First Busey (BUSE) 10-Q 6 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 06, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2021
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		54,280,379
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Central Index Key	0000314489
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets
Cash and due from banks	$ 110,979	$ 118,824
Interest-bearing deposits	293,823	569,713
Total cash and cash equivalents	404,802	688,537
Debt securities available for sale	2,796,955	2,261,187
Equity securities	7,146	5,530
Loans held for sale, at fair value	38,272	42,813
Portfolio loans (net of ACL 2021 $93,943; 2020 $101,048)	6,685,357	6,713,129
Premises and equipment, net	132,669	135,191
Right of use assets	7,333	7,714
Goodwill	311,536	311,536
Other intangible assets, net	49,584	51,985
Cash surrender value of bank owned life insurance	177,466	176,405
Other assets	148,443	150,020
Total assets	10,759,563	10,544,047
Deposits:
Noninterest-bearing	2,859,492	2,552,039
Interest-bearing	6,014,355	6,125,810
Total deposits	8,873,847	8,677,849
Securities sold under agreements to repurchase	210,132	175,614
Short-term borrowings	4,663	4,658
Long-term debt	4,584	4,757
Senior notes, net of unamortized issuance costs	39,843	39,809
Subordinated notes, net of unamortized issuance costs	182,370	182,226
Junior subordinated debt owed to unconsolidated trusts	71,509	71,468
Lease liabilities	7,380	7,757
Other liabilities	99,413	109,840
Total liabilities	9,493,741	9,273,978
Outstanding commitments and contingent liabilities (see Notes 9 and 15)
Stockholders' Equity
Common stock, $.001 par value; 100,000,000 shares authorized; 55,910,733 shares issued	56	56
Additional paid-in capital	1,255,044	1,253,360
Retained earnings	45,897	20,830
Accumulated other comprehensive income (loss)	3,821	33,309
Total stockholders' equity before treasury stock	1,304,818	1,307,555
Treasury stock at cost 2021 1,565,354 shares; 2020 1,506,354 shares	(38,996)	(37,486)
Total stockholders' equity	1,265,822	1,270,069
Total liabilities and stockholders' equity	$ 10,759,563	$ 10,544,047
Common shares outstanding at period end	54,345,379	54,404,379

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
CONSOLIDATED BALANCE SHEETS
Portfolio Loans, allowance for loan losses (in dollars)	$ 93,943	$ 101,048
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	55,910,733	55,910,733
Treasury stock, shares	1,565,354	1,506,354

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest income:
Interest and fees on loans	$ 62,565	$ 72,536
Interest and dividends on investment securities:
Taxable interest income	8,611	9,508
Non-taxable interest income	1,005	1,151
Other interest income	150	1,238
Total interest income	72,331	84,433
Interest expense:
Deposits	3,732	12,227
Federal funds purchased and securities sold under agreements to repurchase	57	408
Short-term borrowings	19	67
Long-term debt	29	423
Senior notes	400	400
Subordinated notes	2,476	731
Junior subordinated debt owed to unconsolidated trusts	725	744
Total interest expense	7,438	15,000
Net interest income	64,893	69,433
Provision for credit losses	(6,796)	17,216
Net interest income after provision for credit losses	71,689	52,217
Non-interest income:
Income on bank owned life insurance	964	1,057
Net gains (losses) on sales of securities	25	1,574
Unrealized gains (losses) recognized on equity securities	1,616	(987)
Other income	1,135	823
Total non-interest income	31,445	27,517
Non-interest expense:
Salaries, wages, and employee benefits	30,384	34,003
Data processing	4,280	4,395
Net occupancy expense of premises	4,563	4,715
Furniture and equipment expenses	2,026	2,449
Professional fees	1,945	1,824
Amortization of intangible assets	2,401	2,557
Interchange expense	1,484	1,169
Other expense	7,416	9,402
Total non-interest expense	54,499	60,514
Income before income taxes	48,635	19,220
Income taxes	10,819	3,856
Net income	$ 37,816	$ 15,364
Basic earnings per common share (in dollars per share)	$ 0.69	$ 0.28
Diluted earnings per common share (in dollars per share)	0.69	0.28
Dividends declared per share of common stock (in dollars per share)	$ 0.23	$ 0.22
Wealth management fees
Non-interest income:
Non-interest income	$ 12,584	$ 11,555
Fees for customer services
Non-interest income:
Non-interest income	8,037	8,361
Remittance processing
Non-interest income:
Non-interest income	4,418	3,753
Mortgage revenue
Non-interest income:
Mortgage revenue	$ 2,666	$ 1,381

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 37,816	$ 15,364
Unrealized gains (losses) on debt securities available for sale:
Net unrealized holding gains (losses) on debt securities available for sale, net of taxes of $11,993 and $(8,589), respectively	(30,079)	21,497
Reclassification adjustment for realized (gains) losses on debt securities available for sale included in net income, net of taxes of $7 and $448, respectively	(18)	(1,108)
Net change in unrealized gains (losses) on debt securities available for sale	(30,097)	20,389
Unrealized gains (losses) on cash flow hedges:
Net unrealized holding gains (losses) on cash flow hedges, net of taxes of $(164) and $892, respectively	410	(2,237)
Reclassification adjustment for realized (gains) losses on cash flow hedges included in net income, net of taxes of $(79) and $4, respectively	199	(11)
Net change in unrealized gains (losses) on cash flow hedges	609	(2,248)
Net change in accumulated other comprehensive income (loss)	(29,488)	18,141
Total comprehensive income	$ 8,328	$ 33,505

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net unrealized holding gains (losses) on debt securities available for sale, net of taxes	$ 11,993	$ (8,589)
Amounts reclassified from accumulated other comprehensive income, Tax Effect	7	448
Tax expense on unrealized holding (losses) gains on cash flow hedges	(164)	892
Tax expense on reclassification adjustment for realized losses (gains) on cash flow hedges included in net income	$ (79)	$ 4

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit).Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings (Accumulated Deficit).	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Cumulative Effect, Period of Adoption, Adjustment	Total
Beginning balance at Dec. 31, 2019	$ 56	$ 1,248,216	$ (15,922)	$ (14,813)	$ 14,960	$ (27,985)	$ (15,922)	$ 1,220,434
Beginning Balance (in shares) at Dec. 31, 2019	54,788,772
Increase (decrease) in shareholders' equity
Net income				15,364				15,364
Other comprehensive income (loss)					18,141			18,141
Repurchase of stock						(9,672)		(9,672)
Repurchase of stock (in shares)	(407,850)
Issuance of treasury stock for employee stock purchase plan		(38)				269		231
Issuance of treasury stock for employee stock purchase plan (in shares)	14,236
Net issuance of treasury stock for restricted/deferred stock unit vesting and related tax		(179)				104		(75)
Net issuance of treasury stock for restricted/deferred stock unit vesting and related tax (in shares)	5,509
Net issuance of treasury stock for stock options exercised, net of shares redeemed and related tax		(10)				10
Net issuance of treasury stock for stock options exercised, net of shares redeemed and related tax (in shares)	541
Cash dividends common stock				(12,055)				(12,055)
Stock dividend equivalents restricted stock units		173		(173)
Stock-based compensation		1,139						1,139
Ending balance at Mar. 31, 2020	$ 56	1,249,301		(27,599)	33,101	(37,274)		1,217,585
Ending Balance (in shares) at Mar. 31, 2020	54,401,208
Beginning balance at Dec. 31, 2020	$ 56	1,253,360		20,830	33,309	(37,486)		1,270,069
Beginning Balance (in shares) at Dec. 31, 2020	54,404,379
Increase (decrease) in shareholders' equity
Net income				37,816				37,816
Other comprehensive income (loss)					(29,488)			(29,488)
Repurchase of stock						(1,510)		(1,510)
Repurchase of stock (in shares)	(59,000)
Cash dividends common stock				(12,513)				(12,513)
Stock dividend equivalents restricted stock units		236		(236)
Stock-based compensation		1,448						1,448
Ending balance at Mar. 31, 2021	$ 56	$ 1,255,044		$ 45,897	$ 3,821	$ (38,996)		$ 1,265,822
Ending Balance (in shares) at Mar. 31, 2021	54,345,379

