fair Value Valuation Unobservable Range Loans evaluated individually, net of related allowance $ 3,422 Appraisal of collateral Appraisal adjustments -25.0% to -100.0% (-68.7)% Bank property held for sale with impairment 4,238 Appraisal of collateral or real estate listing price Appraisal adjustments -9.0% to -64.9% (-39.1)% As of December 31, 2023 Fair Value Valuation Unobservable Range Loans evaluated individually, net of related allowance $ 1,000 Appraisal of collateral Appraisal adjustments -41.2% to -100.0% (-47.2)% Bank property held for sale with impairment 4,286 Appraisal of collateral or real estate listing price Appraisal adjustments -6.2% to -64.9% (-38.4)% Financial Assets and Financial Liabilities That Are Not Carried at Fair Value Estimated fair values of financial instruments that are not carried at fair value in Busey’s Consolidated Balance Sheets (Unaudited), segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows (dollars in thousands) : As of March 31, 2024 As of December 31, 2023 Carrying Fair Carrying Fair Financial assets Level 1 inputs: Cash and cash equivalents $ 591,071 $ 591,071 $ 719,581 $ 719,581 Level 2 inputs: Debt securities held to maturity 862,218 713,031 872,628 730,397 Loans held for sale 6,827 6,834 2,379 2,401 Accrued interest receivable 46,530 46,530 45,288 45,288 Level 3 inputs: Portfolio loans, net 7,496,515 7,293,871 7,559,294 7,276,905 Mortgage servicing rights 989 5,468 3,289 18,079 Other servicing rights 1,573 2,008 1,597 2,062 Financial liabilities Level 2 inputs: Time deposits $ 1,577,178 $ 1,559,643 $ 1,819,274 $ 1,804,905 Securities sold under agreements to repurchase 147,175 147,175 187,396 187,396 Short-term borrowings — — 12,000 12,034 Long-term debt — — 18,000 18,020 Junior subordinated debt owed to unconsolidated trusts 72,040 58,776 71,993 57,153 Accrued interest payable 26,707 26,707 28,418 28,418 Level 3 inputs: Subordinated notes, net of unamortized issuance costs 223,100 204,750 222,882 200,000

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE Basic earnings per share is computed by dividing net income for the period by the weighted average number of common shares outstanding, which include DSUs that are vested but not delivered. Diluted earnings per common share is computed using the treasury stock method and reflects the potential dilution that could occur if Busey’s outstanding stock options and warrants were exercised, stock units were vested, and ESPP shares were issued. Earnings per common share have been computed as follows (dollars in thousands, except per share amounts) : Three Months Ended March 31, 2024 2023 Net income $ 26,225 $ 36,786 Weighted average number of common shares outstanding, basic 55,416,589 55,397,989 Dilutive effect of common stock equivalents: Warrants — 1,296 RSU awards 653,437 651,777 PSU awards 293,389 90,645 DSU awards 33,481 24,345 2021 ESPP 9,604 13,554 Weighted average number of common shares outstanding, diluted 56,406,500 56,179,606 Basic earnings per common share $ 0.47 $ 0.66 Diluted earnings per common share $ 0.46 $ 0.65 Average shares that were excluded from the computation of diluted earnings per common share because their effect would have been anti-dilutive are summarized in the table below for the periods presented: Three Months Ended March 31, 2024 2023 Anti-dilutive common stock equivalents Options 20,386 22,806 PSU awards 108,671 265,459 Total anti-dilutive common stock equivalents 129,057 288,265

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2024
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Alternative [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The following tables present changes in AOCI by component, net of tax, for the periods indicated (dollars in thousands) : Three Months Ended March 31, 2024 2023 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Unrealized/Unrecognized gains (losses) on debt securities Balance at beginning of period $ (282,688) $ 80,579 $ (202,109) $ (352,878) $ 100,585 $ (252,293) Unrealized holding gains (losses) on debt securities available for sale, net (7,947) 2,266 (5,681) 30,693 (8,749) 21,944 Amounts reclassified from AOCI, net 6,802 (1,939) 4,863 (4) 1 (3) Amortization of unrecognized losses on securities transferred to held to maturity 1,411 (402) 1,009 1,693 (483) 1,210 Balance at end of period (282,422) 80,504 (201,918) (320,496) 91,354 (229,142) Unrealized gains (losses) on cash flow hedges Balance at beginning of period (23,348) 6,654 (16,694) (29,350) 8,365 (20,985) Unrealized holding gains (losses) on cash flow hedges, net (7,318) 2,086 (5,232) 4,264 (1,214) 3,050 Amounts reclassified from AOCI, net 2,313 (659) 1,654 1,809 (516) 1,293 Balance at end of period (28,353) 8,081 (20,272) (23,277) 6,635 (16,642) Total AOCI $ (310,775) $ 88,585 $ (222,190) $ (343,773) $ 97,989 $ (245,784)

OPERATING SEGMENTS AND RELATED

OPERATING SEGMENTS AND RELATED INFORMATION	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
OPERATING SEGMENTS AND RELATED INFORMATION	OPERATING SEGMENTS AND RELATED INFORMATION Busey has three reportable operating segments: Banking, Wealth Management, and FirsTech. Busey’s three operating segments are strategic business units that are separately managed, as they offer different products and services and have different marketing strategies. The Banking Operating Segment The Banking operating segment provides a full range of banking services to individual and corporate customers through First Busey Corporation’s wholly-owned bank subsidiary, Busey Bank, with 58 banking centers in Illinois; the St. Louis, Missouri, metropolitan area; southwest Florida; and Indianapolis, Indiana. Banking services offered to individual customers include customary types of demand and savings deposits, money transfers, safe deposit services, individual retirement accounts and other fiduciary services, automated teller machines, and technology-based networks, as well as a variety of loan products including residential real estate, home equity lines of credit, and consumer loans. Banking services offered to corporate customers include commercial, commercial real estate, real estate construction, and agricultural loans, as well as commercial depository services such as cash management. The Wealth Management Operating Segment The Wealth Management operating segment provides a full range of asset management, investment, brokerage, fiduciary, philanthropic advisory, tax preparation, and farm management services to individuals, businesses, and foundations. Services are provided through Busey Capital Management, Inc., a wholly-owned subsidiary of Busey Bank, and Busey Wealth Management, a division of Busey Bank. Wealth management services tailored to individuals include trust and estate advisory services and financial planning. Business services include business succession planning and employee retirement plan services. Services for foundations include investment strategy consulting and fiduciary services. The FirsTech Operating Segment The FirsTech operating segment provides comprehensive and innovative payment technology solutions through Busey Bank’s wholly-owned subsidiary, FirsTech. FirsTech's multi-channel payment platform allows businesses to collect payments from their customers in a variety of ways to enable fast, frictionless payments. Payment method vehicles include, but are not limited to, text-based mobile bill pay; interactive voice response; electronic payment concentration delivered to Automated Clearing House networks, money management, and credit card networks; walk-in payment processing for customers at retail pay agents; customer service payments made over a telephone; direct debit services; and lockbox remittance processing for customers to make payments by mail. FirsTech also provides additional tools to help clients with billing, reconciliation, bill reminders, and treasury services. FirsTech's client base represents a diverse set of industries, with a higher concentration in highly regulated industries, such as financial institutions, utility, insurance, and telecommunications industries. Segment Financial Information The segment financial information provided below has been derived from information used by management to monitor and manage Busey’s financial performance. The accounting policies of the three operating segments are the same as those described in the summary of significant accounting policies in “ Note 1. Significant Accounting Policies ” of Busey’s 2023 Annual Report . Busey accounts for intersegment revenue and transfers at current market value. Following is a summary of selected financial information for Busey’s operating segments. The “other” category included in the tables below consists of the parent company, First Busey Risk Management, Inc. until its dissolution on December 18, 2023, and the elimination of intercompany transactions (dollars in thousands) : Goodwill Total Assets As of As of March 31, December 31, March 31, December 31, Operating segment Banking $ 294,773 $ 294,773 $ 11,722,919 $ 12,125,298 Wealth Management 14,108 14,108 107,251 103,147 FirsTech 8,992 8,992 50,643 51,600 Other — — 6,645 3,370 Consolidated total $ 317,873 $ 317,873 $ 11,887,458 $ 12,283,415 Three Months Ended March 31, 2024 2023 Net interest income Banking $ 79,533 $ 89,890 FirsTech 13 13 Other (3,779) (4,046) Total net interest income $ 75,767 $ 85,857 Noninterest income Banking $ 13,472 $ 12,421 Wealth Management 15,712 14,926 FirsTech 5,971 5,674 Other (155) (1,173) Total noninterest income $ 35,000 $ 31,848 Noninterest expense Banking $ 52,387 $ 54,651 Wealth Management 9,136 8,534 FirsTech 5,866 5,739 Other 3,380 1,479 Total noninterest expense $ 70,769 $ 70,403 Income before income taxes Banking $ 35,580 $ 46,707 Wealth Management 6,576 6,392 FirsTech 118 (52) Other (7,314) (6,698) Total income before income taxes $ 34,960 $ 46,349 Net income Banking $ 26,492 $ 36,835 Wealth Management 4,998 4,858 FirsTech 86 (38) Other (5,351) (4,869) Total net income $ 26,225 $ 36,786

ACQUISITION

ACQUISITION	3 Months Ended
	Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
ACQUISITION	ACQUISITION Merchants and Manufacturers Bank Corporation Effective April 1, 2024, Busey completed its previously announced acquisition of M&M, pursuant to which Busey acquired M&M and its wholly-owned subsidiary, M&M Bank, through a merger transaction. This partnership adds M&M’s Life Equity Loan ® products to Busey’s existing suite of services and expands Busey’s presence in the suburban Chicago market. Busey will operate M&M Bank as a separate banking subsidiary of Busey until it is merged with Busey Bank, which is expected to occur in June 2024. At the time of the bank merger, M&M Bank’s banking centers will become banking centers of Busey Bank, except for M&M’s banking center located at 990 Essington Rd., Joliet, Illinois, which is expected to be closed in connection with the bank merger. At the effective time of the Merger, each share of M&M common stock converted to the right to receive, at the election of each stockholder and subject to proration and adjustment as provided in the Merger Agreement, either (1) $117.74 in cash (“Cash Election”), (2) 5.7294 shares of Busey common stock (“Share Election”), or (3) mixed consideration of $34.55 in cash and 4.0481 shares of Busey common stock (“Mixed Election”). Most of the M&M common stockholders who submitted an election form by the election deadline made the Share Election to receive their Merger consideration solely in the form of shares of Busey common stock. As a result of the elections of M&M common stockholders, and in accordance with the proration and adjustment provisions of the Merger Agreement, the Merger consideration paid to M&M common stockholders was comprised of an aggregate of approximately 1,429,304 shares of Busey common stock and an aggregate of approximately $12.2 million in cash, allocated as follows for each share of M&M stock: (1) $117.74 in cash for the Cash Election, (2) $5.3966 in cash and 5.4668 shares of Busey common stock for the Share Election, and (3) $34.55 in cash and 4.0481 shares of Busey common stock for the Mixed Election. Pursuant to the terms of the Merger Agreement, M&M common stockholders that did not make an election or submit a properly completed election form by the election deadline of March 29, 2024, received cash consideration of $117.74 for each share of M&M common stock held. No fractional shares of Busey common stock were issued in the Merger. Fractional shares were paid in cash at the rate of $23.32 per share. This transaction was accounted for using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed, and consideration exchanged was recorded at estimated fair values on April 1, 2024, the date of acquisition. Fair values will be subject to refinement for up to one year after the closing date as additional information regarding the closing date fair values becomes available. During the three months ended March 31, 2024, Busey incurred $0.3 million in pre-tax acquisition expenses, comprised primarily of legal expenses, related to the acquisition of M&M.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net income	$ 26,225	$ 36,786

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

SIGNIFICANT ACCOUNTING POLICI_2

SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations First Busey Corporation, a Nevada corporation organized in 1980, is a $11.9 billion financial holding company headquartered in Champaign, Illinois. Busey’s common stock is traded on The Nasdaq Global Select Market under the symbol “BUSE.” First Busey operates and reports its business in three segments: Banking, Wealth Management, and FirsTech. • The Banking operating segment provides a full range of banking services to individual and corporate customers through its banking center network in Illinois; the St. Louis, Missouri metropolitan area; southwest Florida; and Indianapolis, Indiana. • The Wealth Management operating segment provides a full range of asset management, investment, brokerage, fiduciary, philanthropic advisory, tax preparation, and farm management services to individuals, businesses, and foundations. • The FirsTech operating segment provides comprehensive and innovative payment technology solutions including online, mobile, and voice-recognition bill payments; money management and credit card networks; direct debit services; lockbox remittance processing for payments made by mail; and walk-in payments. FirsTech also provides additional tools to help clients with billing, reconciliation, bill reminders, and treasury services. For additional information about First Busey's operating segments, see “ Note 15. Operating Segments and Related Information .”
Basis of Financial Statement Presentation	Basis of Financial Statement Presentation These unaudited consolidated financial statements and related notes should be read in conjunction with the audited consolidated financial statements included in Busey's 2023 Annual Report . These interim unaudited consolidated financial statements serve to update our 2023 Annual Report and may not include all information and notes necessary to constitute a complete set of financial statements. We prepared these unaudited consolidated financial statements in conformity with GAAP. We have eliminated intercompany accounts and transactions. We have also reclassified certain prior year amounts to conform to the current period presentation. These reclassifications did not have a material impact on our consolidated financial condition or results of operations. In our opinion, the unaudited consolidated financial statements reflect all normal, recurring adjustments needed to present fairly our results for the interim periods. The results of operations for interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.
Use of Estimates	Use of Estimates In preparing the accompanying unaudited consolidated financial statements in conformity with GAAP, Busey’s management is required to make estimates and assumptions that affect the amounts reported in the financial statements and the disclosures provided. Actual results could differ from those estimates. Material estimates which are particularly susceptible to significant change in the near term relate to the fair value of debt securities available for sale, fair value of assets acquired and liabilities assumed in business combinations, goodwill, income taxes, and the determination of the ACL.
Impact of Recently Adopted Accounting Standards	Impact of Recently Adopted Accounting Standards In March 2023, the FASB issued ASU 2023‑02 “Investments—Equity Method and Joint Ventures (Topic 323),” permitting an election to use the proportional amortization method to account for equity investments made primarily for the purpose of receiving income tax credits and other income tax benefits, regardless of the tax credit program from which the income tax credits are received, provided that certain conditions are met. The proportional amortization method results in the cost of the investment being amortized in proportion to the income tax credits and other income tax benefits received, with the amortization of the investment and the income tax credits being presented net in the income statement as a component of income tax expense. Busey adopted this standard on a modified retrospective basis on January 1, 2024. Upon adoption, Busey recorded an after-tax decrease to retained earnings of $1.4 million for the cumulative effect of adopting ASU 2023‑02. This transition adjustment included a $2.4 million decrease in other assets, a $0.5 million decrease in other liabilities, and a $0.5 million increase in deferred tax assets. In March 2023, the FASB issued ASU 2023‑01 “Leases (Topic 842): Common Control Arrangements,” which requires amortization over the useful life of leasehold improvements (not the lease term) when the lease is between entities under common control, and any value of such leasehold improvements remaining at the end of the lease term is to be accounted for as a transfer between entities under common control. Busey adopted this standard on a prospective basis on January 1, 2024. Adoption of this standard did not have a material impact on Busey’s financial position or results of operations. In June 2022, the FASB issued ASU 2022-03 “Fair Value Measurements (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions,” which clarifies that contractual restrictions on the sale of equity securities are not considered in measuring the fair value of those equity securities, and further that contractual sale restrictions cannot be recognized and measured as a separate unit of account. Busey adopted this standard on a prospective basis on January 1, 2024. Adoption of this standard did not have a material impact on Busey’s financial position or results of operations. Recently Issued Accounting Standards Not Yet Adopted In March 2024, the FASB issued ASU 2024-01 “Compensation-Stock Compensation (Topic 718): Scope Application of Profits Interest and Similar Awards” to clarify that certain “profits interests” are within the scope of Topic 718 by amending the language and providing illustrative examples on how the scope guidance in paragraph 718-10-15-3 should be applied. This update is intended to improve clarity of the accounting standards codification, not to change the guidance. This update may be applied on a retrospective or prospective basis and will be effective for Busey for annual and interim periods beginning January 1, 2025. Early adoption is permitted. Busey is currently evaluating the potential effects of adoption of this ASU on its financial position and results of operations. In December 2023, the FASB issued ASU 2023‑09 “Income Taxes (Topic 740): Improvements to Income Tax Disclosures,” which requires more detailed disclosures of income taxes paid net of refunds received, income from continuing operations before income tax expense or benefit, and income tax expense from continuing operations. This standard is to be applied on a prospective basis, with retrospective application permitted, and will be effective for Busey for annual reporting periods beginning with the fiscal year ending December 31, 2025. Busey does not expect adoption of this standard to have a material impact on its financial position or results of operations. In November 2023, the FASB issued ASU 2023‑07 “Segment Reporting Topic 820): Improvements to Reportable Segment Disclosures” requiring enhanced disclosures related to significant segment expenses. This standard is to be applied on a retrospective basis and is effective for Busey for annual reporting periods beginning with the fiscal year ending December 31, 2024, and for interim reporting periods within fiscal years starting January 1, 2025. Busey does not expect adoption of this standard to have a material impact on the Company’s financial position or results of operations. In October 2023, the FASB issued ASU 2023‑06 “Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative” which aligns certain GAAP disclosure requirements with the SEC’s disclosure requirements, in order to better facilitate comparisons between entities that are subject to the SEC’s existing disclosures with entities that were not previously subject to the SEC’s requirements. Amendments in this update should be applied prospectively, and the effective date for Busey for each amendment in this ASU will be the date on which the SEC removes the related disclosure from Regulation S‑X or Regulation S‑K. Early adoption is prohibited. Busey does not expect adoption of this standard to have a material impact on its financial position or results of operations.
Subsequent Events	Subsequent Events Busey has evaluated subsequent events for potential recognition and/or disclosure through the date the unaudited consolidated financial statements included in this Quarterly Report were issued. Busey issued a Form 8‑K on April 1 , 202 4 , announcing completion of its acquisition of M&M on that date. Merger consideration paid to M&M common stockholders was comprised of an aggregate of 1,429,304 shares of Busey common stock and an aggregate of $12.2 million in cash. For additional information about Busey’s acquisition of M&M, see “ Not e. 16 Acquisition .” There were no other significant events subsequent to the quarter ended March 31, 2024, through the filing date of these unaudited consolidated financial statements.