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
Cash dividends, common stock (in dollars per share)	$ 0.23	$ 0.22
Stock dividends, restricted stock units (in dollars per share)	$ 0.23	$ 0.22

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flows Provided by (Used in) Operating Activities
Net income	$ 37,816	$ 15,364
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for credit losses	(6,796)	17,216
Amortization of intangible assets	2,401	2,557
Amortization of mortgage servicing rights	1,616	1,276
Depreciation and amortization of premises and equipment	2,808	3,165
Net amortization (accretion) of premium (discount) on portfolio loans	(1,947)	(2,487)
Net amortization (accretion) of premium (discount) on investment securities	4,554	1,869
Net amortization (accretion) of premium (discount) on time deposits	(246)	(374)
Net amortization (accretion) of premium (discount) on FHLB advances and other borrowings	214	93
Impairment of mortgage servicing rights	(508)	177
Change in fair value of equity securities, net	(1,616)	987
(Gain) loss on sales of equity securities, net		(18)
(Gain) loss on sales of debt securities, net	(25)	(1,556)
(Gain) loss on sales of loans, net	(3,369)	(3,900)
(Gain) loss on sales of OREO	(1)	1
(Gain) loss on sales of premises and equipment	(134)	37
(Gain) loss on life insurance proceeds		(14)
Provision for deferred income taxes	2,448	1,722
Stock-based and non-cash compensation	1,448	1,139
(Increase) decrease in cash surrender value of bank owned life insurance	(964)	(1,043)
Mortgage loans originated for sale	(91,479)	(182,203)
Proceeds from sales of mortgage loans	98,307	165,008
Net change in operating assets and liabilities:
(Increase) decrease in other assets	260	991
Increase (decrease) in other liabilities	750	(1,194)
Net cash provided by (used in) operating activities	45,537	18,813
Cash Flows Provided by (Used in) Investing Activities
Purchases of equity securities	(998)
Purchases of debt securities available for sale	(789,884)	(273,992)
Proceeds from sales of equity securities	998	29
Proceeds from paydowns and maturities of debt securities available for sale	207,490	158,536
Net (increase) decrease in loans	36,501	(64,338)
Cash paid for premiums on bank-owned life insurance	(97)	(111)
Purchases of premises and equipment	(1,911)	(2,314)
Proceeds from life insurance		274
Proceeds from disposition of premises and equipment	1,759	607
Proceeds from sales of OREO	294	81
Net cash provided by (used in) investing activities	(545,848)	(181,228)
Cash Flows Provided by (Used in) Financing Activities
Net increase (decrease) in deposits	196,244	71,211
Net change in federal funds purchased and securities sold under agreements to repurchase	34,518	(38,241)
Proceeds from other borrowings		20,000
Repayment of other borrowings		(54,000)
Repayment of FHLB advances	(163)	(1,193)
Cash dividends paid	(12,513)	(12,055)
Purchase of treasury stock	(1,510)	(9,672)
Cash paid for withholding taxes on stock-based payments		(75)
Net cash provided by (used in) financing activities	216,576	(24,025)
Net increase (decrease) in cash and cash equivalents	(283,735)	(186,440)
Cash and cash equivalents, beginning of period	688,537	529,288
Cash and cash equivalents, ending of period	404,802	342,848
Cash Payments for:
Interest	1,767	14,391
Income taxes		500
Non-cash Investing and Financing Activities:
OREO acquired in settlement of loans	$ 14	$ 578

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Significant Accounting Policies
Significant Accounting Policies	Note 1: Significant Accounting Policies ​ Nature of Operations ​ First Busey Corporation, a Nevada corporation organized in 1980, is a $10.8 billion financial holding company headquartered in Champaign, Illinois. Our common stock is traded on The Nasdaq Global Select Market under the symbol “BUSE.” ​ The Company operates and reports its business in three segments: Banking, Remittance Processing, and Wealth Management. The Banking operating segment provides a full range of banking services to individual and corporate customers through the Company’s wholly-owned bank subsidiary, Busey Bank, with banking centers in Illinois; the St. Louis, Missouri metropolitan area; southwest Florida; and Indianapolis, Indiana. The Remittance Processing operating segment provides solutions for online bill payments, lockbox, and walk-in payments through the Company’s subsidiary, FirsTech. The Wealth Management operating segment provides a full range of asset management, investment, and fiduciary services to individuals, businesses and foundations, tax preparation, philanthropic advisory services, farms, and brokerage services. ​ 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 our 2020 Annual Report. These interim unaudited consolidated financial statements serve to update our 2020 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. ​ COVID-19 ​ First Busey continues to operate as an essential community resource during these challenging and unprecedented times. Federal bank regulatory agencies, along with their state counterparts, have issued a steady stream of guidance responding to the COVID-19 pandemic and have taken a number of steps to help banks navigate the pandemic and mitigate its impact. ​ The Company remains vigilant, given that negative impacts of COVID-19, such as further margin compression and a deterioration in asset quality, could impact future quarters. ​ As part of the CARES Act, Congress appropriated approximately $349 billion for the creation of the PPP and then authorized a second phase for an additional $310 billion in PPP loans. The program provided payroll assistance for the nation’s nearly 30 million small businesses—and select nonprofits—in the form of government-guaranteed low-interest loans from the SBA. First Busey served as a bridge for the program, actively helping existing and new business clients sign up for this important financial resource. The Company originated a total of new and existing customers. As of March 31, 2021, the Company had received approximately million. Net fee income accretion recognized on these loans in the first quarter of 2021 was ​ On December 27, 2020, the Economic Aid Act extended the authority to make PPP loans through March 31, 2021, and revised certain PPP requirements. On March 30, 2021, the President signed the PPP Extension Act of 2021, which extended the PPP application deadline to May 31, 2021, or until funding is exhausted. As of March 31, 2021, the Company originated a total of new and existing customers. Net fee income accretion recognized on the loans related to this new round of PPP in the first quarter of 2021 was ​ At March 31, 2021, First Busey had $533.4 million in total PPP loans outstanding, with an amortized cost of $522.1 million, representing 3,441 customers. ​ Use of Estimates ​ In preparing the accompanying unaudited consolidated financial statements in conformity with GAAP, the Company’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 investment securities available for sale, fair value of assets acquired and liabilities assumed in business combinations, goodwill, income taxes, and the determination of the ACL. ​ Subsequent Events ​ The Company 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. There were no significant subsequent events for the quarter ended March 31, 2021, through the filing date of these unaudited consolidated financial statements.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2021
Acquisitions
Acquisitions	Note 2: Acquisitions ​ Cummins-American Corp. ​ On January 19, 2021, the Company and CAC, the holding company for GSB, jointly announced the signing of a definitive agreement pursuant to which the Company will acquire CAC and GSB through a merger transaction. The partnership will enhance the Company’s existing deposit, commercial banking, and wealth management presence in the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area. ​ Under the terms of the merger agreement, CAC’s stockholders will have the right to receive 444.4783 shares of First Busey’s common stock and $27,969.67 in cash for each share of common stock of CAC with total consideration to consist of approximately 73% cash and 27% stock. Based upon the closing price of Busey’s common stock of million. The merger agreement provides that the cash consideration to be paid in the merger will be funded with a combination of cash from First Busey and a special dividend to be paid by CAC to its shareholders. Specifically, immediately prior to closing and subject to the completion of all closing conditions, CAC will cause GSB to pay a one-time special cash dividend of million special cash dividend to CAC’s shareholders, which will be used to fund, in part, the cash consideration to be paid to CAC’s shareholders at closing. Further, the cash portion of the merger consideration is subject to downward adjustment in the event that CAC’s consolidated tangible common equity as of the closing date of the first-step merger, and as adjusted in accordance with the merger agreement, is less than million. Specifically, in the event of a CAC tangible common equity shortfall, the cash portion of the merger consideration will be reduced on a dollar-for-dollar basis to the extent of such shortfall. ​ The transaction is expected to close in the second quarter of 2021, subject to customary closing conditions and approval by CAC’s shareholders. Required regulatory approvals have been obtained. It is anticipated GSB will be merged with and into Busey Bank during the third quarter of 2021. At the time of the bank merger, GSB banking centers will become banking centers of Busey Bank. ​ During the three months ended March 31, 2021, First Busey incurred $0.3 million in pre-tax acquisition expenses related to the planned acquisition of CAC, comprised primarily of professional fees.

Securities

Securities	3 Months Ended
	Mar. 31, 2021
Securities
Securities	Note 3: Securities ​ The table below provides the amortized cost, unrealized gains and losses, and fair values of debt securities summarized by major category (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ Fair March 31, 2021: Cost Gains Losses ​ ACL Value U.S. Treasury securities ​ $ 23,514 ​ $ 243 ​ $ — ​ $ — ​ $ 23,757 Obligations of U.S. government corporations and agencies ​ 64,903 ​ 1,720 ​ (45) ​ ​ — ​ 66,578 Obligations of states and political subdivisions ​ 280,150 ​ 8,854 ​ (1,542) ​ ​ — ​ 287,462 Commercial mortgage-backed securities ​ ​ 499,996 ​ ​ 5,308 ​ ​ (6,786) ​ ​ — ​ ​ 498,518 Residential mortgage-backed securities ​ 1,786,062 ​ 18,587 ​ (18,329) ​ ​ — ​ 1,786,320 Corporate debt securities ​ 134,783 ​ 964 ​ (1,427) ​ ​ — ​ 134,320 Debt securities available for sale ​ $ 2,789,408 ​ $ 35,676 ​ $ (28,129) ​ $ — ​ $ 2,796,955 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ Fair December 31, 2020: Cost Gains Losses ​ ACL Value U.S. Treasury securities ​ $ 27,481 ​ $ 356 ​ $ — ​ $ — ​ $ 27,837 Obligations of U.S. government corporations and agencies ​ 67,406 ​ 2,162 ​ (49) ​ ​ — ​ 69,519 Obligations of states and political subdivisions ​ 292,940 ​ 11,779 ​ (8) ​ ​ — ​ 304,711 Commercial mortgage-backed securities ​ ​ 408,716 ​ ​ 10,212 ​ ​ (312) ​ ​ — ​ ​ 418,616 Residential mortgage-backed securities ​ 1,344,047 ​ 24,571 ​ (303) ​ ​ — ​ 1,368,315 Corporate debt securities ​ 70,953 ​ 1,237 ​ (1) ​ ​ — ​ 72,189 Debt securities available for sale ​ $ 2,211,543 ​ $ 50,317 ​ $ (673) ​ ​ — ​ $ 2,261,187 ​ Amortized cost and fair value of debt securities by contractual maturity or pre-refunded date are shown below. Mortgages underlying mortgage-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, 2021 ​ Amortized Fair ​ Cost Value Due in one year or less ​ $ 100,016 ​ $ 100,789 Due after one year through five years ​ 291,357 ​ 297,624 Due after five years through ten years ​ 303,453 ​ 309,672 Due after ten years ​ 2,094,582 ​ 2,088,870 Debt securities available for sale ​ $ 2,789,408 ​ $ 2,796,955 ​ 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, ​ 2021 2020 Gross security gains ​ $ 25 ​ $ 1,561 Gross security (losses) ​ ​ — ​ ​ (5) Net gains (losses) on sales of debt securities (1) ​ $ 25 ​ $ 1,556 (1) Net gains (losses) on sales of securities reported on the unaudited Consolidated Statements of Income includes sales of equity securities, excluded in this table. ​ Debt securities with carrying amounts of $562.6 million on March 31, 2021, and $628.0 million on December 31, 2020, were pledged as collateral for public deposits, securities sold under agreements to repurchase, and for other purposes as required. ​ The following information pertains to debt securities with gross unrealized losses, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ Fair Unrealized Fair Unrealized Fair Unrealized March 31, 2021: Value Losses Value Losses Value Losses Debt securities available for sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of U.S. government corporations and agencies ​ $ — ​ $ — ​ $ 4,695 ​ $ (45) ​ $ 4,695 ​ $ (45) Obligations of states and political subdivisions ​ ​ 58,555 ​ ​ (1,542) ​ ​ — ​ ​ — ​ ​ 58,555 ​ ​ (1,542) Commercial mortgage-backed securities ​ ​ 314,109 ​ ​ (6,786) ​ ​ — ​ ​ — ​ ​ 314,109 ​ ​ (6,786) Residential mortgage-backed securities ​ 1,019,462 ​ (18,325) ​ 352 ​ (4) ​ 1,019,814 ​ (18,329) Corporate debt securities ​ 95,164 ​ (1,427) ​ — ​ — ​ 95,164 ​ (1,427) Total temporarily impaired securities ​ $ 1,487,290 ​ $ (28,080) ​ $ 5,047 ​ $ (49) ​ $ 1,492,337 ​ $ (28,129) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ Fair Unrealized Fair Unrealized Fair Unrealized December 31, 2020: Value Losses Value Losses Value Losses Debt securities available for sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of U.S. government corporations and agencies ​ $ — ​ $ — ​ $ 4,957 ​ $ (49) ​ $ 4,957 ​ $ (49) Obligations of states and political subdivisions ​ ​ 762 ​ ​ (8) ​ ​ — ​ ​ — ​ ​ 762 ​ ​ (8) Commercial mortgage-backed securities ​ ​ 129,655 ​ ​ (312) ​ ​ — ​ ​ — ​ ​ 129,655 ​ ​ (312) Residential mortgage-backed securities ​ 89,997 ​ (300) ​ 139 ​ (3) ​ 90,136 ​ (303) Corporate debt securities ​ 1,499 ​ (1) ​ — ​ — ​ 1,499 ​ (1) Total temporarily impaired securities ​ $ 221,913 ​ $ (621) ​ $ 5,096 ​ $ (52) ​ $ 227,009 ​ $ (673) ​ Debt securities available for sale are not within the scope of CECL, however, the accounting for credit losses on these securities is affected by ASC 326-30. As of March 31, 2021, the Company’s debt security portfolio consisted of 31, 2020. The total number of debt securities in the investment portfolio in an unrealized loss position as of March 31, 2021, was of the aggregate fair value. The total number of debt securities in the investment portfolio in an unrealized loss position as of December 31, 2020, was of the aggregate fair value. Unrealized losses related to changes in market interest rates and market conditions that do not represent credit-related impairments. Furthermore, the Company does not intend to sell such securities 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, the impairment related to noncredit factors is recognized in accumulated other comprehensive income (loss), net of applicable taxes. As of March 31, 2021, the Company did not hold general obligation bonds of any single issuer, the aggregate of which exceeded 10% of the Company’s stockholders’ equity.