DEBT SECURITIES (Tables)

DEBT SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Schedule of amortized cost, unrealized gains and losses and fair values of securities classified available for sale and held to maturity	The tables below provide the amortized cost, unrealized gains and losses, and fair values of debt securities summarized by major category (dollars in thousands) : As of March 31, 2024 Amortized Unrealized Fair Gross Gains Gross Losses Debt securities available for sale U.S. Treasury securities $ 749 $ — $ (7) $ 742 Obligations of U.S. government corporations and agencies 5,777 1 (35) 5,743 Obligations of states and political subdivisions 1 168,997 20 (18,091) 150,926 Asset-backed securities 1,2 462,082 — (384) 461,698 Commercial mortgage-backed securities 108,006 — (15,443) 92,563 Residential mortgage-backed securities 1,223,453 2 (201,722) 1,021,733 Corporate debt securities 177,212 85 (12,630) 164,667 Total debt securities available for sale $ 2,146,276 $ 108 $ (248,312) $ 1,898,072 Amortized Unrecognized Fair Gross Gains Gross Losses Debt securities held to maturity Commercial mortgage-backed securities $ 424,946 $ — $ (74,590) $ 350,356 Residential mortgage-backed securities 437,272 — (74,597) 362,675 Total debt securities held to maturity $ 862,218 $ — $ (149,187) $ 713,031 ___________________________________________ 1. Includes securities marked at par, with no gain or loss to report. 2. Gross gains were insignificant, rounding to zero thousand. As of December 31, 2023 Amortized Unrealized Fair Gross Gains Gross Losses Debt securities available for sale U.S. Treasury securities $ 16,031 $ — $ (85) $ 15,946 Obligations of U.S. government corporations and agencies 5,889 1 (58) 5,832 Obligations of states and political subdivisions 1 190,819 52 (18,026) 172,845 Asset-backed securities 470,046 — (1,823) 468,223 Commercial mortgage-backed securities 119,044 — (15,535) 103,509 Residential mortgage-backed securities 1 1,306,854 5 (195,547) 1,111,312 Corporate debt securities 225,947 128 (16,171) 209,904 Total debt securities available for sale $ 2,334,630 $ 186 $ (247,245) $ 2,087,571 Amortized Unrecognized Fair Gross Gains Gross Losses Debt securities held to maturity Commercial mortgage-backed securities $ 428,526 $ — $ (71,000) $ 357,526 Residential mortgage-backed securities 444,102 — (71,231) 372,871 Total debt securities held to maturity $ 872,628 $ — $ (142,231) $ 730,397 ___________________________________________ 1. Includes securities marked at par, with no gain or loss to report.
Maturities of debt securities	All mortgage-backed securities were issued by U.S. government corporations and agencies (dollars in thousands) : As of March 31, 2024 Amortized Fair Debt securities available for sale Due in one year or less $ 262,012 $ 222,566 Due after one year through five years 752,610 666,718 Due after five years through ten years 529,926 469,029 Due after ten years 601,728 539,759 Debt securities available for sale $ 2,146,276 $ 1,898,072 Debt securities held to maturity Due in one year or less $ 104,797 $ 88,589 Due after one year through five years 263,376 216,744 Due after five years through ten years 241,243 198,562 Due after ten years 252,802 209,136 Debt securities held to maturity $ 862,218 $ 713,031
Gains and losses on debt securities	Realized gains and losses related to sales and calls of debt securities available for sale are summarized as follows (dollars in thousands) : Three Months Ended March 31, 2024 2023 Realized gains and losses on debt securities Gross gains on debt securities $ 1 $ 10 Gross (losses) on debt securities 1 (6,803) (6) Realized net gains (losses) on debt securities $ (6,802) $ 4 ___________________________________________ 1. During the first quarter of 2024, Busey sold available-for-sale debt securities with a book value of approximately $108.2 million for a pre-tax loss of $6.8 million, as part of a balance sheet repositioning strategy. The loss on the sale of securities was offset by a pre-tax gain of $7.5 million realized on the sale of mortgage servicing rights on approximately $923.5 million of one- to four-family mortgage loans.
Debt securities in an unrealized loss position	The following information pertains to debt securities with gross unrealized or unrecognized losses, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (dollars in thousands) : As of March 31, 2024 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Debt securities available for sale U.S. Treasury securities $ — $ — $ 742 $ (7) $ 742 $ (7) Obligations of U.S. government corporations and agencies — — 5,629 (35) 5,629 (35) Obligations of states and political subdivisions 8,524 (68) 134,945 (18,023) 143,469 (18,091) Asset-backed securities — — 253,231 (384) 253,231 (384) Commercial mortgage-backed securities — — 92,563 (15,443) 92,563 (15,443) Residential mortgage-backed securities 165 (1) 1,021,383 (201,721) 1,021,548 (201,722) Corporate debt securities 4,313 (102) 152,739 (12,528) 157,052 (12,630) Debt securities available for sale with gross unrealized losses $ 13,002 $ (171) $ 1,661,232 $ (248,141) $ 1,674,234 $ (248,312) 12 months or more Total Fair Unrecognized Fair Unrecognized Debt securities held to maturity Commercial mortgage-backed securities $ 350,356 $ (74,590) $ 350,356 $ (74,590) Residential mortgage-backed securities 362,675 (74,597) 362,675 (74,597) Debt securities held to maturity with gross unrecognized losses $ 713,031 $ (149,187) $ 713,031 $ (149,187) As of December 31, 2023 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Debt securities available for sale U.S. Treasury securities $ — $ — $ 15,946 $ (85) $ 15,946 $ (85) Obligations of U.S. government corporations and agencies — — 5,709 (58) 5,709 (58) Obligations of states and political subdivisions 11,442 (54) 146,797 (17,972) 158,239 (18,026) Asset-backed securities — — 468,223 (1,823) 468,223 (1,823) Commercial mortgage-backed securities — — 103,509 (15,535) 103,509 (15,535) Residential mortgage-backed securities 141 (1) 1,110,906 (195,546) 1,111,047 (195,547) Corporate debt securities 1,450 (10) 198,694 (16,161) 200,144 (16,171) Debt securities available for sale with gross unrealized losses $ 13,033 $ (65) $ 2,049,784 $ (247,180) $ 2,062,817 $ (247,245) 12 months or more Total Fair Unrecognized Fair Unrecognized Debt securities held to maturity Commercial mortgage-backed securities $ 357,526 $ (71,000) $ 357,526 $ (71,000) Residential mortgage-backed securities 372,871 (71,231) 372,871 (71,231) Debt securities held to maturity with gross unrecognized losses $ 730,397 $ (142,231) $ 730,397 $ (142,231) Additional information about debt securities in an unrealized or unrecognized loss position is presented in the tables below (dollars in thousands) : As of March 31, 2024 Available for Sale Held to Maturity Total Debt securities with gross unrealized or unrecognized losses, fair value $ 1,674,234 $ 713,031 $ 2,387,265 Gross unrealized or unrecognized losses on debt securities 248,312 149,187 397,499 Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses 14.8 % 20.9 % 16.7 % Count of debt securities 708 55 763 Count of debt securities in an unrealized or unrecognized loss position 654 55 709 As of December 31, 2023 Available for Sale Held to Maturity Total Debt securities with gross unrealized or unrecognized losses, fair value $ 2,062,817 $ 730,397 $ 2,793,214 Gross unrealized or unrecognized losses on debt securities 247,245 142,231 389,476 Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses 12.0 % 19.5 % 13.9 % Count of debt securities 835 55 890 Count of debt securities in an unrealized or unrecognized loss position 779 55 834

PORTFOLIO LOANS (Tables)

PORTFOLIO LOANS (Tables)	3 Months Ended
	Mar. 31, 2024
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Distribution of portfolio loans	Distributions of the loan portfolio by loan category and class is presented in the following table (dollars in thousands) : As of March 31, December 31, Commercial loans C&I and other commercial $ 1,828,711 $ 1,835,994 Commercial real estate 3,331,670 3,337,337 Real estate construction 445,860 461,717 Total commercial loans 5,606,241 5,635,048 Retail loans Retail real estate 1,708,663 1,720,455 Retail other 273,173 295,531 Total retail loans 1,981,836 2,015,986 Total portfolio loans 7,588,077 7,651,034 ACL (91,562) (91,740) Portfolio loans, net $ 7,496,515 $ 7,559,294
Schedule of financial instruments owned and pledged as collateral	The principal balance of loans Busey has pledged as collateral to the FHLB and Federal Reserve Bank for liquidity as set forth in the table below (dollars in thousands) : As of March 31, December 31, Pledged loans FHLB $ 4,821,485 $ 4,865,481 Federal Reserve Bank 724,971 722,914 Total pledged loans $ 5,546,456 $ 5,588,395 To secure its obligations under derivative contracts, Busey pledged cash and held collateral as follows (dollars in thousands) : As of March 31, December 31, Cash pledged to secure obligations under derivative contracts $ 34,210 $ 34,210 Collateral held to secure obligations under derivative contracts 24,860 19,280
Summary of risk grades segregated by category of portfolio loans (excluding accretable purchase accounting adjustments and clearings)	The following table is a summary of risk grades segregated by category and class of portfolio loans (dollars in thousands) : As of March 31, 2024 Pass Watch Special Substandard Substandard Total Commercial loans C&I and other commercial $ 1,491,166 $ 243,635 $ 37,711 $ 42,853 $ 13,346 $ 1,828,711 Commercial real estate 2,797,374 447,313 49,932 36,987 64 3,331,670 Real estate construction 410,089 22,483 7,743 5,301 244 445,860 Total commercial loans 4,698,629 713,431 95,386 85,141 13,654 5,606,241 Retail loans Retail real estate 1,692,013 9,371 922 2,689 3,668 1,708,663 Retail other 273,030 — — — 143 273,173 Total retail loans 1,965,043 9,371 922 2,689 3,811 1,981,836 Total portfolio loans $ 6,663,672 $ 722,802 $ 96,308 $ 87,830 $ 17,465 $ 7,588,077 As of December 31, 2023 Pass Watch Special Substandard Substandard Total Commercial loans C&I and other commercial $ 1,462,755 $ 296,416 $ 46,488 $ 27,733 $ 2,602 $ 1,835,994 Commercial real estate 2,827,030 431,427 48,545 29,492 843 3,337,337 Real estate construction 448,011 8,135 — 5,327 244 461,717 Total commercial loans 4,737,796 735,978 95,033 62,552 3,689 5,635,048 Retail loans Retail real estate 1,702,897 11,144 1,024 1,795 3,595 1,720,455 Retail other 295,374 — — — 157 295,531 Total retail loans 1,998,271 11,144 1,024 1,795 3,752 2,015,986 Total portfolio loans $ 6,736,067 $ 747,122 $ 96,057 $ 64,347 $ 7,441 $ 7,651,034
Risk grades of portfolio loans, further sorted by origination	Risk grades of portfolio loans and gross charge-offs are presented in the tables below by loan class, further sorted by origination year (dollars in thousands) : As of and For The Three Months Ended March 31, 2024 Term Loans Amortized Cost Basis by Origination Year Revolving Total Risk Grade Ratings 2024 2023 2022 2021 2020 Prior C&I and other commercial Pass $ 92,898 $ 261,771 $ 214,944 $ 156,831 $ 66,161 $ 154,099 $ 544,462 $ 1,491,166 Watch 4,869 58,913 49,671 14,389 23,226 27,759 64,808 243,635 Special Mention 665 239 7,964 2,654 677 3,264 22,248 37,711 Substandard 8,371 5,700 1,386 819 525 2,348 23,704 42,853 Substandard non-accrual — 75 — 117 66 1,388 11,700 13,346 Total commercial 106,803 326,698 273,965 174,810 90,655 188,858 666,922 1,828,711 Gross charge-offs — 5,130 — — — 88 — 5,218 Commercial real estate Pass 77,146 362,541 845,621 676,837 384,545 433,216 17,468 2,797,374 Watch 58,049 131,059 35,873 111,998 32,964 73,846 3,524 447,313 Special Mention 1,405 8,646 13,126 12,578 5,015 9,162 — 49,932 Substandard 1,362 5,626 2,677 18,821 3,337 5,114 50 36,987 Substandard non-accrual — 44 — — 20 — — 64 Total commercial real estate 137,962 507,916 897,297 820,234 425,881 521,338 21,042 3,331,670 Gross charge-offs — — — — — 96 — 96 Real estate construction Pass 58,333 177,437 72,325 75,282 2,458 3,332 20,922 410,089 Watch — 3,678 18,030 455 320 — — 22,483 Special Mention — 7,743 — — — — — 7,743 Substandard — 5,301 — — — — — 5,301 Substandard non-accrual — — — — — 244 — 244 Total real estate construction 58,333 194,159 90,355 75,737 2,778 3,576 20,922 445,860 Gross charge-offs — — — — — — — — Retail real estate Pass 19,533 240,662 376,623 378,955 153,995 313,080 209,165 1,692,013 Watch 805 832 2,873 2,242 937 401 1,281 9,371 Special Mention — 191 354 — — 377 — 922 Substandard — 136 1,049 519 45 935 5 2,689 Substandard non-accrual — — 527 65 253 1,982 841 3,668 Total retail real estate 20,338 241,821 381,426 381,781 155,230 316,775 211,292 1,708,663 Gross charge-offs — — — — — 52 — 52 Retail other Pass 1,458 78,006 83,891 20,205 5,438 3,546 80,486 273,030 Substandard non-accrual — — 93 49 — 1 — 143 Total retail other 1,458 78,006 83,984 20,254 5,438 3,547 80,486 273,173 Gross charge-offs — 3 — 23 — 68 — 94 Total portfolio loans $ 324,894 $ 1,348,600 $ 1,727,027 $ 1,472,816 $ 679,982 $ 1,034,094 $ 1,000,664 $ 7,588,077 Total gross charge-offs $ — $ 5,133 $ — $ 23 $ — $ 304 $ — $ 5,460 As of and For The Year Ended December 31, 2023 Term Loans Amortized Cost Basis by Origination Year Revolving Total Risk Grade Ratings 2023 2022 2021 2020 2019 Prior C&I and other commercial Pass $ 306,578 $ 220,847 $ 159,130 $ 71,025 $ 35,927 $ 143,078 $ 526,170 $ 1,462,755 Watch 78,603 65,703 21,421 23,919 7,035 21,293 78,442 296,416 Special Mention 792 8,224 2,917 1,076 686 3,274 29,519 46,488 Substandard 8,715 765 942 426 3,734 1,859 11,292 27,733 Substandard non-accrual 166 — 117 84 128 407 1,700 2,602 Total commercial 394,854 295,539 184,527 96,530 47,510 169,911 647,123 1,835,994 Gross charge-offs 284 — 420 — 316 1,409 — 2,429 Commercial real estate Pass 395,644 824,506 720,052 399,195 271,078 199,662 16,893 2,827,030 Watch 166,795 47,070 92,848 34,010 68,196 19,396 3,112 431,427 Special Mention 14,313 10,507 12,446 4,968 3,297 3,014 — 48,545 Substandard 1,796 188 18,862 2,938 1,802 3,856 50 29,492 Substandard non-accrual 47 79 85 23 — 609 — 843 Total commercial real estate 578,595 882,350 844,293 441,134 344,373 226,537 20,055 3,337,337 Gross charge-offs — — — — — 953 — 953 Real estate construction Pass 204,952 128,462 85,086 2,616 1,323 2,934 22,638 448,011 Watch 2,859 4,406 507 322 41 — — 8,135 Substandard 5,327 — — — — — — 5,327 Substandard non-accrual — — — — — 244 — 244 Total real estate construction 213,138 132,868 85,593 2,938 1,364 3,178 22,638 461,717 Gross charge-offs — — — — — — — — Retail real estate Pass 243,400 376,922 411,723 156,762 70,099 256,571 187,420 1,702,897 Watch 1,096 4,137 2,442 954 536 234 1,745 11,144 Special Mention 286 358 — — — 380 — 1,024 Substandard 69 72 292 49 80 997 236 1,795 Substandard non-accrual — 528 121 267 100 1,960 619 3,595 Total retail real estate 244,851 382,017 414,578 158,032 70,815 260,142 190,020 1,720,455 Gross charge-offs — 5 — 29 72 301 — 407 Retail other Pass 88,885 92,931 23,019 6,701 4,597 854 78,387 295,374 Substandard non-accrual — 93 62 — — 2 — 157 Total retail other 88,885 93,024 23,081 6,701 4,597 856 78,387 295,531 Gross charge-offs 5 71 172 5 3 373 — 629 Total portfolio loans $ 1,520,323 $ 1,785,798 $ 1,552,072 $ 705,335 $ 468,659 $ 660,624 $ 958,223 $ 7,651,034 Total gross charge-offs $ 289 $ 76 $ 592 $ 34 $ 391 $ 3,036 $ — $ 4,418
Summary of portfolio loans that are past due and still accruing or on a non-accrual status	An analysis of the amortized cost basis of portfolio loans that are past due and still accruing, or on a non-accrual status, is as follows (dollars in thousands) : As of March 31, 2024 Loans past due, still accruing Non-accrual 30-59 Days 60-89 Days 90+Days Past due and non-accrual loans Commercial loans: C&I and other commercial $ 43 $ — $ — $ 13,346 Commercial real estate 3,174 338 — 64 Real estate construction — — — 244 Past due and non-accrual commercial loans 3,217 338 — 13,654 Retail loans: Retail real estate 2,869 385 77 3,668 Retail other 530 102 11 143 Past due and non-accrual retail loans 3,399 487 88 3,811 Total past due and non-accrual loans $ 6,616 $ 825 $ 88 $ 17,465 As of December 31, 2023 Loans past due, still accruing Non-accrual 30-59 Days 60-89 Days 90+Days Past due and non-accrual loans Commercial loans: C&I and other commercial $ — $ 214 $ — $ 2,602 Commercial real estate 752 — — 843 Real estate construction 24 — — 244 Past due and non-accrual commercial loans 776 214 — 3,689 Retail loans: Retail real estate 2,781 927 366 3,595 Retail other 886 195 9 157 Past due and non-accrual retail loans 3,667 1,122 375 3,752 Total past due and non-accrual loans $ 4,443 $ 1,336 $ 375 $ 7,441
Schedule of loan modifications made to borrowers experiencing financial difficulty	The following tables present the amortized cost basis of loans that were modified—specifically in the form of (1) principal forgiveness, (2) an interest rate reduction, (3) an other-than-insignificant payment deferral, and/or (4) a term extension—for borrowers experiencing financial difficulty during the periods indicated, disaggregated by class of financing receivable and type of concession granted (dollars in thousands) : Three Months Ended March 31, 2024 Payment Deferral 1 % of Total Class of Financing Receivable Term Extension 2 % of Total Class of Financing Receivable Modified Loans C&I and other commercial $ 10,000 0.5 % $ 17,155 0.9 % Commercial real estate — — % 1,705 0.1 % Total of loans modified during the period $ 10,000 0.1 % $ 18,860 0.2 % ___________________________________________ 1. One loan was modified and classified as non-accrual during the three months ended March 31, 2024. 2. Modifications to extend loan terms also included, in some cases, interest rate increases during the extension period. All modifications were for loans classified as substandard. Three Months Ended March 31, 2023 Payment Deferral 1 % of Total Class of Financing Receivable 2 Term Extension 3 % of Total Class of Financing Receivable Modified Loans C&I and other commercial $ 489 — % $ 25,155 1.3 % Commercial real estate — — % 12,698 0.4 % Total of loans modified during the period 4 $ 489 — % $ 37,853 0.5 % ___________________________________________ 1. Loans with payment deferrals were modified to defer all principal payments until the end of the loan terms, which were shortened. Regular interest payments continue to be required during the deferral period. 2. Loans with payment deferrals represent an insignificant portion of commercial loans and total loans, rounding to zero percent. 3. Modifications to extend loan terms also included, in most cases, interest rate increases during the extension period. 4. All modifications were for loans classified as substandard. Three Months Ended March 31, 2024 2023 Weighted Average Term Extension Weighted Average Term Extension Effects of Loan Modifications C&I and other commercial 19.1 months 9.1 months Commercial real estate 2.0 months 5.8 months Total effect 17.6 months 8.0 months No loans to borrowers experiencing financial difficulty had a payment default during the three months ended March 31, 2024 or 2023, after having been modified during the 12 months before that default. A default occurs when a loan is 90 days or more past due or transferred to non-accrual status. Busey closely monitors the performance of the loans that are modified to borrowers experiencing financial difficulty to understand the effectiveness of its modification efforts. The following table depicts the payment performance of loans modified during the last twelve months (dollars in thousands) : As of March 31, 2024 Current 30-89 Days 90+ Days Non-accrual Modified Loans C&I and other commercial $ 21,641 $ — $ — $ 10,000 Commercial real estate 3,009 — — — Real estate construction 5,301 — — — Amortized cost of modified loans $ 29,951 $ — $ — $ 10,000
Schedule of details of impaired loans, segregated by category	Average recorded investment is calculated using the most recent four quarters (dollars in thousands) : As of March 31, 2024 Unpaid Recorded Investment Average With No With Total Related Loans evaluated individually Commercial loans: C&I and other commercial $ 20,372 $ 2,197 $ 10,920 $ 13,117 $ 7,498 $ 6,553 Commercial real estate — — — — — 2,618 Commercial loans evaluated individually 20,372 2,197 10,920 13,117 7,498 9,171 Retail loans: Retail real estate 213 61 25 86 25 289 Retail loans evaluated individually 213 61 25 86 25 289 Total loans evaluated individually $ 20,585 $ 2,258 $ 10,945 $ 13,203 $ 7,523 $ 9,460 As of December 31, 2023 Unpaid Recorded Investment Average With No With Total Related Loans evaluated individually Commercial loans: C&I and other commercial $ 7,283 $ 585 $ 1,785 $ 2,370 $ 785 $ 5,244 Commercial real estate 2,600 610 85 695 85 3,865 Real estate construction — — — — — 49 Commercial loans evaluated individually 9,883 1,195 1,870 3,065 870 9,158 Retail loans: Retail real estate 213 61 25 86 25 790 Retail loans evaluated individually 213 61 25 86 25 790 Total loans evaluated individually $ 10,096 $ 1,256 $ 1,895 $ 3,151 $ 895 $ 9,948
Schedule of activity on the allowance for loan losses	The following tables summarize activity in the ACL attributable to each loan class. Allocation of a portion of the ACL to one loan class does not preclude its availability to absorb losses in other loan classes (dollars in thousands) : Three Months Ended March 31, 2024 C&I and Other Commercial Commercial Real Estate Retail Retail Other Total ACL balance, December 31, 2023 $ 21,256 $ 35,465 $ 5,163 $ 26,298 $ 3,558 $ 91,740 Provision for credit losses 10,125 (1,864) (491) (2,093) (639) 5,038 Charged-off (5,218) (96) — (52) (94) (5,460) Recoveries 44 — 41 128 31 244 ACL balance, March 31, 2024 $ 26,207 $ 33,505 $ 4,713 $ 24,281 $ 2,856 $ 91,562 Three Months Ended March 31, 2023 C&I and Other Commercial Commercial Real Estate Retail Retail Other Total ACL balance, December 31, 2022 $ 23,860 $ 38,299 $ 6,457 $ 18,193 $ 4,799 $ 91,608 Provision for credit losses 695 (3,359) (1,329) 5,948 (1,002) 953 Charged-off (400) (539) — (5) (237) (1,181) Recoveries 121 20 31 119 56 347 ACL balance, March 31, 2023 $ 24,276 $ 34,421 $ 5,159 $ 24,255 $ 3,616 $ 91,727
Schedule of allowance for loan losses and recorded investments in portfolio loans, by category	The following tables present the ACL and amortized cost of portfolio loans by loan category and class (dollars in thousands) : As of March 31, 2024 Portfolio Loans ACL Attributed to Portfolio Loans Collectively Individually Total Collectively Individually Total Portfolio loans and related ACL Commercial loans: C&I and other commercial $ 1,815,594 $ 13,117 $ 1,828,711 $ 18,709 $ 7,498 $ 26,207 Commercial real estate 3,331,670 — 3,331,670 33,505 — 33,505 Real estate construction 445,860 — 445,860 4,713 — 4,713 Commercial loans and related ACL 5,593,124 13,117 5,606,241 56,927 7,498 64,425 Retail loans: Retail real estate 1,708,577 86 1,708,663 24,256 25 24,281 Retail other 273,173 — 273,173 2,856 — 2,856 Retail loans and related ACL 1,981,750 86 1,981,836 27,112 25 27,137 Portfolio loans and related ACL $ 7,574,874 $ 13,203 $ 7,588,077 $ 84,039 $ 7,523 $ 91,562 As of December 31, 2023 Portfolio Loans ACL Attributed to Portfolio Loans Collectively Individually Total Collectively Individually Total Portfolio loans and related ACL Commercial loans: C&I and other commercial $ 1,833,624 $ 2,370 $ 1,835,994 $ 20,471 $ 785 $ 21,256 Commercial real estate 3,336,642 695 3,337,337 35,380 85 35,465 Real estate construction 461,717 — 461,717 5,163 — 5,163 Commercial loans and related ACL 5,631,983 3,065 5,635,048 61,014 870 61,884 Retail loans: Retail real estate 1,720,369 86 1,720,455 26,273 25 26,298 Retail other 295,531 — 295,531 3,558 — 3,558 Retail loans and related ACL 2,015,900 86 2,015,986 29,831 25 29,856 Portfolio loans and related ACL $ 7,647,883 $ 3,151 $ 7,651,034 $ 90,845 $ 895 $ 91,740

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Summary of lease-related balances	The following table summarizes lease-related information and balances Busey reported in its Consolidated Balance Sheets (Unaudited) for the periods presented (dollars in thousands) : As of March 31, December 31, Lease balances Right of use assets $ 10,590 $ 11,027 Lease liabilities 10,896 11,308 Supplemental information Year through which lease terms extend 2037 2037 Weighted average remaining lease term 8.26 years 8.39 years Weighted average discount rate 3.61 % 3.59 %
Schedule of lease costs and other lease information	The following table represents lease costs and cash flows related to leases for the periods presented (dollars in thousands) : Three Months Ended March 31, 2024 2023 Lease costs Operating lease costs $ 535 $ 628 Variable lease costs 14 5 Short-term lease costs 13 6 Total lease cost 1 $ 562 $ 639 Cash flows related to leases Cash paid for amounts included in the measurement of lease liabilities: Operating lease cash flows – Fixed payments $ 507 $ 570 Operating lease cash flows – Liability reduction 411 479 Right of use assets obtained during the period in exchange for operating lease liabilities — 4 ___________________________________________ 1. Lease costs are included in net occupancy and equipment expense in the Consolidated Statements of Income (Unaudited).
Schedule of future undiscounted lease payments	Busey was obligated under noncancelable operating leases for office space and other commitments. Future undiscounted lease payments with initial terms of one year or more, are as follows (dollars in thousands) : As of Rent commitments Remainder of 2024 $ 1,515 2025 1,768 2026 1,443 2027 1,277 2028 1,255 2029 1,278 Thereafter 4,200 Total undiscounted cash flows 12,736 Less: Amounts representing interest 1,840 Present value of net future minimum lease payments $ 10,896
Summary of revenue recorded in connection with leases	Revenues recorded in connection with these leases, reported in Other income on our Consolidated Statements of Income (Unaudited), are summarized as follows (dollars in thousands) : Three Months Ended March 31, 2024 2023 Rental income $ 202 $ 191

DEPOSITS (Tables)

DEPOSITS (Tables)	3 Months Ended
	Mar. 31, 2024
Deposits [Abstract]
Schedule of composition of deposits	The composition of Busey’s deposits is as follows (dollars in thousands) : As of March 31, December 31, Deposits Noninterest-bearing demand deposits $ 2,784,338 $ 2,834,655 Interest-bearing transaction deposits 2,397,937 2,717,139 Saving deposits and money market deposits 3,200,738 2,920,088 Time deposits 1,577,178 1,819,274 Total deposits $ 9,960,191 $ 10,291,156 Additional information about Busey’s deposits follows (dollars in thousands) : As of March 31, December 31, Brokered savings deposits and money market deposits $ 6,001 $ 6,001 Brokered time deposits — 285 Aggregate amount of time deposits with a minimum denomination of $100,000 898,433 1,072,189 Aggregate amount of time deposits with a minimum denomination that meets or exceeds the FDIC insurance limit of $250,000 326,794 386,286
Schedule of maturities of time deposits	Scheduled maturities of time deposits are as follows (dollars in thousands) : As of Time deposits by schedule of maturities Remainder of 2024 $ 1,371,431 2025 156,304 2026 22,905 2027 13,209 2028 10,150 2029 2,743 Thereafter 436 Time deposits $ 1,577,178

BORROWINGS (Tables)

BORROWINGS (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of distribution of securities sold under agreements to repurchase and short-term borrowings and weighted average interest rates	Securities sold under agreements to repurchase were as follows (dollars in thousands) : As of March 31, December 31, Securities sold under agreements to repurchase $ 147,175 $ 187,396 Weighted average rate for securities sold under agreements to repurchase 2.96 % 3.26 %
Schedule of short-term borrowings	Short-term borrowings are summarized as follows (dollars in thousands) : As of March 31, December 31, Short-term borrowings Term Loan, current portion due within 12 months $ — $ 12,000 Total short-term debt $ — $ 12,000
Summary of long-term debt	Long-term debt is summarized as follows (dollars in thousands) : As of March 31, December 31, Long-term debt Term Loan $ — $ 18,000 Total long-term debt $ — $ 18,000
Schedule of unamortized debt issuance cost	Unamortized debt issuance costs related to Busey’s subordinated notes are presented in the following table (dollars in thousands) : As of March 31, December 31, Unamortized debt issuance costs Subordinated notes issued in 2020 $ 610 $ 735 Subordinated notes issued in 2022 1,290 1,383 Total unamortized debt issuance costs $ 1,900 $ 2,118

REGULATORY CAPITAL (Tables)

REGULATORY CAPITAL (Tables)	3 Months Ended
	Mar. 31, 2024
Banking and Thrift, Other Disclosure [Abstract]
Schedule of applicable holding company and bank regulatory capital requirements	The following tables summarize regulatory capital requirements applicable to Busey and Busey Bank (dollars in thousands) : As of March 31, 2024 Actual Minimum Minimum Amount Ratio Amount Ratio Amount Ratio Common equity Tier 1 capital to risk weighted assets First Busey $ 1,166,919 13.45 % $ 390,433 4.50 % $ 563,958 6.50 % Busey Bank $ 1,365,033 15.79 % $ 389,113 4.50 % $ 562,052 6.50 % Tier 1 capital to risk weighted assets First Busey $ 1,240,919 14.30 % $ 520,577 6.00 % $ 694,103 8.00 % Busey Bank $ 1,365,033 15.79 % $ 518,817 6.00 % $ 691,756 8.00 % Total capital to risk weighted assets First Busey $ 1,557,137 17.95 % $ 694,103 8.00 % $ 867,628 10.00 % Busey Bank $ 1,456,250 16.84 % $ 691,756 8.00 % $ 864,695 10.00 % Leverage ratio of Tier 1 capital to average assets First Busey $ 1,240,919 10.46 % $ 474,678 4.00 % N/A N/A Busey Bank $ 1,365,033 11.53 % $ 473,422 4.00 % $ 591,777 5.00 % As of December 31, 2023 Actual Minimum Minimum Amount Ratio Amount Ratio Amount Ratio Common equity Tier 1 capital to risk weighted assets First Busey $ 1,155,973 13.09 % $ 397,331 4.50 % $ 573,923 6.50 % Busey Bank $ 1,362,962 15.48 % $ 396,128 4.50 % $ 572,185 6.50 % Tier 1 capital to risk weighted assets First Busey $ 1,229,973 13.93 % $ 529,775 6.00 % $ 706,367 8.00 % Busey Bank $ 1,362,962 15.48 % $ 528,171 6.00 % $ 704,228 8.00 % Total capital to risk weighted assets First Busey $ 1,540,318 17.44 % $ 706,367 8.00 % $ 882,958 10.00 % Busey Bank $ 1,448,307 16.45 % $ 704,228 8.00 % $ 880,285 10.00 % Leverage ratio of Tier 1 capital to average assets First Busey $ 1,229,973 10.08 % $ 488,315 4.00 % N/A N/A Busey Bank $ 1,362,962 11.19 % $ 487,103 4.00 % $ 608,879 5.00 %

TAX CREDIT AND OTHER INVESTME_2

TAX CREDIT AND OTHER INVESTMENTS IN UNCONSOLIDATED ENTITIES (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, All Other Investments [Abstract]
Schedule of investments	Busey’s investments in these unconsolidated entities and related unfunded investment obligations are reflected in other assets and other liabilities on the Consolidated Balance Sheets (Unaudited), and are summarized in the table below for the periods indicated (dollars in thousands) : As of Location March 31, December 31, Investments in unconsolidated entities Funded investments Other assets $ 64,516 $ 68,516 Unfunded investments Other assets 56,362 58,552 Investments in unconsolidated entities $ 120,878 $ 127,068 Unfunded investment obligations Other liabilities $ 56,362 $ 58,552 Upon adoption of ASU 2023-02 on January 1, 2024, Busey elected to apply the proportional amortization method in accounting for investments in tax-advantaged projects. Income tax credits and other tax benefits, net of investment amortization, were included as a component of our estimated annual effective tax rate used for the calculation of income taxes presented in the Consolidated Statements of Income (Unaudited). These income tax credits and other benefits, along with the investment amortization, are presented in the table below (dollars in thousands) : Three Months Ended March 31, 2024 Tax effects of investments in tax-advantaged projects Income tax credits and other tax benefits $ 4,101 Amortization of investments in tax-advantaged projects 3,647

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of changes in the Company's stock option awards	Busey has outstanding stock options assumed from acquisitions. A summary of the status of, and changes in, the Company's stock option awards for the three months ended March 31, 2024, follows: Options Shares Weighted- Weighted- Outstanding at December 31, 2023 21,266 $ 23.53 2.88 years Forfeited (880) 23.53 Outstanding at March 31, 2024 20,386 23.53 2.63 years Exercisable at March 31, 2024 20,386 23.53 2.63 years
Summary of changes in the Company's RSU, PSU, and DSU awards	A summary of changes in Busey’s RSU awards for the three months ended March 31, 2024, is as follows: RSU Awards Shares Weighted- Nonvested at December 31, 2023 1,041,444 $ 22.05 Granted 189,179 23.35 Dividend equivalents earned 10,219 24.46 Vested (7,681) 23.23 Forfeited (5,347) 23.38 Nonvested at March 31, 2024 1,227,814 22.25 A summary of changes in Busey’s PSU awards for the three months ended March 31, 2024, is as follows: PSU Awards Shares 1 Weighted- Nonvested at December 31, 2023 341,700 $ 22.67 Granted 189,208 23.35 Dividend equivalents earned 2 4,264 22.95 Vested 2 (4,264) 22.95 Forfeited (1,754) 22.76 Nonvested at March 31, 2024 529,154 $ 22.91 ___________________________________________ 1. Shares for PSU awards represent target shares at the grant date. 2. PSUs granted in 2021 vested on December 31, 2023, with performance determination and settlement activity in the first quarter of 2024. Final performance was determined to be at 50% of target. A summary of changes in Busey’s DSU awards for the three months ended March 31, 2024, is as follows: DSU Awards Shares Weighted- Nonvested at December 31, 2023 43,026 $ 20.41 Granted 35,847 23.35 Dividend equivalents earned 1,836 24.46 Vested (44,862) 20.57 Nonvested at March 31, 2024 35,847 23.35 Vested and outstanding at March 31, 2024 189,000 22.82
Schedule of Stock-based compensation expense	Busey recognized compensation expense related to nonvested RSU, PSU, and DSU awards, as well as the 2021 ESPP, as summarized in the table below (dollars in thousands) : Three Months Ended March 31, 2024 2023 Stock-based compensation expense RSU awards $ 894 $ 1,020 PSU awards 1 1,210 360 DSU awards 215 196 2021 ESPP 84 93 Total stock-based compensation expense $ 2,403 $ 1,669 ___________________________________________ 1. Expense for PSU awards with a market-based total stockholder return performance goal represents amounts based on target shares at the grant date. Expense for PSU awards with return on average tangible common equity and compounded annual revenue growth rate performance goals represents amounts based on target shares at the grant date, adjusted for performance expectations as of the date indicated.
Schedule of Unamortized stock-based compensation expense	Unamortized compensation expense related to nonvested RSU, PSU, and DSU awards is summarized in the table below (dollars in thousands) : As of March 31, December 31, Unamortized stock-based compensation RSU awards $ 10,259 $ 6,842 PSU awards 1 8,743 3,607 DSU awards 812 190 Total unamortized stock-based compensation $ 19,814 $ 10,639 Weighted average period over which expense is to be recognized 2.7 years 2.4 years ___________________________________________ 1. Unamortized expense for PSU awards with a market-based total stockholder return performance goal represents amounts based on target shares at grant date. Unamortized expense for PSU awards with return on average tangible common equity and compounded annual revenue growth rate performance goals represents amounts based on target shares at grant date, adjusted for performance expectations as of the date indicated.