Portfolio Loans

Portfolio Loans	3 Months Ended
	Mar. 31, 2021
Portfolio Loans
Portfolio loans	Note 4: Portfolio Loans ​ Distributions of portfolio loans are as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Commercial ​ $ 2,067,371 ​ $ 2,014,576 Commercial real estate ​ ​ 2,912,966 ​ ​ 2,892,535 Real estate construction ​ ​ 422,633 ​ ​ 461,786 Retail real estate ​ ​ 1,343,299 ​ ​ 1,407,852 Retail other ​ ​ 33,031 ​ ​ 37,428 Portfolio loans ​ $ 6,779,300 ​ $ 6,814,177 ​ ​ ​ ​ ​ ​ ​ ACL ​ ​ (93,943) ​ ​ (101,048) Portfolio loans, net ​ $ 6,685,357 ​ $ 6,713,129 ​ Net deferred loan origination fees included in the balances above were ($3.4) million as of March 31, 2021, compared to $2.4 million of net deferred loan origination costs as of December 31, 2020. Net accretable purchase accounting adjustments included in the balances above reduced loans by 31, 2020. The March 31, 2021, commercial balance includes loans originated under PPP with an amortized cost of ​ The Company 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 the Company’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 the Company 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. Most commercial lending relationships that are million or less are processed through an expedited underwriting process. Most commercial loans greater than million are included in a portfolio review at least annually. Commercial loans greater than million that have a grading of special mention or worse are 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 of portfolio loans (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ ​ ​ Special ​ Substandard ​ Pass Watch Mention Substandard Non-accrual Commercial ​ $ 1,830,063 ​ $ 123,390 ​ $ 78,546 ​ $ 27,423 ​ $ 7,949 Commercial real estate ​ 2,400,446 ​ 407,244 ​ 68,900 ​ 31,212 ​ 5,164 Real estate construction ​ 400,306 ​ 19,918 ​ 9 ​ 2,400 ​ — Retail real estate ​ 1,318,247 ​ 9,879 ​ 2,376 ​ 4,302 ​ 8,495 Retail other ​ 32,933 ​ — ​ — ​ — ​ 98 Portfolio loans ​ $ 5,981,995 ​ $ 560,431 ​ $ 149,831 ​ $ 65,337 ​ $ 21,706 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Special ​ Substandard ​ Pass Watch Mention Substandard Non-accrual Commercial ​ $ 1,768,755 ​ $ 136,948 ​ $ 72,447 ​ $ 27,903 ​ $ 8,523 Commercial real estate ​ 2,393,372 ​ 383,277 ​ 75,486 ​ 34,897 ​ 5,503 Real estate construction ​ 434,681 ​ 24,481 ​ 77 ​ 2,546 ​ 1 Retail real estate ​ 1,382,616 ​ 10,264 ​ 2,471 ​ 3,702 ​ 8,799 Retail other ​ 37,324 ​ — ​ — ​ — ​ 104 Portfolio loans ​ $ 6,016,748 ​ $ 554,970 ​ $ 150,481 ​ $ 69,048 ​ $ 22,930 ​ Risk grades of portfolio loans, further sorted by origination year, are as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Risk Grade Ratings Term Loans Amortized Cost Basis by Origination Year ​ ​ Revolving ​ ​ ​ As of March 31, 2021 2021 2020 2019 2018 2017 ​ ​ Prior ​ ​ loans ​ ​ Total Commercial: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 388,147 ​ $ 536,074 ​ $ 131,127 ​ $ 97,322 ​ $ 88,238 ​ $ 126,916 ​ $ 462,239 ​ $ 1,830,063 Watch ​ ​ 4,830 ​ ​ 14,828 ​ ​ 18,085 ​ ​ 6,890 ​ ​ 9,185 ​ ​ 12,947 ​ ​ 56,625 ​ ​ 123,390 Special Mention ​ ​ 2,061 ​ ​ 4,241 ​ ​ 5,590 ​ ​ 8,369 ​ ​ 6,680 ​ ​ 18,831 ​ ​ 32,774 ​ ​ 78,546 Substandard ​ ​ 587 ​ ​ 8,912 ​ ​ 3,569 ​ ​ 2,993 ​ ​ 1,815 ​ ​ 125 ​ ​ 9,422 ​ ​ 27,423 Substandard non-accrual ​ ​ — ​ ​ 501 ​ ​ 2,392 ​ ​ 336 ​ ​ 2,168 ​ ​ 552 ​ ​ 2,000 ​ ​ 7,949 Total commercial ​ ​ 395,625 ​ ​ 564,556 ​ ​ 160,763 ​ ​ 115,910 ​ ​ 108,086 ​ ​ 159,371 ​ ​ 563,060 ​ ​ 2,067,371 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 195,095 ​ ​ 732,186 ​ ​ 462,732 ​ ​ 342,786 ​ ​ 315,383 ​ ​ 334,934 ​ ​ 17,330 ​ ​ 2,400,446 Watch ​ ​ 13,209 ​ ​ 91,440 ​ ​ 133,721 ​ ​ 89,517 ​ ​ 29,142 ​ ​ 48,557 ​ ​ 1,658 ​ ​ 407,244 Special Mention ​ ​ 19,920 ​ ​ 9,818 ​ ​ 7,902 ​ ​ 9,949 ​ ​ 7,172 ​ ​ 13,716 ​ ​ 423 ​ ​ 68,900 Substandard ​ ​ 2,500 ​ ​ 15,325 ​ ​ 3,557 ​ ​ 2,425 ​ ​ 4,400 ​ ​ 3,005 ​ ​ — ​ ​ 31,212 Substandard non-accrual ​ ​ — ​ ​ 784 ​ ​ 739 ​ ​ 821 ​ ​ 882 ​ ​ 1,938 ​ ​ — ​ ​ 5,164 Total commercial real estate ​ ​ 230,724 ​ ​ 849,553 ​ ​ 608,651 ​ ​ 445,498 ​ ​ 356,979 ​ ​ 402,150 ​ ​ 19,411 ​ ​ 2,912,966 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate construction: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 40,766 ​ ​ 167,230 ​ ​ 143,555 ​ ​ 39,297 ​ ​ 1,164 ​ ​ 1,680 ​ ​ 6,614 ​ ​ 400,306 Watch ​ ​ 2,079 ​ ​ 11,915 ​ ​ 3,653 ​ ​ 330 ​ ​ 1,785 ​ ​ 156 ​ ​ — ​ ​ 19,918 Special Mention ​ ​ — ​ ​ — ​ ​ 9 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 9 Substandard ​ ​ — ​ ​ 2,400 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,400 Substandard non-accrual ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Total real estate construction ​ ​ 42,845 ​ ​ 181,545 ​ ​ 147,217 ​ ​ 39,627 ​ ​ 2,949 ​ ​ 1,836 ​ ​ 6,614 ​ ​ 422,633 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 161,016 ​ ​ 207,536 ​ ​ 144,201 ​ ​ 118,052 ​ ​ 117,359 ​ ​ 351,700 ​ ​ 218,383 ​ ​ 1,318,247 Watch ​ ​ 189 ​ ​ 2,557 ​ ​ 2,040 ​ ​ 1,407 ​ ​ 291 ​ ​ 846 ​ ​ 2,549 ​ ​ 9,879 Special Mention ​ ​ 377 ​ ​ 33 ​ ​ — ​ ​ 18 ​ ​ — ​ ​ 1,948 ​ ​ — ​ ​ 2,376 Substandard ​ ​ 323 ​ ​ 882 ​ ​ 91 ​ ​ 56 ​ ​ 168 ​ ​ 2,497 ​ ​ 285 ​ ​ 4,302 Substandard non-accrual ​ ​ 483 ​ ​ 137 ​ ​ 76 ​ ​ 650 ​ ​ 1,128 ​ ​ 4,818 ​ ​ 1,203 ​ ​ 8,495 Total retail real estate ​ ​ 162,388 ​ ​ 211,145 ​ ​ 146,408 ​ ​ 120,183 ​ ​ 118,946 ​ ​ 361,809 ​ ​ 222,420 ​ ​ 1,343,299 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail other: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 2,014 ​ ​ 6,835 ​ ​ 8,062 ​ ​ 4,652 ​ ​ 1,949 ​ ​ 800 ​ ​ 8,621 ​ ​ 32,933 Watch ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Special Mention ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard non-accrual ​ ​ — ​ ​ 14 ​ ​ 7 ​ ​ 5 ​ ​ 14 ​ ​ 58 ​ ​ — ​ ​ 98 Total retail other ​ ​ 2,014 ​ ​ 6,849 ​ ​ 8,069 ​ ​ 4,657 ​ ​ 1,963 ​ ​ 858 ​ ​ 8,621 ​ ​ 33,031 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total portfolio loans ​ $ 833,596 ​ $ 1,813,648 ​ $ 1,071,108 ​ $ 725,875 ​ $ 588,923 ​ $ 926,024 ​ $ 820,126 ​ $ 6,779,300 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Risk Grade Ratings Term Loans Amortized Cost Basis by Origination Year ​ ​ Revolving ​ ​ ​ As of December 31, 2020 2020 2019 2018 2017 2016 ​ ​ Prior ​ ​ loans ​ ​ Total Commercial: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 