OUTSTANDING COMMITMENTS AND C_2

OUTSTANDING COMMITMENTS AND CONTINGENT LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of contractual amount of exposure to off-balance-sheet risk	A summary of the contractual amount of Busey’s exposure to off-balance-sheet risk relating to the Company’s commitments to extend credit and standby letters of credit follows (dollars in thousands) : As of March 31, December 31, Financial instruments whose contract amounts represent credit risk Commitments to extend credit $ 2,118,621 $ 2,132,500 Standby letters of credit 46,967 43,996 Total commitments $ 2,165,588 $ 2,176,496

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of financial instruments owned and pledged as collateral	The principal balance of loans Busey has pledged as collateral to the FHLB and Federal Reserve Bank for liquidity as set forth in the table below (dollars in thousands) : As of March 31, December 31, Pledged loans FHLB $ 4,821,485 $ 4,865,481 Federal Reserve Bank 724,971 722,914 Total pledged loans $ 5,546,456 $ 5,588,395 To secure its obligations under derivative contracts, Busey pledged cash and held collateral as follows (dollars in thousands) : As of March 31, December 31, Cash pledged to secure obligations under derivative contracts $ 34,210 $ 34,210 Collateral held to secure obligations under derivative contracts 24,860 19,280
Summary of the interest-rate swaps designated as cash flow hedges	A summary of the interest-rate swaps designated as cash flow hedges is presented below (dollars in thousands) : As of Location March 31, December 31, Debt Swap Notional amount $ 50,000 $ 50,000 Weighted average fixed pay rates 1.79 % 1.79 % Weighted average variable 3-month Fallback Rate (SOFR) receive rates 5.62 % 5.61 % Weighted average maturity 0.46 years 0.71 years Prime Loan Swap Notional amount $ 300,000 $ 300,000 Weighted average fixed receive rates 4.81 % 4.81 % Weighted average variable Prime pay rates 8.50 % 8.50 % Weighted average maturity 4.85 years 5.10 years SOFR Loan Swap Notional amount $ 100,000 $ — Weighted average fixed receive rates 3.72 % — Weighted average maturity 4.93 years — Gross aggregate fair value of the swaps Gross aggregate fair value of swap assets Other assets $ 1,178 $ 1,293 Gross aggregate fair value of swap liabilities Other liabilities 30,303 25,411 Balances carried in AOCI Unrealized gains (losses) on cash flow hedges, net of tax AOCI $ (20,272) $ (16,694)
Reclassification of unrealized gains and losses from OCI	Busey expects to reclassify unrealized gains and losses from OCI to interest income and interest expense as shown in the following table, during the next 12 months (dollars in thousands) . Amounts actually recognized could differ from these expectations due to changes in interest rates, hedge de-designations, and the addition of other hedges subsequent to March 31, 2024. As of Unrealized gains (losses) in OCI expected to be recognized in income Unrealized losses expected to be reclassified from OCI to interest income $ (952) Unrealized gains expected to be reclassified from OCI to interest expense 483 Net unrealized gains (losses) in OCI expected to be recognized in net interest income $ (469)
Schedule of interest income (expense) recorded on swap transactions	Interest expense recorded on these swap transactions was as follows for the periods presented (dollars in thousands) : Three Months Ended March 31, 2024 2023 Interest on swap transactions Increase (decrease) in interest income on swap transactions $ (2,796) $ (2,192) (Increase) decrease in interest expense on swap transactions 483 383 Net increase (decrease) in net interest income on swap transactions $ (2,313) $ (1,809)
Summary of Net gains (losses) relating to these derivative instruments	The following table reflects the net gains (losses) relating to cash flow derivative instruments that were recorded in AOCI and the Consolidated Statements of Income (Unaudited) during the periods presented (dollars in thousands) : Three Months Ended March 31, 2024 2023 Unrealized gains (losses) on cash flow hedges Net gain (loss) recognized in OCI, net of tax $ (5,232) $ 3,050 (Gain) loss reclassified from OCI to interest income, net of tax 1,999 1,567 (Gain) loss reclassified from OCI to interest expense, net of tax (345) (274) Net change in unrealized gains (losses) on cash flow hedges, net of tax $ (3,578) $ 4,343 Changes in fair value of these derivative assets and liabilities were recorded in noninterest expense in the Consolidated Statements of Income (Unaudited) and are summarized as follows (dollars in thousands) : Three Months Ended March 31, Location 2024 2023 Interest rate swaps Pay floating, receive fixed Noninterest expense $ 5,480 $ (7,667) Pay fixed, receive floating Noninterest expense (5,480) 7,667 Net change in fair value of interest rate swaps $ — $ — Gains (losses) relating to these derivative instruments are summarized as follows for the periods presented (dollars in thousands) : Three Months Ended March 31, Location 2024 2023 Gains (losses) Interest rate lock commitments Mortgage revenue $ 267 $ 37 Forward sales commitments Mortgage revenue 9 (54) Interest rate lock commitments Other expense 5 — Forward sales commitments Other expense 51 —
Summary of fair values of derivative assets and liabilities recorded in consolidated balance sheet	Amounts and fair values of derivative assets and liabilities related to customer interest rate swaps recorded in the Consolidated Balance Sheets (Unaudited) are summarized as follows (dollars in thousands) : As of March 31, 2024 Derivative Asset Derivative Liability Notional Fair Notional Fair Derivatives not designated as hedging instruments Interest rate swaps – pay floating, receive fixed $ 71,472 $ 868 $ 606,862 $ 33,552 Interest rate swaps – pay fixed, receive floating 606,862 33,552 71,472 868 Total derivatives not designated as hedging instruments $ 678,334 $ 34,420 $ 678,334 $ 34,420 As of December 31, 2023 Derivative Asset Derivative Liability Notional Fair Notional Fair Derivatives not designated as hedging instruments Interest rate swaps – pay floating, receive fixed $ 177,883 $ 2,375 $ 485,253 $ 26,289 Interest rate swaps – pay fixed, receive floating 485,253 26,289 177,883 2,375 Total derivatives not designated as hedging instruments $ 663,136 $ 28,664 $ 663,136 $ 28,664 Amounts and fair values of mortgage banking derivatives included in the Consolidated Balance Sheets (Unaudited) are summarized as follows (dollars in thousands) : As of March 31, 2024 As of December 31, 2023 Location Notional Fair Notional Fair Mortgage banking derivative assets Interest rate lock commitments Other assets $ 9,123 $ 133 $ 3,477 $ 25 Forward sales commitments Other assets 2,772 9 1,761 11 Mortgage banking derivative assets $ 11,895 $ 142 $ 5,238 $ 36 Mortgage banking derivative liabilities Interest rate lock commitments Other liabilities $ 268 $ 3 $ 1,615 $ 10 Forward sales commitments Other liabilities 6,619 51 5,216 47 Mortgage banking derivative liabilities $ 6,887 $ 54 $ 6,831 $ 57
Schedule of notional amount and fair value of risk participation agreement	The risk participation agreements mature between June 2024 and January 2029, and are summarized as follows (dollars in thousands) : As of March 31, December 31, Risk participation agreements purchased Number of risk participation agreements 4 3 Notional amount $ 35,097 $ 34,251 Fair value 9 15 Risk participation agreements sold Number of risk participation agreements 1 1 Notional amount $ 20,001 20,001 Fair value — —

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of financial assets and financial liabilities measured at fair value on a recurring basis	The following tables summarize financial assets and financial liabilities measured at fair value on a recurring basis as of March 31, 2024, and December 31, 2023, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) : As of March 31, 2024 Level 1 Level 2 Level 3 Total Debt securities available for sale: U.S. Treasury securities $ — $ 742 $ — $ 742 Obligations of U.S. government corporations and agencies — 5,743 — 5,743 Obligations of states and political subdivisions — 150,926 — 150,926 Asset-backed securities — 461,698 — 461,698 Commercial mortgage-backed securities — 92,563 — 92,563 Residential mortgage-backed securities — 1,021,733 — 1,021,733 Corporate debt securities — 164,667 — 164,667 Equity securities — 9,790 — 9,790 Derivative assets — 35,740 9 35,749 Derivative liabilities — 64,777 — 64,777 As of December 31, 2023 Level 1 Level 2 Level 3 Total Debt securities available for sale: U.S. Treasury securities $ — $ 15,946 $ — $ 15,946 Obligations of U.S. government corporations and agencies — 5,832 — 5,832 Obligations of states and political subdivisions — 172,845 — 172,845 Asset-backed securities — 468,223 — 468,223 Commercial mortgage-backed securities — 103,509 — 103,509 Residential mortgage-backed securities — 1,111,312 — 1,111,312 Corporate debt securities — 209,904 — 209,904 Equity securities 448 9,364 — 9,812 Derivative assets — 29,993 15 30,008 Derivative liabilities — 54,132 — 54,132
Schedule of assets and liabilities measured at fair value on a non-recurring basis	The following tables summarize assets and liabilities measured at fair value on a non-recurring basis for the periods presented, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) : As of March 31, 2024 Level 1 Level 2 Level 3 Total Loans evaluated individually, net of related allowance $ — $ — $ 3,422 $ 3,422 Bank property held for sale with impairment — — 4,238 4,238 As of December 31, 2023 Level 1 Level 2 Level 3 Total Loans evaluated individually, net of related allowance $ — $ — $ 1,000 $ 1,000 Bank property held for sale with impairment — — 4,286 4,286
Schedule of quantitative information about Level 3 fair value measurements	The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis for which the Company has utilized Level 3 inputs to determine fair value (dollars in thousands) : As of March 31, 2024 Fair Value Valuation Unobservable Range Loans evaluated individually, net of related allowance $ 3,422 Appraisal of collateral Appraisal adjustments -25.0% to -100.0% (-68.7)% Bank property held for sale with impairment 4,238 Appraisal of collateral or real estate listing price Appraisal adjustments -9.0% to -64.9% (-39.1)% As of December 31, 2023 Fair Value Valuation Unobservable Range Loans evaluated individually, net of related allowance $ 1,000 Appraisal of collateral Appraisal adjustments -41.2% to -100.0% (-47.2)% Bank property held for sale with impairment 4,286 Appraisal of collateral or real estate listing price Appraisal adjustments -6.2% to -64.9% (-38.4)%
Schedule of estimated fair values of financial instruments	Estimated fair values of financial instruments that are not carried at fair value in Busey’s Consolidated Balance Sheets (Unaudited), segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows (dollars in thousands) : As of March 31, 2024 As of December 31, 2023 Carrying Fair Carrying Fair Financial assets Level 1 inputs: Cash and cash equivalents $ 591,071 $ 591,071 $ 719,581 $ 719,581 Level 2 inputs: Debt securities held to maturity 862,218 713,031 872,628 730,397 Loans held for sale 6,827 6,834 2,379 2,401 Accrued interest receivable 46,530 46,530 45,288 45,288 Level 3 inputs: Portfolio loans, net 7,496,515 7,293,871 7,559,294 7,276,905 Mortgage servicing rights 989 5,468 3,289 18,079 Other servicing rights 1,573 2,008 1,597 2,062 Financial liabilities Level 2 inputs: Time deposits $ 1,577,178 $ 1,559,643 $ 1,819,274 $ 1,804,905 Securities sold under agreements to repurchase 147,175 147,175 187,396 187,396 Short-term borrowings — — 12,000 12,034 Long-term debt — — 18,000 18,020 Junior subordinated debt owed to unconsolidated trusts 72,040 58,776 71,993 57,153 Accrued interest payable 26,707 26,707 28,418 28,418 Level 3 inputs: Subordinated notes, net of unamortized issuance costs 223,100 204,750 222,882 200,000

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of computation of earnings per common share	Earnings per common share have been computed as follows (dollars in thousands, except per share amounts) : Three Months Ended March 31, 2024 2023 Net income $ 26,225 $ 36,786 Weighted average number of common shares outstanding, basic 55,416,589 55,397,989 Dilutive effect of common stock equivalents: Warrants — 1,296 RSU awards 653,437 651,777 PSU awards 293,389 90,645 DSU awards 33,481 24,345 2021 ESPP 9,604 13,554 Weighted average number of common shares outstanding, diluted 56,406,500 56,179,606 Basic earnings per common share $ 0.47 $ 0.66 Diluted earnings per common share $ 0.46 $ 0.65
Schedule of average shares excluded from computation of diluted earnings per common share	Average shares that were excluded from the computation of diluted earnings per common share because their effect would have been anti-dilutive are summarized in the table below for the periods presented: Three Months Ended March 31, 2024 2023 Anti-dilutive common stock equivalents Options 20,386 22,806 PSU awards 108,671 265,459 Total anti-dilutive common stock equivalents 129,057 288,265

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2024
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Alternative [Abstract]
Accumulated other comprehensive income (loss)	The following tables present changes in AOCI by component, net of tax, for the periods indicated (dollars in thousands) : Three Months Ended March 31, 2024 2023 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Unrealized/Unrecognized gains (losses) on debt securities Balance at beginning of period $ (282,688) $ 80,579 $ (202,109) $ (352,878) $ 100,585 $ (252,293) Unrealized holding gains (losses) on debt securities available for sale, net (7,947) 2,266 (5,681) 30,693 (8,749) 21,944 Amounts reclassified from AOCI, net 6,802 (1,939) 4,863 (4) 1 (3) Amortization of unrecognized losses on securities transferred to held to maturity 1,411 (402) 1,009 1,693 (483) 1,210 Balance at end of period (282,422) 80,504 (201,918) (320,496) 91,354 (229,142) Unrealized gains (losses) on cash flow hedges Balance at beginning of period (23,348) 6,654 (16,694) (29,350) 8,365 (20,985) Unrealized holding gains (losses) on cash flow hedges, net (7,318) 2,086 (5,232) 4,264 (1,214) 3,050 Amounts reclassified from AOCI, net 2,313 (659) 1,654 1,809 (516) 1,293 Balance at end of period (28,353) 8,081 (20,272) (23,277) 6,635 (16,642) Total AOCI $ (310,775) $ 88,585 $ (222,190) $ (343,773) $ 97,989 $ (245,784)

OPERATING SEGMENTS AND RELATE_2

OPERATING SEGMENTS AND RELATED INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Summary of information relating to operating segments	Following is a summary of selected financial information for Busey’s operating segments. The “other” category included in the tables below consists of the parent company, First Busey Risk Management, Inc. until its dissolution on December 18, 2023, and the elimination of intercompany transactions (dollars in thousands) : Goodwill Total Assets As of As of March 31, December 31, March 31, December 31, Operating segment Banking $ 294,773 $ 294,773 $ 11,722,919 $ 12,125,298 Wealth Management 14,108 14,108 107,251 103,147 FirsTech 8,992 8,992 50,643 51,600 Other — — 6,645 3,370 Consolidated total $ 317,873 $ 317,873 $ 11,887,458 $ 12,283,415 Three Months Ended March 31, 2024 2023 Net interest income Banking $ 79,533 $ 89,890 FirsTech 13 13 Other (3,779) (4,046) Total net interest income $ 75,767 $ 85,857 Noninterest income Banking $ 13,472 $ 12,421 Wealth Management 15,712 14,926 FirsTech 5,971 5,674 Other (155) (1,173) Total noninterest income $ 35,000 $ 31,848 Noninterest expense Banking $ 52,387 $ 54,651 Wealth Management 9,136 8,534 FirsTech 5,866 5,739 Other 3,380 1,479 Total noninterest expense $ 70,769 $ 70,403 Income before income taxes Banking $ 35,580 $ 46,707 Wealth Management 6,576 6,392 FirsTech 118 (52) Other (7,314) (6,698) Total income before income taxes $ 34,960 $ 46,349 Net income Banking $ 26,492 $ 36,835 Wealth Management 4,998 4,858 FirsTech 86 (38) Other (5,351) (4,869) Total net income $ 26,225 $ 36,786

SIGNIFICANT ACCOUNTING POLICI_3

SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands			3 Months Ended
	Apr. 01, 2024 USD ($) shares	Jan. 01, 2024 USD ($)	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total assets			$ 11,887,458		$ 12,283,415
Number of operating segments | segment			3
Number of reportable segments | segment			3
Retained earnings decrease			$ (248,412)		$ (237,197)
Decrease in other assets			1,613	$ (2,119)
Decrease in other liabilities			10,055	2,000
Increase in deferred tax assets			$ 0	$ 1,617
Merchants And Manufacturers Bank Corporation | Subsequent Event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Business combination consideration, number of shares (in shares) | shares	1,429,304
Payments to acquire business	$ 12,200
Accounting Standards Update 2023-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings decrease		$ 1,400
Decrease in other assets		2,400
Decrease in other liabilities		500
Increase in deferred tax assets		$ 500

DEBT SECURITIES - Schedule of A

DEBT SECURITIES - Schedule of Amortized Cost, Unrealized Gains and Losses, and Fair Values of Securities Classified as AFS and HTM (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt securities available for sale
Amortized Cost	$ 2,146,276	$ 2,334,630
Gross unrealized gains	108	186
Gross unrealized losses	(248,312)	(247,245)
Fair Value	1,898,072	2,087,571
Debt securities held to maturity
Amortized Cost	862,218	872,628
Gross unrealized gains	0	0
Gross unrealized losses	(149,187)	(142,231)
Fair Value	713,031	730,397
U.S. Treasury securities
Debt securities available for sale
Amortized Cost	749	16,031
Gross unrealized gains	0	0
Gross unrealized losses	(7)	(85)
Fair Value	742	15,946
Obligations of U.S. government corporations and agencies
Debt securities available for sale
Amortized Cost	5,777	5,889
Gross unrealized gains	1	1
Gross unrealized losses	(35)	(58)
Fair Value	5,743	5,832
Obligations of states and political subdivisions
Debt securities available for sale
Amortized Cost	168,997	190,819
Gross unrealized gains	20	52
Gross unrealized losses	(18,091)	(18,026)
Fair Value	150,926	172,845
Asset-backed securities
Debt securities available for sale
Amortized Cost	462,082	470,046
Gross unrealized gains	0	0
Gross unrealized losses	(384)	(1,823)
Fair Value	461,698	468,223
Commercial mortgage-backed securities
Debt securities available for sale
Amortized Cost	108,006	119,044
Gross unrealized gains	0	0
Gross unrealized losses	(15,443)	(15,535)
Fair Value	92,563	103,509
Debt securities held to maturity
Amortized Cost	424,946	428,526
Gross unrealized gains	0	0
Gross unrealized losses	(74,590)	(71,000)
Fair Value	350,356	357,526
Residential mortgage-backed securities
Debt securities available for sale
Amortized Cost	1,223,453	1,306,854
Gross unrealized gains	2	5
Gross unrealized losses	(201,722)	(195,547)
Fair Value	1,021,733	1,111,312
Debt securities held to maturity
Amortized Cost	437,272	444,102
Gross unrealized gains	0	0
Gross unrealized losses	(74,597)	(71,231)
Fair Value	362,675	372,871
Corporate debt securities
Debt securities available for sale
Amortized Cost	177,212	225,947
Gross unrealized gains	85	128
Gross unrealized losses	(12,630)	(16,171)
Fair Value	$ 164,667	$ 209,904

DEBT SECURITIES - Maturity of D

DEBT SECURITIES - Maturity of Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized Cost
Due in one year or less	$ 262,012
Due after one year through five years	752,610
Due after five years through ten years	529,926
Due after ten years	601,728
Amortized Cost	2,146,276	$ 2,334,630
Fair Value
Due in one year or less	222,566
Due after one year through five years	666,718
Due after five years through ten years	469,029
Due after ten years	539,759
Fair Value	1,898,072	2,087,571
Amortized Cost
Due in one year or less	104,797
Due after one year through five years	263,376
Due after five years through ten years	241,243
Due after ten years	252,802
Amortized Cost	862,218	872,628
Fair Value
Due in one year or less	88,589
Due after one year through five years	216,744
Due after five years through ten years	198,562
Due after ten years	209,136
Fair Value	$ 713,031	$ 730,397

DEBT SECURITIES - Schedule of R

DEBT SECURITIES - Schedule of Realized Gains and Losses on Debt Securities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Realized gains and losses on debt securities
Gross gains on debt securities	$ 1	$ 10
Gross (losses) on debt securities	(6,803)	(6)
Realized net gains (losses) on debt securities	(6,802)	$ 4
Debt securities available for sale	108,200
Pre-tax loss on debt securities	6,800
Gain on sale of mortgage servicing rights, before tax	7,500
Mortgage servicing rights sold	$ 923,500

DEBT SECURITIES - Narrative (De

DEBT SECURITIES - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Asset Pledged as Collateral
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities, carrying amount	$ 787.5	$ 837.4

DEBT SECURITIES - Debt securiti

DEBT SECURITIES - Debt securities in an unrealized loss position (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value
Less than 12 months	$ 13,002	$ 13,033
12 months or more	1,661,232	2,049,784
Total	1,674,234	2,062,817
Unrealized Losses
Less than 12 months	(171)	(65)
Unrealized Losses	(248,141)	(247,180)
Total	(248,312)	(247,245)
Fair Value
12 months or more	713,031	730,397
Total	713,031	730,397
Unrealized Losses
12 months or more	(149,187)	(142,231)
Total	(149,187)	(142,231)
U.S. Treasury securities
Fair Value
Less than 12 months	0	0
12 months or more	742	15,946
Total	742	15,946
Unrealized Losses
Less than 12 months	0	0
Unrealized Losses	(7)	(85)
Total	(7)	(85)
Obligations of U.S. government corporations and agencies
Fair Value
Less than 12 months	0	0
12 months or more	5,629	5,709
Total	5,629	5,709
Unrealized Losses
Less than 12 months	0	0
Unrealized Losses	(35)	(58)
Total	(35)	(58)
Obligations of states and political subdivisions
Fair Value
Less than 12 months	8,524	11,442
12 months or more	134,945	146,797
Total	143,469	158,239
Unrealized Losses
Less than 12 months	(68)	(54)
Unrealized Losses	(18,023)	(17,972)
Total	(18,091)	(18,026)
Asset-backed securities
Fair Value
Less than 12 months	0	0
12 months or more	253,231	468,223
Total	253,231	468,223
Unrealized Losses
Less than 12 months	0	0
Unrealized Losses	(384)	(1,823)
Total	(384)	(1,823)
Commercial mortgage-backed securities
Fair Value
Less than 12 months	0	0
12 months or more	92,563	103,509
Total	92,563	103,509
Unrealized Losses
Less than 12 months	0	0
Unrealized Losses	(15,443)	(15,535)
Total	(15,443)	(15,535)
Fair Value
12 months or more	350,356	357,526
Total	350,356	357,526
Unrealized Losses
12 months or more	(74,590)	(71,000)
Total	(74,590)	(71,000)
Residential mortgage-backed securities
Fair Value
Less than 12 months	165	141
12 months or more	1,021,383	1,110,906
Total	1,021,548	1,111,047
Unrealized Losses
Less than 12 months	(1)	(1)
Unrealized Losses	(201,721)	(195,546)
Total	(201,722)	(195,547)
Fair Value
12 months or more	362,675	372,871
Total	362,675	372,871
Unrealized Losses
12 months or more	(74,597)	(71,231)
Total	(74,597)	(71,231)
Corporate debt securities
Fair Value
Less than 12 months	4,313	1,450
12 months or more	152,739	198,694
Total	157,052	200,144
Unrealized Losses
Less than 12 months	(102)	(10)
Unrealized Losses	(12,528)	(16,161)
Total	$ (12,630)	$ (16,171)

DEBT SECURITIES - Additional In

DEBT SECURITIES - Additional Information on Debt Securities In Unrealized or Unrecognized Loss Position (Details) $ in Thousands	Mar. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Available for Sale
Debt securities with gross unrealized or unrecognized losses, fair value | $	$ 1,674,234	$ 2,062,817
Gross unrealized or unrecognized losses on debt securities | $	$ 248,312	$ 247,245
Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses	14.80%	12%
Count of debt securities | security	708	835
Count of debt securities in an unrealized or unrecognized loss position | security	654	779
Held to Maturity
Debt securities with gross unrealized or unrecognized losses, fair value | $	$ 713,031	$ 730,397
Gross unrealized or unrecognized losses on debt securities | $	$ 149,187	$ 142,231
Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses	20.90%	19.50%
Count of debt securities | security	55	55
Count of debt securities in an unrealized or unrecognized loss position | security	55	55
Total
Debt securities with gross unrealized or unrecognized losses, fair value | $	$ 2,387,265	$ 2,793,214
Gross unrealized or unrecognized losses on debt securities | $	$ 397,499	$ 389,476
Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses	16.70%	13.90%
Count of debt securities | security	763	890
Count of debt securities in an unrealized or unrecognized loss position | security	709	834

PORTFOLIO LOANS - Distribution

PORTFOLIO LOANS - Distribution of portfolio loans (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	$ 7,588,077	$ 7,651,034
ACL	(91,562)	(91,740)	$ (91,727)	$ (91,608)
Portfolio loans, net	7,496,515	7,559,294
Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	5,606,241	5,635,048
ACL	(64,425)	(61,884)
C&I and other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	1,828,711	1,835,994
ACL	(26,207)	(21,256)	(24,276)	(23,860)
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	3,331,670	3,337,337
ACL	(33,505)	(35,465)	(34,421)	(38,299)
Real estate construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	445,860	461,717
ACL	(4,713)	(5,163)	(5,159)	(6,457)
Total retail loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	1,981,836	2,015,986
ACL	(27,137)	(29,856)
Retail real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	1,708,663	1,720,455
ACL	(24,281)	(26,298)	(24,255)	(18,193)
Retail other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	273,173	295,531
ACL	$ (2,856)	$ (3,558)	$ (3,616)	$ (4,799)

PORTFOLIO LOANS - Narrative (De

PORTFOLIO LOANS - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net deferred loan origination (fees) costs	$ 13,400,000		$ 13,500,000
Net accretable purchase accounting adjustments	(4,300,000)		(4,500,000)
Gross interest income that would have been recorded if impaired loans had been current	300,000	$ 400,000
Amount of interest collected and recognized on a cash basis	0	0
Collateral dependent loans secured by real estate or business assets	14,200,000		$ 6,100,000
Loans in the process of foreclosure	900,000
Retail real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans purchased	0	$ 0
Commercial real estate | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Limit where loans are processed through an expedited underwriting process	1,000,000
Total commercial loans | Watch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Limit above which loans are annually reviewed	1,000,000
Total commercial loans | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Limit above which loans are annually reviewed	$ 350,000

PORTFOLIO LOANS - Schedule of f

PORTFOLIO LOANS - Schedule of financial instruments owned and pledged as collateral (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial Instruments Owned and Pledged as Collateral [Line Items]
Portfolio loans, net	$ 7,496,515	$ 7,559,294
Asset Pledged as Collateral
Financial Instruments Owned and Pledged as Collateral [Line Items]
Portfolio loans, net	5,546,456	5,588,395
FHLB
Financial Instruments Owned and Pledged as Collateral [Line Items]
Portfolio loans, net	4,821,485	4,865,481
Federal Reserve Bank
Financial Instruments Owned and Pledged as Collateral [Line Items]
Portfolio loans, net	$ 724,971	$ 722,914

PORTFOLIO LOANS - Summary of ri

PORTFOLIO LOANS - Summary of risk grades segregated by category of portfolio loans (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	$ 7,588,077	$ 7,651,034
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	6,663,672	6,736,067
Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	722,802	747,122
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	96,308	96,057
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	87,830	64,347
Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	17,465	7,441
Total commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	5,606,241	5,635,048
Total commercial loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	4,698,629	4,737,796
Total commercial loans | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	713,431	735,978
Total commercial loans | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	95,386	95,033
Total commercial loans | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	85,141	62,552
Total commercial loans | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	13,654	3,689
C&I and other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	1,828,711	1,835,994
C&I and other commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	1,491,166	1,462,755
C&I and other commercial | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	243,635	296,416
C&I and other commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	37,711	46,488
C&I and other commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	42,853	27,733
C&I and other commercial | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	13,346	2,602
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	3,331,670	3,337,337
Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	2,797,374	2,827,030
Commercial real estate | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	447,313	431,427
Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	49,932	48,545
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	36,987	29,492
Commercial real estate | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	64	843
Real estate construction
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	445,860	461,717
Real estate construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	410,089	448,011
Real estate construction | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	22,483	8,135
Real estate construction | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	7,743	0
Real estate construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	5,301	5,327
Real estate construction | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	244	244
Total retail loans
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	1,981,836	2,015,986
Total retail loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	1,965,043	1,998,271
Total retail loans | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	9,371	11,144
Total retail loans | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	922	1,024
Total retail loans | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	2,689	1,795
Total retail loans | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	3,811	3,752
Retail real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	1,708,663	1,720,455
Retail real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	1,692,013	1,702,897
Retail real estate | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	9,371	11,144
Retail real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	922	1,024
Retail real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	2,689	1,795
Retail real estate | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	3,668	3,595
Retail other
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	273,173	295,531
Retail other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	273,030	295,374
Retail other | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	0	0
Retail other | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	0	0
Retail other | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	0	0
Retail other | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Commercial loans	$ 143	$ 157

PORTFOLIO LOANS - Risk grades o

PORTFOLIO LOANS - Risk grades of portfolio loans, further sorted by origination year (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	$ 324,894	$ 1,520,323
2024 / 2023, charge-off	0	289
2023 / 2022	1,348,600	1,785,798
2023 /2022, charge-off	5,133	76
2022 / 2021	1,727,027	1,552,072
2022 / 2021, charge-off	0	592
2021 / 2020	1,472,816	705,335
2021 / 2020, charge-off	23	34
2020 / 2019	679,982	468,659
2020 / 2019, charge-off	0	391
Prior	1,034,094	660,624
Prior, charge-off	304	3,036
Revolving Loans	1,000,664	958,223
Revolving Loans, charge-off	0	0
Total	7,588,077	7,651,034
Total, gross write-offs	5,460	4,418
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,663,672	6,736,067
Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Total	722,802	747,122
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	96,308	96,057
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	87,830	64,347
Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
Total	17,465	7,441
C&I and other commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	106,803	394,854
2024 / 2023, charge-off	0	284
2023 / 2022	326,698	295,539
2023 /2022, charge-off	5,130	0
2022 / 2021	273,965	184,527
2022 / 2021, charge-off	0	420
2021 / 2020	174,810	96,530
2021 / 2020, charge-off	0	0
2020 / 2019	90,655	47,510
2020 / 2019, charge-off	0	316
Prior	188,858	169,911
Prior, charge-off	88	1,409
Revolving Loans	666,922	647,123
Revolving Loans, charge-off	0	0
Total	1,828,711	1,835,994
Total, gross write-offs	5,218	2,429
C&I and other commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	92,898	306,578
2023 / 2022	261,771	220,847
2022 / 2021	214,944	159,130
2021 / 2020	156,831	71,025
2020 / 2019	66,161	35,927
Prior	154,099	143,078
Revolving Loans	544,462	526,170
Total	1,491,166	1,462,755
C&I and other commercial | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	4,869	78,603
2023 / 2022	58,913	65,703
2022 / 2021	49,671	21,421
2021 / 2020	14,389	23,919
2020 / 2019	23,226	7,035
Prior	27,759	21,293
Revolving Loans	64,808	78,442
Total	243,635	296,416
C&I and other commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	665	792
2023 / 2022	239	8,224
2022 / 2021	7,964	2,917
2021 / 2020	2,654	1,076
2020 / 2019	677	686
Prior	3,264	3,274
Revolving Loans	22,248	29,519
Total	37,711	46,488
C&I and other commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	8,371	8,715
2023 / 2022	5,700	765
2022 / 2021	1,386	942
2021 / 2020	819	426
2020 / 2019	525	3,734
Prior	2,348	1,859
Revolving Loans	23,704	11,292
Total	42,853	27,733
C&I and other commercial | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	166
2023 / 2022	75	0
2022 / 2021	0	117
2021 / 2020	117	84
2020 / 2019	66	128
Prior	1,388	407
Revolving Loans	11,700	1,700
Total	13,346	2,602
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	137,962	578,595
2024 / 2023, charge-off	0	0
2023 / 2022	507,916	882,350
2023 /2022, charge-off	0	0
2022 / 2021	897,297	844,293
2022 / 2021, charge-off	0	0
2021 / 2020	820,234	441,134
2021 / 2020, charge-off	0	0
2020 / 2019	425,881	344,373
2020 / 2019, charge-off	0	0
Prior	521,338	226,537
Prior, charge-off	96	953
Revolving Loans	21,042	20,055
Revolving Loans, charge-off	0	0
Total	3,331,670	3,337,337
Total, gross write-offs	96	953
Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	77,146	395,644
2023 / 2022	362,541	824,506
2022 / 2021	845,621	720,052
2021 / 2020	676,837	399,195
2020 / 2019	384,545	271,078
Prior	433,216	199,662
Revolving Loans	17,468	16,893
Total	2,797,374	2,827,030
Commercial real estate | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	58,049	166,795
2023 / 2022	131,059	47,070
2022 / 2021	35,873	92,848
2021 / 2020	111,998	34,010
2020 / 2019	32,964	68,196
Prior	73,846	19,396
Revolving Loans	3,524	3,112
Total	447,313	431,427
Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	1,405	14,313
2023 / 2022	8,646	10,507
2022 / 2021	13,126	12,446
2021 / 2020	12,578	4,968
2020 / 2019	5,015	3,297
Prior	9,162	3,014
Revolving Loans	0	0
Total	49,932	48,545
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	1,362	1,796
2023 / 2022	5,626	188
2022 / 2021	2,677	18,862
2021 / 2020	18,821	2,938
2020 / 2019	3,337	1,802
Prior	5,114	3,856
Revolving Loans	50	50
Total	36,987	29,492
Commercial real estate | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	47
2023 / 2022	44	79
2022 / 2021	0	85
2021 / 2020	0	23
2020 / 2019	20	0
Prior	0	609
Revolving Loans	0	0
Total	64	843
Real estate construction
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	58,333	213,138
2024 / 2023, charge-off	0	0
2023 / 2022	194,159	132,868
2023 /2022, charge-off	0	0
2022 / 2021	90,355	85,593
2022 / 2021, charge-off	0	0
2021 / 2020	75,737	2,938
2021 / 2020, charge-off	0	0
2020 / 2019	2,778	1,364
2020 / 2019, charge-off	0	0
Prior	3,576	3,178
Prior, charge-off	0	0
Revolving Loans	20,922	22,638
Revolving Loans, charge-off	0	0
Total	445,860	461,717
Total, gross write-offs	0	0
Real estate construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	58,333	204,952
2023 / 2022	177,437	128,462
2022 / 2021	72,325	85,086
2021 / 2020	75,282	2,616
2020 / 2019	2,458	1,323
Prior	3,332	2,934
Revolving Loans	20,922	22,638
Total	410,089	448,011
Real estate construction | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	2,859
2023 / 2022	3,678	4,406
2022 / 2021	18,030	507
2021 / 2020	455	322
2020 / 2019	320	41
Prior	0	0
Revolving Loans	0	0
Total	22,483	8,135
Real estate construction | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0
2023 / 2022	7,743
2022 / 2021	0
2021 / 2020	0
2020 / 2019	0
Prior	0
Revolving Loans	0
Total	7,743	0
Real estate construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	5,327
2023 / 2022	5,301	0
2022 / 2021	0	0
2021 / 2020	0	0
2020 / 2019	0	0
Prior	0	0
Revolving Loans	0	0
Total	5,301	5,327
Real estate construction | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	0
2023 / 2022	0	0
2022 / 2021	0	0
2021 / 2020	0	0
2020 / 2019	0	0
Prior	244	244
Revolving Loans	0	0
Total	244	244
Retail real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	20,338	244,851
2024 / 2023, charge-off	0	0
2023 / 2022	241,821	382,017
2023 /2022, charge-off	0	5
2022 / 2021	381,426	414,578
2022 / 2021, charge-off	0	0
2021 / 2020	381,781	158,032
2021 / 2020, charge-off	0	29
2020 / 2019	155,230	70,815
2020 / 2019, charge-off	0	72
Prior	316,775	260,142
Prior, charge-off	52	301
Revolving Loans	211,292	190,020
Revolving Loans, charge-off	0	0
Total	1,708,663	1,720,455
Total, gross write-offs	52	407
Retail real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	19,533	243,400
2023 / 2022	240,662	376,922
2022 / 2021	376,623	411,723
2021 / 2020	378,955	156,762
2020 / 2019	153,995	70,099
Prior	313,080	256,571
Revolving Loans	209,165	187,420
Total	1,692,013	1,702,897
Retail real estate | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	805	1,096
2023 / 2022	832	4,137
2022 / 2021	2,873	2,442
2021 / 2020	2,242	954
2020 / 2019	937	536
Prior	401	234
Revolving Loans	1,281	1,745
Total	9,371	11,144
Retail real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	286
2023 / 2022	191	358
2022 / 2021	354	0
2021 / 2020	0	0
2020 / 2019	0	0
Prior	377	380
Revolving Loans	0	0
Total	922	1,024
Retail real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	69
2023 / 2022	136	72
2022 / 2021	1,049	292
2021 / 2020	519	49
2020 / 2019	45	80
Prior	935	997
Revolving Loans	5	236
Total	2,689	1,795
Retail real estate | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	0
2023 / 2022	0	528
2022 / 2021	527	121
2021 / 2020	65	267
2020 / 2019	253	100
Prior	1,982	1,960
Revolving Loans	841	619
Total	3,668	3,595
Retail other
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	1,458	88,885
2024 / 2023, charge-off	0	5
2023 / 2022	78,006	93,024
2023 /2022, charge-off	3	71
2022 / 2021	83,984	23,081
2022 / 2021, charge-off	0	172
2021 / 2020	20,254	6,701
2021 / 2020, charge-off	23	5
2020 / 2019	5,438	4,597
2020 / 2019, charge-off	0	3
Prior	3,547	856
Prior, charge-off	68	373
Revolving Loans	80,486	78,387
Revolving Loans, charge-off	0	0
Total	273,173	295,531
Total, gross write-offs	94	629
Retail other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	1,458	88,885
2023 / 2022	78,006	92,931
2022 / 2021	83,891	23,019
2021 / 2020	20,205	6,701
2020 / 2019	5,438	4,597
Prior	3,546	854
Revolving Loans	80,486	78,387
Total	273,030	295,374
Retail other | Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Retail other | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Retail other | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Retail other | Substandard Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2024 / 2023	0	0
2023 / 2022	0	93
2022 / 2021	93	62
2021 / 2020	49	0
2020 / 2019	0	0
Prior	1	2
Revolving Loans	0	0
Total	$ 143	$ 157