812,536 ​ $ 158,307 ​ $ 107,565 ​ $ 93,190 ​ $ 61,847 ​ $ 79,970 ​ $ 455,340 ​ $ 1,768,755 Watch ​ ​ 16,544 ​ ​ 22,247 ​ ​ 14,954 ​ ​ 13,724 ​ ​ 2,577 ​ ​ 10,943 ​ ​ 55,959 ​ ​ 136,948 Special Mention ​ ​ 6,402 ​ ​ 2,671 ​ ​ 2,069 ​ ​ 7,164 ​ ​ 6,763 ​ ​ 13,733 ​ ​ 33,645 ​ ​ 72,447 Substandard ​ ​ 7,772 ​ ​ 3,791 ​ ​ 2,371 ​ ​ 1,939 ​ ​ 819 ​ ​ 1,233 ​ ​ 9,978 ​ ​ 27,903 Substandard non-accrual ​ ​ 150 ​ ​ 3,045 ​ ​ 451 ​ ​ 2,168 ​ ​ 641 ​ ​ 68 ​ ​ 2,000 ​ ​ 8,523 Total commercial ​ ​ 843,404 ​ ​ 190,061 ​ ​ 127,410 ​ ​ 118,185 ​ ​ 72,647 ​ ​ 105,947 ​ ​ 556,922 ​ ​ 2,014,576 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 717,559 ​ ​ 503,977 ​ ​ 360,573 ​ ​ 384,843 ​ ​ 180,555 ​ ​ 227,068 ​ ​ 18,797 ​ ​ 2,393,372 Watch ​ ​ 88,297 ​ ​ 110,526 ​ ​ 90,412 ​ ​ 33,734 ​ ​ 32,887 ​ ​ 27,023 ​ ​ 398 ​ ​ 383,277 Special Mention ​ ​ 16,490 ​ ​ 8,858 ​ ​ 10,490 ​ ​ 10,505 ​ ​ 7,102 ​ ​ 21,808 ​ ​ 233 ​ ​ 75,486 Substandard ​ ​ 17,445 ​ ​ 4,166 ​ ​ 1,491 ​ ​ 7,812 ​ ​ 2,111 ​ ​ 1,377 ​ ​ 495 ​ ​ 34,897 Substandard non-accrual ​ ​ 1,091 ​ ​ 776 ​ ​ 821 ​ ​ 882 ​ ​ 286 ​ ​ 1,647 ​ ​ — ​ ​ 5,503 Total commercial real estate ​ ​ 840,882 ​ ​ 628,303 ​ ​ 463,787 ​ ​ 437,776 ​ ​ 222,941 ​ ​ 278,923 ​ ​ 19,923 ​ ​ 2,892,535 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate construction: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 179,232 ​ ​ 171,663 ​ ​ 64,025 ​ ​ 1,468 ​ ​ 761 ​ ​ 1,444 ​ ​ 16,088 ​ ​ 434,681 Watch ​ ​ 18,485 ​ ​ 3,657 ​ ​ 337 ​ ​ 1,838 ​ ​ 164 ​ ​ ​ ​ ​ ​ ​ ​ 24,481 Special Mention ​ ​ 67 ​ ​ 10 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 77 Substandard ​ ​ 2,400 ​ ​ — ​ ​ — ​ ​ — ​ ​ 146 ​ ​ — ​ ​ — ​ ​ 2,546 Substandard non-accrual ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 1 ​ ​ — ​ ​ 1 Total real estate construction ​ ​ 200,184 ​ ​ 175,330 ​ ​ 64,362 ​ ​ 3,306 ​ ​ 1,071 ​ ​ 1,445 ​ ​ 16,088 ​ ​ 461,786 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 319,302 ​ ​ 162,711 ​ ​ 135,065 ​ ​ 136,427 ​ ​ 140,600 ​ ​ 257,147 ​ ​ 231,364 ​ ​ 1,382,616 Watch ​ ​ 2,715 ​ ​ 2,053 ​ ​ 1,396 ​ ​ 349 ​ ​ 579 ​ ​ 233 ​ ​ 2,939 ​ ​ 10,264 Special Mention ​ ​ 509 ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,962 ​ ​ — ​ ​ — ​ ​ 2,471 Substandard ​ ​ 899 ​ ​ 96 ​ ​ 56 ​ ​ 26 ​ ​ 727 ​ ​ 1,631 ​ ​ 267 ​ ​ 3,702 Substandard non-accrual ​ ​ 687 ​ ​ 78 ​ ​ 646 ​ ​ 1,147 ​ ​ 233 ​ ​ 4,815 ​ ​ 1,193 ​ ​ 8,799 Total retail real estate ​ ​ 324,112 ​ ​ 164,938 ​ ​ 137,163 ​ ​ 137,949 ​ ​ 144,101 ​ ​ 263,826 ​ ​ 235,763 ​ ​ 1,407,852 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail other: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 8,357 ​ ​ 9,430 ​ ​ 5,600 ​ ​ 2,516 ​ ​ 691 ​ ​ 440 ​ ​ 10,290 ​ ​ 37,324 Watch ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Special Mention ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard non-accrual ​ ​ 14 ​ ​ 7 ​ ​ 5 ​ ​ 15 ​ ​ 5 ​ ​ 57 ​ ​ 1 ​ ​ 104 Total retail other ​ ​ 8,371 ​ ​ 9,437 ​ ​ 5,605 ​ ​ 2,531 ​ ​ 696 ​ ​ 497 ​ ​ 10,291 ​ ​ 37,428 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total portfolio loans ​ $ 2,216,953 ​ $ 1,168,069 ​ $ 798,327 ​ $ 699,747 ​ $ 441,456 ​ $ 650,638 ​ $ 838,987 ​ $ 6,814,177 ​ 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) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ ​ Loans past due, still accruing ​ Non-accrual ​ 30-59 Days 60-89 Days 90+Days Loans Commercial ​ $ 52 ​ $ 2,614 ​ $ — ​ $ 7,949 Commercial real estate ​ ​ 4,377 ​ ​ — ​ ​ — ​ ​ 5,164 Real estate construction ​ — ​ — ​ — ​ — Retail real estate ​ ​ 2,248 ​ ​ 621 ​ ​ 1,149 ​ ​ 8,495 Retail other ​ 8 ​ 9 ​ — ​ 98 Past due and non-accrual loans ​ $ 6,685 ​ $ 3,244 ​ $ 1,149 ​ $ 21,706 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Loans past due, still accruing ​ Non-accrual ​ 30-59 Days 60-89 Days 90+Days Loans Commercial ​ $ 243 ​ $ — ​ $ — ​ $ 8,523 Commercial real estate ​ — ​ ​ — ​ ​ — ​ ​ 5,503 Real estate construction ​ 237 ​ 235 ​ — ​ 1 Retail real estate ​ 6,248 ​ ​ 400 ​ ​ 1,305 ​ ​ 8,799 Retail other ​ 66 ​ 149 ​ 66 ​ 104 Past due and non-accrual loans ​ $ 6,794 ​ $ 784 ​ $ 1,371 ​ $ 22,930 ​ Gross interest income recorded on 90+ day 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 $0.5 million for the three months ended March 31, 2021 and 2020. The amount of interest collected on those loans and recognized on a cash basis that was included in interest income was insignificant for the three months ended March 31, 2021 and 2020. ​ A summary of TDR loans is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 In compliance with modified terms ​ ​ 3,135 ​ ​ 3,814 30 – ​ ​ 164 ​ ​ 15 Included in non-performing loans ​ ​ 1,338 ​ ​ 1,249 TDR loans ​ $ 4,637 ​ $ 5,078 ​ We did not newly classify any loans as TDRs during the three months ended March 31, 2021, that were in compliance with their modified terms or 30 – 89 days past due. During the three months ended March 31, 2021, one commercial loan for $0.5 million was newly classified as a non-performing TDR. This loan had been non-accrual since the second quarter of 2020. Also, during the three months ended March 31, 2021, one retail real estate loan for $0.1 million that had been a performing TDR for longer than 12 months became non-performing. During the three months ended March 31, 2020, three commercial loans for $0.5 million and one commercial real estate loan for $0.7 million were newly classified as non-performing TDRs. These loans had been non-accrual since 2019. ​ There were no TDRs that were entered into during the last 12 months that were subsequently classified as non-performing and had payment defaults (a default occurs when a loan is 90 days or more past due or transferred to non-accrual) during the three months ended March 31, 2021 or 2020. ​ Gross interest income that would have been recorded in the three months ended March 31, 2021 and 2020, if TDRs had performed in accordance with their original terms compared with their modified terms, was insignificant. ​ Modified loans with payment deferrals that fall under the CARES Act or revised Interagency Statement that suspended requirements under GAAP related to TDR classification are not included in the Company’s TDR totals. ​ At March 31, 2021, the Company had $0.4 million of residential real estate in the process of foreclosure. The Company follows FHFA guidelines