PORTFOLIO LOANS -Summary of por

PORTFOLIO LOANS -Summary of portfolio loans that are past due and still accruing or on a non-accrual status (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Commercial loans	$ 7,588,077	$ 7,651,034
90 days past due and still accruing	88	375
Non-accrual Loans	17,465	7,441
30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	6,616	4,443
60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	825	1,336
Past due and non-accrual commercial loans
Financing Receivable, Past Due [Line Items]
Commercial loans	5,606,241	5,635,048
90 days past due and still accruing	0	0
Non-accrual Loans	13,654	3,689
Past due and non-accrual commercial loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	3,217	776
Past due and non-accrual commercial loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	338	214
C&I and other commercial
Financing Receivable, Past Due [Line Items]
Commercial loans	1,828,711	1,835,994
90 days past due and still accruing	0	0
Non-accrual Loans	13,346	2,602
C&I and other commercial | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	43	0
C&I and other commercial | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	0	214
Commercial real estate
Financing Receivable, Past Due [Line Items]
Commercial loans	3,331,670	3,337,337
90 days past due and still accruing	0	0
Non-accrual Loans	64	843
Commercial real estate | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	3,174	752
Commercial real estate | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	338	0
Real estate construction
Financing Receivable, Past Due [Line Items]
Commercial loans	445,860	461,717
90 days past due and still accruing	0	0
Non-accrual Loans	244	244
Real estate construction | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	0	24
Real estate construction | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	0	0
Past due and non-accrual retail loans
Financing Receivable, Past Due [Line Items]
Commercial loans	1,981,836	2,015,986
90 days past due and still accruing	88	375
Non-accrual Loans	3,811	3,752
Past due and non-accrual retail loans | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	3,399	3,667
Past due and non-accrual retail loans | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	487	1,122
Retail real estate
Financing Receivable, Past Due [Line Items]
Commercial loans	1,708,663	1,720,455
90 days past due and still accruing	77	366
Non-accrual Loans	3,668	3,595
Retail real estate | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	2,869	2,781
Retail real estate | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	385	927
Retail other
Financing Receivable, Past Due [Line Items]
Commercial loans	273,173	295,531
90 days past due and still accruing	11	9
Non-accrual Loans	143	157
Retail other | 30 to 59 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	530	886
Retail other | 60 to 89 days past due and still accruing
Financing Receivable, Past Due [Line Items]
Commercial loans	$ 102	$ 195

PORTFOLIO LOANS - Schedule of l

PORTFOLIO LOANS - Schedule of loan modifications made to borrowers experiencing financial difficulty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Payment Deferral
Loans identified as impaired
Amortized cost basis	$ 10,000	$ 489
% of total class of financing receivable	0.10%	0%
Payment Deferral | C&I and other commercial
Loans identified as impaired
Amortized cost basis	$ 10,000	$ 489
% of total class of financing receivable	0.50%	0%
Payment Deferral | Commercial real estate
Loans identified as impaired
Amortized cost basis	$ 0	$ 0
% of total class of financing receivable	0%	0%
Term Extension
Loans identified as impaired
Amortized cost basis	$ 18,860	$ 37,853
% of total class of financing receivable	0.20%	0.50%
Term Extension | C&I and other commercial
Loans identified as impaired
Amortized cost basis	$ 17,155	$ 25,155
% of total class of financing receivable	0.90%	1.30%
Term Extension | Commercial real estate
Loans identified as impaired
Amortized cost basis	$ 1,705	$ 12,698
% of total class of financing receivable	0.10%	0.40%

PORTFOLIO LOANS - Summary of th

PORTFOLIO LOANS - Summary of the financial effect of modifications (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Loans identified as impaired
Weighted Average Term Extension	17 months 18 days	8 months
C&I and other commercial
Loans identified as impaired
Weighted Average Term Extension	19 months 3 days	9 months 3 days
Commercial real estate
Loans identified as impaired
Weighted Average Term Extension	2 months	5 months 24 days

PORTFOLIO LOANS - Schedule of p

PORTFOLIO LOANS - Schedule of payment status of modified loans (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Loans identified as impaired
Non-accrual	$ 10,000
Current
Loans identified as impaired
Amortized cost of modified loans	29,951
30-89 Days
Loans identified as impaired
Amortized cost of modified loans	0
90+ Days
Loans identified as impaired
Amortized cost of modified loans	0
C&I and other commercial
Loans identified as impaired
Non-accrual	10,000
C&I and other commercial | Current
Loans identified as impaired
Amortized cost of modified loans	21,641
C&I and other commercial | 30-89 Days
Loans identified as impaired
Amortized cost of modified loans	0
C&I and other commercial | 90+ Days
Loans identified as impaired
Amortized cost of modified loans	0
Commercial real estate
Loans identified as impaired
Non-accrual	0
Commercial real estate | Current
Loans identified as impaired
Amortized cost of modified loans	3,009
Commercial real estate | 30-89 Days
Loans identified as impaired
Amortized cost of modified loans	0
Commercial real estate | 90+ Days
Loans identified as impaired
Amortized cost of modified loans	0
Real estate construction
Loans identified as impaired
Non-accrual	0
Real estate construction | Current
Loans identified as impaired
Amortized cost of modified loans	5,301
Real estate construction | 30-89 Days
Loans identified as impaired
Amortized cost of modified loans	0
Real estate construction | 90+ Days
Loans identified as impaired
Amortized cost of modified loans	$ 0

PORTFOLIO LOANS - Schedule of d

PORTFOLIO LOANS - Schedule of details of impaired loans, segregated by category (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance	$ 20,585		$ 10,096
Recorded investment with no allowance	2,258		1,256
Recorded investment with allowance	10,945		1,895
Total recorded investment	13,203		3,151
Related Allowance	7,523		895
Average Recorded Investment	9,460	$ 9,948
Total commercial loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance	20,372		9,883
Recorded investment with no allowance	2,197		1,195
Recorded investment with allowance	10,920		1,870
Total recorded investment	13,117		3,065
Related Allowance	7,498		870
Average Recorded Investment	9,171	9,158
C&I and other commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance	20,372		7,283
Recorded investment with no allowance	2,197		585
Recorded investment with allowance	10,920		1,785
Total recorded investment	13,117		2,370
Related Allowance	7,498		785
Average Recorded Investment	6,553	5,244
Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance	0		2,600
Recorded investment with no allowance	0		610
Recorded investment with allowance	0		85
Total recorded investment	0		695
Related Allowance	0		85
Average Recorded Investment	2,618	3,865
Real estate construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance			0
Recorded investment with no allowance			0
Recorded investment with allowance			0
Total recorded investment			0
Related Allowance			0
Average Recorded Investment		49
Total retail loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance	213		213
Recorded investment with no allowance	61		61
Recorded investment with allowance	25		25
Total recorded investment	86		86
Related Allowance	25		25
Average Recorded Investment	289	790
Retail real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Unpaid Principal Balance	213		213
Recorded investment with no allowance	61		61
Recorded investment with allowance	25		25
Total recorded investment	86		86
Related Allowance	25		$ 25
Average Recorded Investment	$ 289	$ 790

PORTFOLIO LOANS - Schedule of a

PORTFOLIO LOANS - Schedule of activity on the allowance for loan losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Activity in the allowance for loan losses
ACL beginning balance	$ 91,740	$ 91,608
Provision for credit losses	5,038	953
Charged-off	(5,460)	(1,181)
Recoveries	244	347
ACL ending balance	91,562	91,727
C&I and other commercial
Activity in the allowance for loan losses
ACL beginning balance	21,256	23,860
Provision for credit losses	10,125	695
Charged-off	(5,218)	(400)
Recoveries	44	121
ACL ending balance	26,207	24,276
Commercial real estate
Activity in the allowance for loan losses
ACL beginning balance	35,465	38,299
Provision for credit losses	(1,864)	(3,359)
Charged-off	(96)	(539)
Recoveries	0	20
ACL ending balance	33,505	34,421
Real estate construction
Activity in the allowance for loan losses
ACL beginning balance	5,163	6,457
Provision for credit losses	(491)	(1,329)
Charged-off	0	0
Recoveries	41	31
ACL ending balance	4,713	5,159
Retail real estate
Activity in the allowance for loan losses
ACL beginning balance	26,298	18,193
Provision for credit losses	(2,093)	5,948
Charged-off	(52)	(5)
Recoveries	128	119
ACL ending balance	24,281	24,255
Retail other
Activity in the allowance for loan losses
ACL beginning balance	3,558	4,799
Provision for credit losses	(639)	(1,002)
Charged-off	(94)	(237)
Recoveries	31	56
ACL ending balance	$ 2,856	$ 3,616

PORTFOLIO LOANS - Schedule of_2

PORTFOLIO LOANS - Schedule of allowance for loan losses and recorded investments in portfolio loans, by category (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Portfolio Loans
Collectively Evaluated for Impairment	$ 7,574,874	$ 7,647,883
Individually Evaluated for Impairment	13,203	3,151
Total	7,588,077	7,651,034
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	84,039	90,845
Individually Evaluated for Impairment	7,523	895
Total	91,562	91,740	$ 91,727	$ 91,608
Total commercial loans
Portfolio Loans
Collectively Evaluated for Impairment	5,593,124	5,631,983
Individually Evaluated for Impairment	13,117	3,065
Total	5,606,241	5,635,048
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	56,927	61,014
Individually Evaluated for Impairment	7,498	870
Total	64,425	61,884
C&I and other commercial
Portfolio Loans
Collectively Evaluated for Impairment	1,815,594	1,833,624
Individually Evaluated for Impairment	13,117	2,370
Total	1,828,711	1,835,994
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	18,709	20,471
Individually Evaluated for Impairment	7,498	785
Total	26,207	21,256	24,276	23,860
Commercial real estate
Portfolio Loans
Collectively Evaluated for Impairment	3,331,670	3,336,642
Individually Evaluated for Impairment	0	695
Total	3,331,670	3,337,337
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	33,505	35,380
Individually Evaluated for Impairment	0	85
Total	33,505	35,465	34,421	38,299
Real estate construction
Portfolio Loans
Collectively Evaluated for Impairment	445,860	461,717
Individually Evaluated for Impairment	0	0
Total	445,860	461,717
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	4,713	5,163
Individually Evaluated for Impairment	0	0
Total	4,713	5,163	5,159	6,457
Total retail loans
Portfolio Loans
Collectively Evaluated for Impairment	1,981,750	2,015,900
Individually Evaluated for Impairment	86	86
Total	1,981,836	2,015,986
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	27,112	29,831
Individually Evaluated for Impairment	25	25
Total	27,137	29,856
Retail real estate
Portfolio Loans
Collectively Evaluated for Impairment	1,708,577	1,720,369
Individually Evaluated for Impairment	86	86
Total	1,708,663	1,720,455
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	24,256	26,273
Individually Evaluated for Impairment	25	25
Total	24,281	26,298	24,255	18,193
Retail other
Portfolio Loans
Collectively Evaluated for Impairment	273,173	295,531
Individually Evaluated for Impairment	0	0
Total	273,173	295,531
ACL Attributed to Portfolio Loans
Collectively Evaluated for Impairment	2,856	3,558
Individually Evaluated for Impairment	0	0
Total	$ 2,856	$ 3,558	$ 3,616	$ 4,799

LEASES - Summary of lease-relat

LEASES - Summary of lease-related balances (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Right of use assets	$ 10,590	$ 11,027
Lease liabilities	$ 10,896	$ 11,308
Weighted average remaining lease term	8 years 3 months 3 days	8 years 4 months 20 days
Weighted average discount rate	3.61%	3.59%

LEASES - Schedule of lease cost

LEASES - Schedule of lease costs and other lease information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lease costs
Operating lease costs	$ 535	$ 628
Variable lease costs	14	5
Short-term lease costs	13	6
Total lease cost	562	639
Cash flows related to leases
Operating lease cash flows – Fixed payments	507	570
Operating lease cash flows – Liability reduction	411	479
Right of use assets obtained during the period in exchange for operating lease liabilities	$ 0	$ 4

LEASES - Schedule of future und

LEASES - Schedule of future undiscounted lease payments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Rent commitments
Remainder of 2024	$ 1,515
2025	1,768
2026	1,443
2027	1,277
2028	1,255
2029	1,278
Thereafter	4,200
Total undiscounted cash flows	12,736
Less: Amounts representing interest	1,840
Present value of net future minimum lease payments	$ 10,896	$ 11,308

LEASES - Summary of revenue rec

LEASES - Summary of revenue recorded in connection with leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Rental income	$ 202	$ 191

DEPOSITS - Schedule of composit

DEPOSITS - Schedule of composition of deposits (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Deposits [Abstract]
Noninterest-bearing demand deposits	$ 2,784,338	$ 2,834,655
Interest-bearing transaction deposits	2,397,937	2,717,139
Saving deposits and money market deposits	3,200,738	2,920,088
Time deposits	1,577,178	1,819,274
Total deposits	9,960,191	10,291,156
Brokered savings deposits and money market deposits	6,001	6,001
Brokered time deposits	0	285
Aggregate amount of time deposits with a minimum denomination of $100,000	898,433	1,072,189
Aggregate amount of time deposits with a minimum denomination that meets or exceeds the FDIC insurance limit of $250,000	$ 326,794	$ 386,286

DEPOSITS - Schedule of maturiti

DEPOSITS - Schedule of maturities of time deposits (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Time deposits by schedule of maturities
Remainder of 2024	$ 1,371,431
2025	156,304
2026	22,905
2027	13,209
2028	10,150
2029	2,743
Thereafter	436
Time deposits	$ 1,577,178	$ 1,819,274

BORROWINGS - Schedule of distri

BORROWINGS - Schedule of distribution of securities sold under agreements to repurchase and short-term borrowings and weighted average interest rates (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
Securities sold under agreements to repurchase	$ 147,175	$ 187,396
Weighted average rate for securities sold under agreements to repurchase	2.96%	3.26%