on single-family foreclosures and real estate owned evictions on portfolio loans. The agency has extended the moratoriums on single-family foreclosures and real estate owned evictions until at least June 30, 2021. Additionally, the Company follows all COVID-19 related state foreclosure and eviction orders. As these guidelines and orders may likely be updated, most foreclosures will be delayed into late-2021 or beyond. ​ The following tables provide details of loans evaluated individually, segregated by category. The Company evaluates loans with disparate risk characteristics on an individual basis. The unpaid contractual principal balance represents the customer outstanding balance excluding any partial charge-offs. Amortized cost represents customer balances net of any partial charge-offs recognized on the loan. Average amortized cost is calculated using the most recent four quarters (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ Unpaid Amortized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ Cost ​ Amortized ​ Total ​ ​ ​ ​ Average ​ ​ Principal ​ with No ​ Cost ​ Amortized ​ Related ​ Amortized ​ Balance Allowance with Allowance Cost Allowance Cost Commercial ​ $ 16,008 ​ $ 2,987 ​ $ 4,817 ​ $ 7,804 ​ $ 2,483 ​ $ 7,524 Commercial real estate ​ 6,523 ​ ​ 5,552 ​ ​ — ​ 5,552 ​ — ​ 8,075 Real estate construction ​ 287 ​ 287 ​ — ​ 287 ​ — ​ 450 Retail real estate ​ 5,342 ​ 4,959 ​ 25 ​ 4,984 ​ 25 ​ 5,560 Retail other ​ — ​ — ​ — ​ — ​ — ​ — Loans evaluated individually ​ $ 28,160 ​ $ 13,785 ​ $ 4,842 ​ $ 18,627 ​ $ 2,508 ​ $ 21,609 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Unpaid Amortized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ Cost ​ Amortized ​ Total ​ ​ ​ ​ Average ​ ​ Principal ​ with No ​ Cost ​ Amortized ​ Related ​ Amortized ​ Balance Allowance with Allowance Cost Allowance Cost Commercial ​ $ 16,771 ​ $ 4,001 ​ $ 4,371 ​ $ 8,372 ​ $ 1,600 ​ $ 7,920 Commercial real estate ​ 7,406 ​ ​ 6,067 ​ ​ — ​ 6,067 ​ — ​ 9,349 Real estate construction ​ 292 ​ 292 ​ — ​ 292 ​ — ​ 581 Retail real estate ​ 5,873 ​ 5,490 ​ 25 ​ 5,515 ​ 25 ​ 7,439 Retail other ​ — ​ — ​ — ​ — ​ — ​ 10 Loans evaluated individually ​ $ 30,342 ​ $ 15,850 ​ $ 4,396 ​ $ 20,246 ​ $ 1,625 ​ $ 25,299 ​ 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 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 underlying collateral, less estimated costs to sell. As of March 31, 2021, there were ​ 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 the Company’s historical loss experience beginning in 2010. As of March 31, 2021, the Company expects the markets in which it operates to experience continued economic uncertainty around the levels of delinquencies over the next 12 months. Management adjusted the historical loss experience for these expectations with an immediate reversion to historical loss rate beyond this forecast period. PPP loans were excluded from the ACL calculation as they are 100% government guaranteed. ​ The following table details activity in the ACL. Allocation of a portion of the ACL to one category does not preclude its availability to absorb losses in other categories (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of and for the Three Months Ended March 31, 2021 ​ ​ ​ ​ Commercial Real Estate Retail ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Real Estate Retail Other Total ACL beginning balance ​ $ 23,866 ​ $ 46,230 ​ $ 8,193 ​ $ 21,992 ​ $ 767 ​ $ 101,048 Provision for credit losses ​ (665) ​ (2,695) ​ (1,250) ​ (2,276) ​ 90 ​ (6,796) Charged-off ​ (262) ​ (303) ​ (209) ​ ​ (3) ​ (187) ​ (964) Recoveries ​ 86 ​ 74 ​ 145 ​ 265 ​ 85 ​ 655 ACL ending balance ​ $ 23,025 ​ $ 43,306 ​ $ 6,879 ​ $ 19,978 ​ $ 755 ​ $ 93,943 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of and for the Three Months Ended March 31, 2020 ​ ​ ​ ​ Commercial Real Estate Retail Real ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Estate Retail Other Total Beginning balance, prior to adoption of ASC ​ $ 18,291 ​ $ 21,190 ​ $ 3,204 ​ $ 10,495 ​ $ 568 ​ $ 53,748 Adoption of ASC ​ ​ 715 ​ ​ 9,306 ​ ​ 2,954 ​ ​ 3,292 ​ ​ 566 ​ ​ 16,833 Provision for credit losses ​ 5,673 ​ 6,526 ​ 889 ​ 4,037 ​ 91 ​ 17,216 Charged-off ​ (2,042) ​ (1,099) ​ — ​ ​ (708) ​ (299) ​ (4,148) Recoveries ​ 88 ​ 44 ​ 146 ​ 338 ​ 119 ​ 735 ACL ending balance ​ $ 22,725 ​ $ 35,967 ​ $ 7,193 ​ $ 17,454 ​ $ 1,045 ​ $ 84,384 ​ The following table presents the ACL and amortized cost of portfolio loans by category (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of March 31, 2021 ​ ​ ​ ​ Commercial Real Estate Retail Real ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Estate Retail Other Total ACL: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance attributed to: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 2,483 ​ $ — ​ $ — ​ $ 25 ​ $ — ​ $ 2,508 Loans collectively evaluated for impairment ​ 20,542 ​ 43,306 ​ 6,879 ​ 19,953 ​ 755 ​ 91,435 ACL ending balance ​ $ 23,025 ​ $ 43,306 ​ $ 6,879 ​ $ 19,978 ​ $ 755 ​ $ 93,943 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 7,804 ​ $ 3,644 ​ $ 287 ​ $ 4,613 ​ $ — ​ $ 16,348 Loans collectively evaluated for impairment ​ 2,059,567 ​ 2,907,414 ​ ​ 422,346 ​ 1,338,315 ​ 33,031 ​ 6,760,673 PCD loans evaluated for impairment ​ ​ — ​ ​ 1,908 ​ ​ — ​ ​ 371 ​ ​ — ​ ​ 2,279 Loans ending balance ​ $ 2,067,371 ​ $ 2,912,966 ​ $ 422,633 ​ $ 1,343,299 ​ $ 33,031 ​ $ 6,779,300 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ ​ ​ Commercial Real Estate Retail Real ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Estate Retail Other Total ACL: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance attributed to: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 1,600 ​ $ — ​ $ — ​ $ 25 ​ $ — ​ $ 1,625 Loans collectively evaluated for impairment ​ 22,266 ​ 46,230 ​ 8,193 ​ 21,967 ​ 767 ​ 99,423 ACL ending balance ​ $ 23,866 ​ $ 46,230 ​ $ 8,193 ​ $ 21,992 ​ $ 767 ​ $ 101,048 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 8,372 ​ $ 4,161 ​ $ 292 ​ $ 5,149 ​ $ — ​ $ 17,974 Loans collectively evaluated for impairment ​ 2,006,204 ​ 2,886,468 ​ ​ 461,494 ​ 1,402,337 ​ 37,428 ​ 6,793,931 PCD loans evaluated for impairment ​ ​ — ​ ​ 1,906 ​ ​ — ​ ​ 366 ​ ​ — ​ ​ 2,272 Loans ending balance ​ $ 2,014,576 ​ $ 2,892,535 ​ $ 461,786 ​ $ 1,407,852 ​ $ 37,428 ​ $ 6,814,177 ​