BORROWINGS - Term Loan (Details

BORROWINGS - Term Loan (Details) - USD ($)			3 Months Ended
	Apr. 30, 2022	May 28, 2021	Mar. 31, 2024
Revolving Credit Facility
Short-Term Debt [Line Items]
Issuance of debt		$ 40,000,000
Balance outstanding			$ 0
Term Loan
Short-Term Debt [Line Items]
Issuance of debt		$ 60,000,000
Repayment of term loan			$ 30,000,000
Term loan carried interest rate			7.13%
One-month LIBOR rate | Term Loan
Short-Term Debt [Line Items]
Floating interest rate margin (as a percent)		1.75%
SOFR-indexed interest rate | Term Loan
Short-Term Debt [Line Items]
Floating interest rate margin (as a percent)	1.80%

BORROWINGS - Schedule of Short-

BORROWINGS - Schedule of Short-term Borrowings (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Short-Term Debt [Line Items]
Total short-term debt	$ 0	$ 12,000,000
Federal funds purchased	0	0
Term Loan, current portion due within 12 months
Short-Term Debt [Line Items]
Total short-term debt	$ 0	$ 12,000,000
Minimum
Short-Term Debt [Line Items]
Short-term borrowings, mature period	1 day
Maximum
Short-Term Debt [Line Items]
Short-term borrowings, mature period	90 days

BORROWINGS - Summary of Long-te

BORROWINGS - Summary of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 18,000
Term Loan
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 18,000

BORROWINGS - Subordinated Notes

BORROWINGS - Subordinated Notes (Details) - Subordinated Debt - USD ($) $ in Millions	Jun. 02, 2022	Jun. 01, 2020
5.25% notes maturing June 1, 2030
Debt Instrument [Line Items]
Issuance of debt		$ 125
Interest rate		5.25%
Duration of fixed interest rate		5 years
Floating interest rate margin (as a percent)		5.11%
5.000% notes due 2032
Debt Instrument [Line Items]
Issuance of debt	$ 100
Fixed to floating interest rate	5%
Percentage of principal amount of notes	100%
5.000% notes due 2032 | SOFR
Debt Instrument [Line Items]
Floating interest rate margin (as a percent)	2.52%

BORROWINGS - Schedule of unamor

BORROWINGS - Schedule of unamortized debt issuance cost (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total unamortized debt issuance costs	$ 1,900	$ 2,118
Subordinated notes issued in 2020 | Subordinated Debt
Debt Instrument [Line Items]
Total unamortized debt issuance costs	610	735
Subordinated notes issued in 2022 | Subordinated Debt
Debt Instrument [Line Items]
Total unamortized debt issuance costs	$ 1,290	$ 1,383

REGULATORY CAPITAL - Capital Am

REGULATORY CAPITAL - Capital Amounts and Ratios (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount
Actual	$ 1,166,919	$ 1,155,973
Minimum Capital Requirement	390,433	397,331
Minimum To Be Well Capitalized	$ 563,958	$ 573,923
Common Equity Tier 1 Capital to Risk Weighted Assets, Ratio
Actual	13.45%	13.09%
Minimum Capital Requirement	4.50%	4.50%
Minimum To Be Well Capitalized	6.50%	6.50%
Tier 1 Capital to Risk Weighted Assets, Amount
Actual	$ 1,240,919	$ 1,229,973
Minimum Capital Requirement	520,577	529,775
Minimum To Be Well Capitalized	$ 694,103	$ 706,367
Tier 1 Capital to Risk Weighted Assets, Ratio
Actual	14.30%	13.93%
Minimum Capital Requirement	6%	6%
Minimum To Be Well Capitalized	8%	8%
Total Capital to Risk Weighted Assets, Amount
Actual	$ 1,557,137	$ 1,540,318
Minimum Capital Requirement	694,103	706,367
Minimum To Be Well Capitalized	$ 867,628	$ 882,958
Total Capital to Risk Weighted Assets, Ratio
Actual	17.95%	17.44%
Minimum Capital Requirement	8%	8%
Minimum To Be Well Capitalized	10%	10%
Leverage Ratio of Tier 1 Capital to Average Assets, Amount
Actual	$ 1,240,919	$ 1,229,973
Minimum Capital Requirement	$ 474,678	$ 488,315
Leverage Ratio of Tier 1 Capital to Average Assets, Ratio
Actual	10.46%	10.08%
Minimum Capital Requirement	4%	4%
Busey Bank
Common Equity Tier 1 Capital to Risk Weighted Assets, Amount
Actual	$ 1,365,033	$ 1,362,962
Minimum Capital Requirement	389,113	396,128
Minimum To Be Well Capitalized	$ 562,052	$ 572,185
Common Equity Tier 1 Capital to Risk Weighted Assets, Ratio
Actual	15.79%	15.48%
Minimum Capital Requirement	4.50%	4.50%
Minimum To Be Well Capitalized	6.50%	6.50%
Tier 1 Capital to Risk Weighted Assets, Amount
Actual	$ 1,365,033	$ 1,362,962
Minimum Capital Requirement	518,817	528,171
Minimum To Be Well Capitalized	$ 691,756	$ 704,228
Tier 1 Capital to Risk Weighted Assets, Ratio
Actual	15.79%	15.48%
Minimum Capital Requirement	6%	6%
Minimum To Be Well Capitalized	8%	8%
Total Capital to Risk Weighted Assets, Amount
Actual	$ 1,456,250	$ 1,448,307
Minimum Capital Requirement	691,756	704,228
Minimum To Be Well Capitalized	$ 864,695	$ 880,285
Total Capital to Risk Weighted Assets, Ratio
Actual	16.84%	16.45%
Minimum Capital Requirement	8%	8%
Minimum To Be Well Capitalized	10%	10%
Leverage Ratio of Tier 1 Capital to Average Assets, Amount
Actual	$ 1,365,033	$ 1,362,962
Minimum Capital Requirement	473,422	487,103
Minimum To Be Well Capitalized	$ 591,777	$ 608,879
Leverage Ratio of Tier 1 Capital to Average Assets, Ratio
Actual	11.53%	11.19%
Minimum Capital Requirement	4%	4%
Minimum To Be Well Capitalized	5%	5%

TAX CREDIT AND OTHER INVESTME_3

TAX CREDIT AND OTHER INVESTMENTS IN UNCONSOLIDATED ENTITIES - Schedule of Impact of the Busey's other asset investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	$ 120,878	$ 127,068
Tax effects of investments in tax-advantaged projects
Income tax credits and other tax benefits	4,101
Amortization of investments in tax-advantaged projects	3,647
Funded investments | Other assets
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	64,516	68,516
Unfunded investments | Other assets
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated entities	56,362	58,552
Unfunded investments | Other liabilities
Schedule of Equity Method Investments [Line Items]
Unfunded investment obligations	$ 56,362	$ 58,552

STOCK-BASED COMPENSATION - Summ

STOCK-BASED COMPENSATION - Summary of changes in the Company's stock option awards (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Shares
Outstanding at beginning of year (in shares)	21,266
Forfeited (in shares)	(880)
Outstanding at end of year (in shares)	20,386	21,266
Exercisable at end of year (in shares)	20,386
Weighted- Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 23.53
Forfeited (in dollars per share)	23.53
Outstanding at end of year (in dollars per share)	23.53	$ 23.53
Exercisable at end of year (in dollars per share)	$ 23.53
Weighted- Average Remaining Contractual Life
Weighted-average remaining contractual life, options outstanding	2 years 7 months 17 days	2 years 10 months 17 days
Weighted-average remaining contractual life, exercisable at end of year	2 years 7 months 17 days

STOCK-BASED COMPENSATION - 2020

STOCK-BASED COMPENSATION - 2020 Equity Plan (Details) - shares	Apr. 14, 2023	Mar. 31, 2024
Amended 2020 Equity Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Increase in the number of shares authorized for issuance (in shares)	1,350,000
2020 Equity Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Remaining shares available for issuance (in shares)		1,333,769

STOCK-BASED COMPENSATION - RSU,

STOCK-BASED COMPENSATION - RSU, PSU, and DSU Narrative (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
	Mar. 20, 2024	Mar. 31, 2024	Jun. 30, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Period over which cost will be recognized		2 years 8 months 12 days	2 years 4 months 24 days
RSU Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares of common stock per award (in shares)		1
Granted (in shares)		189,179
RSU Awards | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Requisite service periods		1 year
RSU Awards | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Requisite service periods		5 years
PSU Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares of common stock per award (in shares)		1
Granted (in shares)		189,208
DSU awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares of common stock per award (in shares)		1
Granted (in shares)		35,847
Vesting period		1 year
Settlement period		30 days
Market Based Performance Stock Units | 2020 Equity Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	94,604
Grant date fair value of the award	$ 2.2
Market Based Performance Stock Units | 2020 Equity Plan | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	0%
Market Based Performance Stock Units | 2020 Equity Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	151,366
Vesting percentage	160%
Performance Based Performance Stock Units | 2020 Equity Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	94,604
Grant date fair value of the award	$ 2.2
Performance Based Performance Stock Units | 2020 Equity Plan | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage	0%
Performance Based Performance Stock Units | 2020 Equity Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	151,366
Vesting percentage	160%
Members of management, including the Vice-Chairman of the Board | RSU Awards | 2020 Equity Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	189,179
Grant date fair value of the award	$ 4.4
Vesting percentage	100%
Members of management, including the Vice-Chairman of the Board | RSU Awards | 2020 Equity Plan | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Period over which cost will be recognized	1 year
Members of management, including the Vice-Chairman of the Board | RSU Awards | 2020 Equity Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Period over which cost will be recognized	5 years
Directors and Advisory Directors | DSU awards | 2020 Equity Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Granted (in shares)	35,847
Grant date fair value of the award	$ 0.8
Period over which cost will be recognized	1 year
Vesting percentage	100%

STOCK-BASED COMPENSATION - Su_2

STOCK-BASED COMPENSATION - Summary of changes in the Company's RSU, PSU, and DSU awards (Details)	3 Months Ended
	Mar. 31, 2024 $ / shares shares
RSU Awards
Shares
Non-vested at beginning of period (in shares) | shares	1,041,444
Granted (in shares) | shares	189,179
Dividend equivalents earned (in shares) | shares	10,219
Vested (in shares) | shares	(7,681)
Forfeited (in shares) | shares	(5,347)
Non-vested at end of period (in shares) | shares	1,227,814
Weighted- Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 22.05
Granted (in dollars per share) | $ / shares	23.35
Dividend equivalents earned (in dollars per share) | $ / shares	24.46
Vested (in dollars per share) | $ / shares	23.23
Forfeited (in dollars per share) | $ / shares	23.38
Non-vested at end of period (in dollars per share) | $ / shares	$ 22.25
PSU Awards
Shares
Non-vested at beginning of period (in shares) | shares	341,700
Granted (in shares) | shares	189,208
Dividend equivalents earned (in shares) | shares	4,264
Vested (in shares) | shares	(4,264)
Forfeited (in shares) | shares	(1,754)
Non-vested at end of period (in shares) | shares	529,154
Weighted- Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 22.67
Granted (in dollars per share) | $ / shares	23.35
Dividend equivalents earned (in dollars per share) | $ / shares	22.95
Vested (in dollars per share) | $ / shares	22.95
Forfeited (in dollars per share) | $ / shares	22.76
Non-vested at end of period (in dollars per share) | $ / shares	$ 22.91
DSU awards
Shares
Non-vested at beginning of period (in shares) | shares	43,026
Granted (in shares) | shares	35,847
Dividend equivalents earned (in shares) | shares	1,836
Vested (in shares) | shares	(44,862)
Non-vested at end of period (in shares) | shares	35,847
Vested and outstanding at end of period (in shares) | shares	189,000
Weighted- Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 20.41
Granted (in dollars per share) | $ / shares	23.35
Dividend equivalents earned (in dollars per share) | $ / shares	24.46
Vested (in dollars per share) | $ / shares	20.57
Non-vested at end of period (in dollars per share) | $ / shares	23.35
Vested and outstanding at end of period (in dollars per share) | $ / shares	$ 22.82

STOCK-BASED COMPENSATION - 2021

STOCK-BASED COMPENSATION - 2021 Employee Stock Purchase Plan and Stock-based Compensation Expense (Details) - USD ($)		3 Months Ended
	Jul. 01, 2021	Mar. 31, 2024	Mar. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock option compensation expense		$ 2,403,000	$ 1,669,000
Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock option compensation expense		0	$ 0
Unrecognized stock option compensation expense		$ 0
2021 ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Discount through voluntary payroll deductions	15%
Remaining shares available for issuance (in shares)	600,000	429,074

STOCK-BASED COMPENSATION - Sche

STOCK-BASED COMPENSATION - Schedule of Stock-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 2,403	$ 1,669
RSU Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	894	1,020
PSU Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	1,210	360
DSU awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	215	196
2021 ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 84	$ 93

STOCK-BASED COMPENSATION - Sc_2

STOCK-BASED COMPENSATION - Schedule of Unamortized stock-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total unamortized stock-based compensation	$ 19,814		$ 10,639
Weighted average period over which expense is to be recognized	2 years 8 months 12 days	2 years 4 months 24 days
RSU Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total unamortized stock-based compensation	$ 10,259		6,842
PSU Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total unamortized stock-based compensation	8,743		3,607
DSU awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total unamortized stock-based compensation	$ 812		$ 190

OUTSTANDING COMMITMENTS AND C_3

OUTSTANDING COMMITMENTS AND CONTINGENT LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Credit Commitments and Contingencies
Total commitments	$ 2,165,588	$ 2,176,496
Commitments to extend credit
Credit Commitments and Contingencies
Total commitments	2,118,621	2,132,500
Standby letters of credit
Credit Commitments and Contingencies
Total commitments	$ 46,967	$ 43,996

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of financial instruments owned and pledged as collateral (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Interest Rate Swap
Derivative [Line Items]
Cash pledged to secure obligations	$ 34,210	$ 34,210
Interest Rate Contract
Derivative [Line Items]
Cash pledged to secure obligations	$ 24,860	$ 19,280

DERIVATIVE FINANCIAL INSTRUME_4

DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Interest Rate Swap | Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	$ 300,000
Interest Rate Swap | Designated as Hedging Instrument | SOFR
Derivative [Line Items]
Notional amount	100,000
Interest Rate Swap | Not Designated as Hedging Instrument
Derivative [Line Items]
Variable rate, commercial loans that are supported by the interest rate swap contracts	678,300	$ 663,100
Interest Rate Swap | Cash Flow Hedging | Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	450,000	350,000
Debt Swap | Cash Flow Hedging
Derivative [Line Items]
Notional amount	50,000	$ 50,000
Debt Swap | Cash Flow Hedging | Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	$ 50,000

DERIVATIVE FINANCIAL INSTRUME_5

DERIVATIVE FINANCIAL INSTRUMENTS - Summary of the interest-rate swaps designated as cash flow hedges (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Interest Rate Swap
Balances carried in AOCI
Unrealized gains (losses) on cash flow hedges, net of tax	$ 0	$ 0
Cash Flow Hedging | Interest Rate Swap
Balances carried in AOCI
Unrealized gains (losses) on cash flow hedges, net of tax	(20,272)		$ (16,694)
Cash Flow Hedging | Interest Rate Swap | Other assets
Gross aggregate fair value of the swaps
Gross aggregate fair value of swap assets	1,178		1,293
Cash Flow Hedging | Interest Rate Swap | Other liabilities
Gross aggregate fair value of the swaps
Gross aggregate fair value of swap liabilities	30,303		25,411
Cash Flow Hedging | Debt Swap
Derivative [Line Items]
Notional amount	$ 50,000		$ 50,000
Weighted average fixed pay/receive rates	1.79%		1.79%
Weighted average variable interest rates	5.62%		5.61%
Weighted average maturity	5 months 15 days		8 months 15 days
Cash Flow Hedging | Loan Swap
Derivative [Line Items]
Notional amount	$ 300,000		$ 300,000
Weighted average fixed pay/receive rates	4.81%		4.81%
Weighted average variable interest rates	8.50%		8.50%
Weighted average maturity	4 years 10 months 6 days		5 years 1 month 6 days
Cash Flow Hedging | SOFR Loan Swap
Derivative [Line Items]
Notional amount	$ 100,000		$ 0
Weighted average fixed pay/receive rates	3.72%		0%
Weighted average maturity	4 years 11 months 4 days

DERIVATIVE FINANCIAL INSTRUME_6

DERIVATIVE FINANCIAL INSTRUMENTS - Reclassification of unrealized gains and losses from OCI (Details) - Interest Rate Swap - Cash Flow Hedging $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Derivative [Line Items]
Net unrealized gains (losses) in OCI expected to be recognized in net interest income	$ (469)
Interest Income
Derivative [Line Items]
Net unrealized gains (losses) in OCI expected to be recognized in net interest income	(952)
Interest Expense
Derivative [Line Items]
Net unrealized gains (losses) in OCI expected to be recognized in net interest income	$ 483

DERIVATIVE FINANCIAL INSTRUME_7

DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of interest income (expense) recorded on swap transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
(Increase) decrease in interest expense on swap transactions	$ (49,966)	$ (25,248)
Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Increase (decrease) in interest income on swap transactions	(2,796)	(2,192)
(Increase) decrease in interest expense on swap transactions	483	383
Net increase (decrease) in net interest income on swap transactions	$ (2,313)	$ (1,809)

DERIVATIVE FINANCIAL INSTRUME_8

DERIVATIVE FINANCIAL INSTRUMENTS - Net Gains (Losses) Recorded in Accumulated Other Comprehensive Income (Loss) (Details) - Cash Flow Hedging - Interest Rate Contract - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Net gain (loss) recognized in OCI, net of tax	$ (5,232)	$ 3,050
(Gain) loss reclassified from OCI to interest income, net of tax	1,999	1,567
(Gain) loss reclassified from OCI to interest expense, net of tax	(345)	(274)
Net change in unrealized gains (losses) on cash flow hedges, net of tax	$ (3,578)	$ 4,343