Deposits

Deposits	3 Months Ended
	Mar. 31, 2021
Deposits
Deposits	Note 5: Deposits ​ The composition of deposits is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Demand deposits, noninterest-bearing ​ $ 2,859,492 ​ $ 2,552,039 Interest-bearing transaction deposits ​ 2,312,008 ​ 2,263,093 Saving deposits and money market deposits ​ 2,679,879 ​ ​ 2,743,369 Time deposits ​ 1,022,468 ​ 1,119,348 Total deposits ​ $ 8,873,847 ​ $ 8,677,849 ​ Additional information about our deposits is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Brokered savings deposits and money market deposits ​ $ 2,699 ​ $ 2,251 Brokered time deposits ​ ​ 5,259 ​ ​ 5,257 Aggregate amount of time deposits with a minimum denomination of $100,000 ​ ​ 502,968 ​ ​ 568,735 Aggregate amount of time deposits with a minimum denomination that meets or exceeds the FDIC insurance limit of $250,000 ​ ​ 155,401 ​ ​ 192,563 ​ As of March 31, 2021, the scheduled maturities of time deposits are as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, Scheduled maturities of time deposits: ​ 2021 April 1, 2021 – March 31, 2022 $ 704,942 April 1, 2022 – March 31, 2023 ​ 175,252 April 1, 2023 – March 31, 2024 ​ 98,282 April 1, 2024 – March 31, 2025 ​ 29,736 April 1, 2025 – March 31, 2026 ​ 14,253 Thereafter ​ 3 Total time deposits ​ $ 1,022,468 ​

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2021
Borrowings
Borrowings	Note 6: Borrowings ​ 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 the Company’s safekeeping agent. The Company may be required to provide additional collateral based on fluctuations in the fair value of the underlying securities. (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2021 2020 Securities sold under agreements to repurchase ​ $ 210,132 ​ $ 175,614 ​ Weighted average rate for securities sold under agreements to repurchase ​ ​ 0.11 % ​ 0.13 % ​ Federal funds purchased are short-term borrowings that generally mature between one . The Company had ​ Short-term borrowings of $4.7 million at March 31, 2021, and December 31, 2020, was composed of FHLB advances which mature in less than one year from date of origination and the portion of long-term FHLB debt which is due within the next 12 months. ​ On January 29, 2019, the Company entered into an Amended and Restated Credit Agreement providing for the Company’s $20.0 million revolving credit facility with an annual interest rate of one-month LIBOR plus a spread of 1.75% . The revolving credit facility was set to mature on April 30, 2021. Subsequent to quarter end, on April 21, 2021, the maturity was extended by amendment for an additional , to April 30, 2022. The revolving credit facility incurs a non-usage fee based on the undrawn amount. The Company had ​ Long-term debt is summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Notes payable, FHLB, original maturity of 5 years, collateralized by FHLB deposits, residential and commercial real estate loans and FHLB stock ​ $ 4,584 ​ $ 4,757 ​ As of March 31, 2021, and December 31, 2020, funds borrowed from the FHLB, listed above, consisted of one variable-rate note maturing in May 2023, with an interest rate of 3.04%. ​ On May 25, 2017, the Company issued $40.0 million of 3.75% senior notes that mature on May 25, 2022. The senior notes are payable semi-annually on each May 25 and November 25, commencing on November 25, 2017. The senior notes are not subject to optional redemption by the Company. Additionally, on May 25, 2017, the Company issued 25, 2027. The subordinated notes, which qualify as Tier 2 capital for First Busey, bear interest at an annual rate of , as calculated on each applicable determination date. The subordinated notes are payable semi-annually on each May 25 and November 25, commencing on November 25, 2017, during the 25, 2022. The subordinated notes have an optional redemption in whole or in part on any interest payment date on or after May 25, 2022. The senior notes and subordinated notes are unsecured obligations of the Company. ​ On June 1, 2020, the Company 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 First Busey, bear interest at an annual rate of , as calculated on each applicable determination date. The subordinated notes are payable semi-annually on each June 1 and December 1 during the 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. ​ Unamortized debt issuance costs related to senior notes and subordinated notes are presented in the following table (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Unamortized debt issuance costs related to: ​ ​ ​ ​ ​ ​ Senior notes issued in 2017 ​ $ 157 ​ $ 191 Subordinated notes issued in 2017 ​ ​ 625 ​ ​ 651 Subordinated notes issued in 2020 ​ ​ 2,005 ​ ​ 2,123 Total unamortized debt issuance costs ​ $ 2,787 ​ $ 2,965 ​

Regulatory Capital

Regulatory Capital	3 Months Ended
	Mar. 31, 2021
Regulatory Capital
Regulatory Capital	Note 7: Regulatory Capital ​ The Company 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 the Company'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, 2021, and December 31, 2020, all capital ratios of the Company and Busey Bank exceeded the well capitalized levels under the applicable regulatory capital adequacy guidelines. Management believes that no events or changes have occurred subsequent to March 31, 2021, that would change this designation. ​ On March 27, 2020, the FDIC and other federal banking agencies published an interim final rule that provides those banking organizations adopting 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. On August 26, 2020, the CECL final rule was finalized and was substantially similar to the interim final rule. Under this final rule, because the Company has elected to use the deferral option, the regulatory capital impact of our transition adjustments recorded on January 1, 2020, from the adoption of CECL will be deferred for two years, until January 1, 2022. 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, will be added to the deferred transition amounts (“adjusted transition amounts”) and deferred for the two-year period. At the conclusion of the two-year period the adjusted transition amounts will 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. ​ The following tables summarize the applicable holding company and bank regulatory capital requirements (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Minimum ​ ​ ​ ​ ​ ​ ​ Minimum ​ To Be Well ​ ​ Actual ​ Capital Requirement ​ Capitalized ​ Amount Ratio Amount Ratio Amount Ratio As of March 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,265,926 17.39 % $ 582,526 8.00 % $ 728,157 10.00 % Busey Bank ​ $ 1,167,199 16.06 % $ 581,457 8.00 % $ 726,821 10.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,007,986 13.84 % $ 436,894 6.00 % $ 582,526 8.00 % Busey Bank ​ $ 1,094,260 15.06 % $ 436,093 6.00 % $ 581,457 8.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Equity Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 933,986 12.83 % $ 327,671 4.50 % $ 473,302 6.50 % Busey Bank ​ $ 1,094,260 15.06 % $ 327,070 4.50 % $ 472,434 6.50 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Average Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,007,986 9.85 % $ 409,360 4.00 % N/A N/A ​ Busey Bank ​ $ 1,094,260 10.71 % $ 408,522 4.00 % $ 510,652 5.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Minimum ​ ​ ​ ​ ​ ​ ​ ​ Minimum ​ To Be Well ​ ​ ​ Actual ​ Capital Requirement ​ Capitalized ​ ​ Amount Ratio Amount Ratio Amount Ratio As of December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,245,997 17.04 % $ 585,015 8.00 % $ 731,269 10.00 % Busey Bank ​ $ 1,131,875 15.50 % $ 584,082 8.00 % $ 730,103 10.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 983,033 13.44 % $ 438,761 6.00 % $ 585,015 8.00 % Busey Bank ​ $ 1,053,910 14.44 % $ 438,062 6.00 % $ 584,082 8.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Equity Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 909,033 12.43 % $ 329,071 4.50 % $ 475,325 6.50 % Busey Bank ​ $ 1,053,910 14.44 % $ 328,546 4.50 % $ 474,567 6.50 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Average Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 983,033 9.79 % $ 401,717 4.00 % N/A N/A ​ Busey Bank ​ $ 1,053,910 10.52 % $ 400,581 4.00 % $ 500,727 5.00 % ​ 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 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 (i) total capital to risk-weighted assets of at least 10.50%, (ii) Tier 1 Capital to risk-weighted assets of at least 8.50%, and (iii) Common Equity Tier 1 to risk-weighted assets of at least 7.00%.