DERIVATIVE FINANCIAL INSTRUME_9

DERIVATIVE FINANCIAL INSTRUMENTS - Interest Rate Swaps Not Designated as Hedges (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Interest Rate Swap
Derivative Asset
Notional Amount	$ 678,334	$ 663,136
Fair Value	34,420	28,664
Derivative Liability
Notional Amount	678,334	663,136
Fair Value	34,420	28,664
Interest rate swaps – pay floating, receive fixed
Derivative Asset
Notional Amount	71,472	177,883
Fair Value	868	2,375
Derivative Liability
Notional Amount	606,862	485,253
Fair Value	33,552	26,289
Interest rate swaps – pay fixed, receive floating
Derivative Asset
Notional Amount	606,862	485,253
Fair Value	33,552	26,289
Derivative Liability
Notional Amount	71,472	177,883
Fair Value	$ 868	$ 2,375

DERIVATIVE FINANCIAL INSTRUM_10

DERIVATIVE FINANCIAL INSTRUMENTS - Interest Rate Swaps Recorded in Noninterest Expense (Details) - Interest Rate Swap - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Net change in fair value of interest rate swaps	$ 0	$ 0
Noninterest expense
Derivative [Line Items]
Gain (loss), pay floating, receive fixed	5,480	(7,667)
Gain (loss), pay fixed, receive floating	$ (5,480)	$ 7,667

DERIVATIVE FINANCIAL INSTRUM_11

DERIVATIVE FINANCIAL INSTRUMENTS - Risk Participation Agreement (Details) $ in Thousands	Mar. 31, 2024 USD ($) agreement	Dec. 31, 2023 USD ($) agreement
Risk participation agreements purchased
Derivative [Line Items]
Number of risk participation agreements | agreement	4	3
Notional amount	$ 35,097	$ 34,251
Fair value	$ 9	$ 15
Risk participation agreements sold
Derivative [Line Items]
Number of risk participation agreements | agreement	1	1
Notional amount	$ 20,001	$ 20,001
Fair value	$ 0	$ 0

DERIVATIVE FINANCIAL INSTRUM_12

DERIVATIVE FINANCIAL INSTRUMENTS - Mortgage Banking Derivatives (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Mortgage banking derivative assets
Derivative asset, statement of financial position [Extensible Enumeration]	Other assets	Other assets
Mortgage banking derivative liabilities
Derivative liability, statement of financial position [Extensible Enumeration]	Other liabilities	Other liabilities
Interest rate lock commitments
Mortgage banking derivative assets
Notional Amount	$ 9,123	$ 3,477
Fair value recorded in other assets	133	25
Mortgage banking derivative liabilities
Notional Amount	268	1,615
Fair value recorded in other liabilities	3	10
Forward sales commitments
Mortgage banking derivative assets
Notional Amount	2,772	1,761
Fair value recorded in other assets	9	11
Mortgage banking derivative liabilities
Notional Amount	6,619	5,216
Fair value recorded in other liabilities	51	47
Mortgage banking derivative assets | Designated as Hedging Instrument
Mortgage banking derivative assets
Notional Amount	11,895	5,238
Fair value recorded in other assets	142	36
Mortgage banking derivative liabilities
Notional Amount	6,887	6,831
Fair value recorded in other liabilities	$ 54	$ 57

DERIVATIVE FINANCIAL INSTRUM_13

DERIVATIVE FINANCIAL INSTRUMENTS - Net Gains (Losses) Relating to Derivative Instruments (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest rate lock commitments | Mortgage revenue
Derivative [Line Items]
Net change in fair value of interest rate swaps	$ 267	$ 37
Interest rate lock commitments | Other expense
Derivative [Line Items]
Net change in fair value of interest rate swaps	5	0
Forward sales commitments | Mortgage revenue
Derivative [Line Items]
Net change in fair value of interest rate swaps	9	(54)
Forward sales commitments | Other expense
Derivative [Line Items]
Net change in fair value of interest rate swaps	$ 51	$ 0

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of financial assets and financial liabilities measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	$ 1,898,072	$ 2,087,571
Equity securities	9,790	9,812
U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	742	15,946
Obligations of U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	5,743	5,832
Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	150,926	172,845
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	461,698	468,223
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	92,563	103,509
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1,021,733	1,111,312
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	164,667	209,904
Fair Value, Recurring | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	35,749	30,008
Fair Value, Recurring | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	64,777	54,132
Fair Value, Recurring | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	742	15,946
Fair Value, Recurring | Obligations of U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	5,743	5,832
Fair Value, Recurring | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	150,926	172,845
Fair Value, Recurring | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	461,698	468,223
Fair Value, Recurring | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	92,563	103,509
Fair Value, Recurring | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1,021,733	1,111,312
Fair Value, Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	164,667	209,904
Fair Value, Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	9,790	9,812
Fair Value, Recurring | Level 1 Inputs | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Fair Value, Recurring | Level 1 Inputs | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Fair Value, Recurring | Level 1 Inputs | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Obligations of U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 1 Inputs | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	448
Fair Value, Recurring | Level 2 Inputs | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	35,740	29,993
Fair Value, Recurring | Level 2 Inputs | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	64,777	54,132
Fair Value, Recurring | Level 2 Inputs | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	742	15,946
Fair Value, Recurring | Level 2 Inputs | Obligations of U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	5,743	5,832
Fair Value, Recurring | Level 2 Inputs | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	150,926	172,845
Fair Value, Recurring | Level 2 Inputs | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	461,698	468,223
Fair Value, Recurring | Level 2 Inputs | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	92,563	103,509
Fair Value, Recurring | Level 2 Inputs | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1,021,733	1,111,312
Fair Value, Recurring | Level 2 Inputs | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	164,667	209,904
Fair Value, Recurring | Level 2 Inputs | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	9,790	9,364
Fair Value, Recurring | Level 3 Inputs | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	9	15
Fair Value, Recurring | Level 3 Inputs | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Fair Value, Recurring | Level 3 Inputs | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Obligations of U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair Value, Recurring | Level 3 Inputs | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Sch_2

FAIR VALUE MEASUREMENTS - Schedule of assets and liabilities measured at fair value on a non-recurring basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually, net of related allowance	$ 13,203	$ 3,151
Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually, net of related allowance	3,422	1,000
Bank property held for sale with impairment	4,238	4,286
Level 1 Inputs | Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually, net of related allowance	0	0
Bank property held for sale with impairment	0	0
Level 2 Inputs | Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually, net of related allowance	0	0
Bank property held for sale with impairment	0	0
Level 3 Inputs | Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually, net of related allowance	3,422	1,000
Bank property held for sale with impairment	$ 4,238	$ 4,286

FAIR VALUE MEASUREMENTS - Sch_3

FAIR VALUE MEASUREMENTS - Schedule of quantitative information about Level 3 fair value measurements (Details) $ in Thousands	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value
Loans evaluated individually, net of related allowance	$ 13,203	$ 3,151
Fair Value, Nonrecurring
Fair Value
Loans evaluated individually, net of related allowance	3,422	1,000
Bank property held for sale with impairment	4,238	4,286
Fair Value, Nonrecurring | Level 3 Inputs
Fair Value
Loans evaluated individually, net of related allowance	3,422	1,000
Bank property held for sale with impairment	4,238	4,286
Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral
Fair Value
Loans evaluated individually, net of related allowance	3,422	1,000
Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral or real estate listing price
Fair Value
Bank property held for sale with impairment	$ 4,238	$ 4,286
Measurement Input, Comparability Adjustment | Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral | Minimum
Range (Weighted Average)
Loans evaluated individually, net of related allowance	(0.250)	(0.412)
Measurement Input, Comparability Adjustment | Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral | Maximum
Range (Weighted Average)
Loans evaluated individually, net of related allowance	(1)	(1)
Measurement Input, Comparability Adjustment | Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral | Weighted Average
Range (Weighted Average)
Loans evaluated individually, net of related allowance	(0.687)	(0.472)
Measurement Input, Comparability Adjustment | Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral or real estate listing price | Minimum
Range (Weighted Average)
Bank property held for sale with impairment	(0.090)	(0.062)
Measurement Input, Comparability Adjustment | Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral or real estate listing price | Maximum
Range (Weighted Average)
Bank property held for sale with impairment	(0.649)	(0.649)
Measurement Input, Comparability Adjustment | Fair Value, Nonrecurring | Level 3 Inputs | Appraisal of collateral or real estate listing price | Weighted Average
Range (Weighted Average)
Bank property held for sale with impairment	(0.391)	(0.384)

FAIR VALUE MEASUREMENTS - Sch_4

FAIR VALUE MEASUREMENTS - Schedule of estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial assets
Debt securities held to maturity	$ 713,031	$ 730,397
Portfolio loans, net	7,496,515	7,559,294
Financial liabilities
Short-term borrowings	0	12,000
Junior subordinated debt owed to unconsolidated trusts	72,040	71,993
Level 1 Inputs | Carrying Amount
Financial assets
Cash and cash equivalents	591,071	719,581
Level 1 Inputs | Fair Value
Financial assets
Cash and cash equivalents	591,071	719,581
Level 2 Inputs | Carrying Amount
Financial assets
Debt securities held to maturity	862,218	872,628
Loans held for sale	6,827	2,379
Accrued interest receivable	46,530	45,288
Financial liabilities
Time deposits	1,577,178	1,819,274
Securities sold under agreements to repurchase	147,175	187,396
Short-term borrowings	0	12,000
Long-term debt	0	18,000
Junior subordinated debt owed to unconsolidated trusts	72,040	71,993
Accrued interest payable	26,707	28,418
Level 2 Inputs | Fair Value
Financial assets
Debt securities held to maturity	713,031	730,397
Loans held for sale	6,834	2,401
Accrued interest receivable	46,530	45,288
Financial liabilities
Time deposits	1,559,643	1,804,905
Securities sold under agreements to repurchase	147,175	187,396
Short-term borrowings	0	12,034
Long-term debt	0	18,020
Junior subordinated debt owed to unconsolidated trusts	58,776	57,153
Accrued interest payable	26,707	28,418
Level 3 Inputs | Carrying Amount
Financial assets
Portfolio loans, net	7,496,515	7,559,294
Mortgage servicing rights	989	3,289
Other servicing rights	1,573	1,597
Level 3 Inputs | Fair Value
Financial assets
Portfolio loans, net	7,293,871	7,276,905
Mortgage servicing rights	5,468	18,079
Other servicing rights	2,008	2,062
Level 3 Inputs | Subordinated Debt | Carrying Amount
Financial liabilities
Long-term debt	223,100	222,882
Level 3 Inputs | Subordinated Debt | Fair Value
Financial liabilities
Long-term debt	$ 204,750	$ 200,000

EARNINGS PER COMMON SHARE - Sch

EARNINGS PER COMMON SHARE - Schedule of computation of earnings per common share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net income per share calculations for basic and diluted methods
Net income	$ 26,225	$ 36,786
Weighted Average Shares Outstanding
Weighted average number of common shares outstanding, basic (in shares)	55,416,589	55,397,989
Weighted average number of common shares outstanding, diluted (in shares)	56,406,500	56,179,606
Basic earnings per common share (in dollars per share)	$ 0.47	$ 0.66
Diluted earnings per common share (in dollars per share)	$ 0.46	$ 0.65
Warrants
Weighted Average Shares Outstanding
Dilutive effect of common stock equivalents (in shares)	0	1,296
RSU Awards
Weighted Average Shares Outstanding
Dilutive effect of common stock equivalents (in shares)	653,437	651,777
PSU Awards
Weighted Average Shares Outstanding
Dilutive effect of common stock equivalents (in shares)	293,389	90,645
DSU awards
Weighted Average Shares Outstanding
Dilutive effect of common stock equivalents (in shares)	33,481	24,345
2021 ESPP
Weighted Average Shares Outstanding
Dilutive effect of common stock equivalents (in shares)	9,604	13,554

EARNINGS PER COMMON SHARE - S_2

EARNINGS PER COMMON SHARE - Schedule of average shares excluded from computation of diluted earnings per common share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive common stock equivalents (in shares)	129,057	288,265
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive common stock equivalents (in shares)	20,386	22,806
PSU Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total anti-dilutive common stock equivalents (in shares)	108,671	265,459

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,271,981	$ 1,145,977
Unrealized/Unrecognized gains (losses) on debt securities
Unrealized holding gains (losses) on debt securities available for sale, net, net of tax	(5,681)	21,944
Amounts reclassified from AOCI, net, net of tax	(4,863)	3
Amortization of unrealized losses on securities transferred to held to maturity, net of tax	(1,009)	(1,210)
Unrealized gains (losses) on cash flow hedges
Unrealized holding gains (losses) on cash flow hedges, net, net of tax	(5,232)	3,050
Amounts reclassified from AOCI, net, net of tax	(1,654)	(1,293)
Ending balance	1,282,651	1,198,558
Total stockholders’ equity	1,282,651	1,198,558
AOCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(218,803)	(273,278)
Unrealized gains (losses) on cash flow hedges
Accumulated other comprehensive income (loss) ending balance period, before tax	(310,775)	(343,773)
Accumulated other comprehensive income (loss) ending balance period, tax effect	88,585	97,989
Ending balance	(222,190)	(245,784)
Total stockholders’ equity	(222,190)	(245,784)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) beginning balance period, before tax	(282,688)	(352,878)
Accumulated other comprehensive income (loss) beginning balance period, tax effect	80,579	100,585
Beginning balance	(202,109)	(252,293)
Unrealized/Unrecognized gains (losses) on debt securities
Unrealized holding gains (losses) on debt securities available for sale, net, before tax	(7,947)	30,693
Unrealized holding gains (losses) on debt securities available for sale, net, tax effect	2,266	(8,749)
Unrealized holding gains (losses) on debt securities available for sale, net, net of tax	(5,681)	21,944
Amounts reclassified from AOCI, net, before tax	6,802	(4)
Amounts reclassified from AOCI, net, tax effect	(1,939)	1
Amounts reclassified from AOCI, net, net of tax	4,863	(3)
Amortization of unrealized losses on securities transferred to held to maturity, before tax	1,411	1,693
Amortization of unrealized losses on securities transferred to held to maturity, tax effect	(402)	(483)
Amortization of unrealized losses on securities transferred to held to maturity, net of tax	1,009	1,210
Unrealized gains (losses) on cash flow hedges
Accumulated other comprehensive income (loss) ending balance period, before tax	(282,422)	(320,496)
Accumulated other comprehensive income (loss) ending balance period, tax effect	80,504	91,354
Ending balance	(201,918)	(229,142)
Total stockholders’ equity	(201,918)	(229,142)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) beginning balance period, before tax	(23,348)	(29,350)
Accumulated other comprehensive income (loss) beginning balance period, tax effect	6,654	8,365
Beginning balance	(16,694)	(20,985)
Unrealized gains (losses) on cash flow hedges
Unrealized holding gains (losses) on cash flow hedges, net, before tax	(7,318)	4,264
Unrealized holding gains (losses) on cash flow hedges, net, tax effect	2,086	(1,214)
Unrealized holding gains (losses) on cash flow hedges, net, net of tax	(5,232)	3,050
Amounts reclassified from AOCI, net, before tax	2,313	1,809
Amounts reclassified from AOCI, net, tax effect	(659)	(516)
Amounts reclassified from AOCI, net, net of tax	1,654	1,293
Accumulated other comprehensive income (loss) ending balance period, before tax	(28,353)	(23,277)
Accumulated other comprehensive income (loss) ending balance period, tax effect	8,081	6,635
Ending balance	(20,272)	(16,642)
Total stockholders’ equity	$ (20,272)	$ (16,642)

OPERATING SEGMENTS AND RELATE_3

OPERATING SEGMENTS AND RELATED INFORMATION - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 center segment
Segment Reporting [Abstract]
Number of reportable segments	3
Number of operating segments	3
Number of banking centers consolidated | center	58

OPERATING SEGMENTS AND RELATE_4

OPERATING SEGMENTS AND RELATED INFORMATION - Summary of information relating to operating segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Goodwill	$ 317,873		$ 317,873
Total Assets	11,887,458		12,283,415
Net interest income	75,767	$ 85,857
Noninterest income	35,000	31,848
Noninterest expense	70,769	70,403
Income before income taxes	34,960	46,349
Net income	26,225	36,786
Operating segment | Banking
Segment Reporting Information [Line Items]
Goodwill	294,773		294,773
Total Assets	11,722,919		12,125,298
Net interest income	79,533	89,890
Noninterest income	13,472	12,421
Noninterest expense	52,387	54,651
Income before income taxes	35,580	46,707
Net income	26,492	36,835
Operating segment | Wealth Management
Segment Reporting Information [Line Items]
Goodwill	14,108		14,108
Total Assets	107,251		103,147
Noninterest income	15,712	14,926
Noninterest expense	9,136	8,534
Income before income taxes	6,576	6,392
Net income	4,998	4,858
Operating segment | FirsTech
Segment Reporting Information [Line Items]
Goodwill	8,992		8,992
Total Assets	50,643		51,600
Net interest income	13	13
Noninterest income	5,971	5,674
Noninterest expense	5,866	5,739
Income before income taxes	118	(52)
Net income	86	(38)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Goodwill	0		0
Total Assets	6,645		$ 3,370
Net interest income	(3,779)	(4,046)
Noninterest income	(155)	(1,173)
Noninterest expense	3,380	1,479
Income before income taxes	(7,314)	(6,698)
Net income	$ (5,351)	$ (4,869)

ACQUISITION (Details)

ACQUISITION (Details) - Merchants And Manufacturers Bank Corporation - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Apr. 01, 2024	Mar. 31, 2024
Business Acquisition, Contingent Consideration [Line Items]
Pre-tax acquisition expenses		$ 0.3
Subsequent Event
Business Acquisition, Contingent Consideration [Line Items]
Per share cash consideration entitled, Cash Election (in dollars per share)	$ 117.74
Shares received in business combination, Cash Election (in shares)	5.7294
Consideration transferred per share in cash, Mixed Election	$ 34.55
Consideration transferred per share in shares, Mixed Election	4.0481
Business combination consideration, number of shares (in shares)	1,429,304
Payments to acquire business	$ 12.2
Consideration transferred per share in cash, Share Election	$ 5.3966
Consideration transferred per share in shares, Share Election	5.4668
Cash consideration received (in usd per share)	$ 117.74
Fractional shares, payment rate (in usd per share)	$ 23.32