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2021
Stock-based Compensation
Stock-based Compensation	Note 8: Stock-Based Compensation ​ Under the terms of the 2020 Equity Plan, the Company has granted restricted stock units, deferred stock units and performance-based restricted stock unit awards. The Company grants restricted stock units to members of management periodically throughout the year. Each restricted stock unit is equivalent to share of the Company’s common stock. These units have requisite service periods ranging from one , subject to accelerated vesting upon eligible retirement from the Company. Recipients earn quarterly dividend equivalents on their respective units which entitle the recipients to additional units. Therefore, dividends earned each quarter compound based upon the updated unit balances. ​ The Company grants deferred stock units, which are restricted stock units with a deferred settlement date, to its directors and advisory directors. Each deferred stock unit is equivalent to share of the Company’s common stock. Deferred stock units vest over a period following the grant date. These units generally are subject to the same terms as restricted stock units under the 2020 Equity Plan, except that, following vesting, settlement occurs within following the earlier of separation from the board or a change in control of the Company. After vesting and prior to delivery, these units will continue to earn dividend equivalents. ​ The Company also grants performance-based restricted stock unit awards to members of management periodically throughout the year. Each performance-based restricted stock unit is equivalent to share of the Company’s common stock. The number of units that ultimately vest will be determined based on the achievement of the market or other performance goals, subject to accelerated service-based vesting conditions upon eligible retirement from the Company. ​ The Company has outstanding stock options assumed from acquisitions. ​ Upon vesting/delivery, shares are expected (though not required) to be issued from treasury. ​ Stock Option Plan ​ A summary of the status of, and changes in, the Company's stock option awards for the three months ended March 31, 2021, follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ Average ​ Remaining ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Shares Price Life Outstanding at beginning of period ​ 39,085 $ 23.53 ​ ​ 5.88 Exercised ​ — ​ — ​ ​ ​ Forfeited ​ — ​ ​ — ​ ​ ​ Expired ​ (5,279) ​ 23.53 ​ ​ ​ Outstanding at end of period ​ 33,806 $ 23.53 ​ 5.63 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at end of period ​ 33,806 $ 23.53 ​ 5.63 ​ The Company did not record any stock option compensation expense for the three months ended March 31, 2021, or 2020. As of March 31, 2021, the Company did not have any unrecognized stock option expense. ​ Restricted Stock Unit, Deferred Stock Unit, and Performance-Based Restricted Stock Unit Awards ​ A summary of changes in the Company’s restricted stock unit and deferred stock unit awards for the three months ended March 31, 2021, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Director ​ Weighted- ​ ​ Restricted ​ Average ​ Deferred ​ Average ​ ​ Stock ​ Grant Date ​ Stock ​ Grant Date ​ Units Fair Value Units Fair Value Non-vested at beginning of period ​ 1,017,038 $ 23.87 ​ 34,263 $ 17.18 Granted ​ 212,426 ​ 24.54 ​ 33,288 ​ 24.54 Dividend equivalents earned ​ 11,310 ​ 20.67 ​ 1,172 ​ 20.67 Vested ​ — ​ — ​ (791) ​ 20.67 Forfeited ​ (13,422) ​ 26.98 ​ — ​ — Non-vested at end of period ​ 1,227,352 $ 23.93 ​ 67,932 $ 20.81 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at end of period ​ 1,227,352 $ 23.93 ​ 71,835 $ 24.30 ​ On March 24, 2021, under the terms of the 2020 Equity Incentive Plan, the Company granted 212,426 restricted stock units to members of management, including the Vice-Chairman of the Board. The grant date fair value of the award totaled . The terms of these awards included an accelerated vesting provision upon eligible retirement from the Company, after a one-year minimum requisite service period. Subsequent to the requisite service period, the awards will become vested. Further, the Company granted deferred stock units to directors and advisory directors. The grant date fair value of the award totaled . Subsequent to the requisite service period, the awards will become ​ During the first quarter of 2021, the Company also granted a target of 70,815 market-based performance stock units with a maximum award of 113,304 units. The actual number of units issued at the vesting date could range from of the initial grant, depending on attaining the market-based total shareholder return performance goal. The grant date fair value of the award is estimated to be million and will be recognized in compensation expense over the performance period ending December 31, 2023. The Company expects to finalize the grant date fair value of these awards in the second quarter of 2021. ​ Further, during the first quarter of 2021, the Company granted a target of 28,344 performance-based stock units with a maximum award of 39,682 units. The actual number of units issued at the vest date could range from of the initial grant, depending on attaining a performance goal based upon the compounded annual growth rate of the Remittance Processing segment. The grant date fair value of the award is ​ The Company recognized $1.4 million and $1.1 million of compensation expense related to non-vested restricted stock units, deferred stock units, and performance-based restricted stock awards for the three months ended March 31, 2021 and 2020, respectively. As of March 31, 2021, there was million of total unrecognized compensation cost related to these non-vested stock awards. This cost is expected to be recognized over a weighted average period of ​ As of March 31, 2021, 1,094,149 shares remain available for issuance pursuant to the 2020 Equity Plan. The First Busey Corporation Employee Stock Purchase Plan expired as of December 31, 2020. The Company has included a proposal for approval of a new 2021 Employee Stock Purchase Plan within its Definitive Proxy Statement filed April 8, 2021.

Outstanding Commitments and Con

Outstanding Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2021
Outstanding Commitments and Contingent Liabilities
Outstanding Commitments and Contingent Liabilities	Note 9: Outstanding Commitments and Contingent Liabilities ​ Legal Matters ​ The Company is a party to legal actions which arise in the normal course of its business activities. In the opinion of management, the ultimate resolution of these matters is not expected to have a material effect on the Company’s financial position or results of operations. ​ Credit Commitments and Contingencies ​ A summary of the contractual amount of the Company’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, ​ 2021 2020 Financial instruments whose contract amounts represent credit risk: ​ ​ ​ ​ ​ ​ Commitments to extend credit ​ $ 1,759,035 ​ $ 1,754,370 Standby letters of credit ​ 39,643 ​ 38,937 ​

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2021
Derivative Financial Instruments
Derivative Financial Instruments	Note 10: Derivative Financial Instruments ​ The Company utilizes interest rate swap agreements as part of its asset liability management strategy to help manage its interest rate risk position. Additionally, the Company 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 with customers and other third parties. See “ Note 11: Fair Value Measurements ​ Interest Rate Swaps Designated as Cash Flow Hedges ​ The Company 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 other comprehensive income (loss) and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. The change in fair value of components excluded from the assessment of effectiveness are recognized in current earnings. ​ Interest rate swaps with notional amounts totaling $70.0 million as of March 31, 2021, and December 31, 2020, were designated as cash flow hedges to hedge the risk of variability in cash flows (future interest payments) attributable to changes in the contractually specified 3 month LIBOR benchmark interest rate on the Company’s junior subordinated debt owed to unconsolidated trusts and were determined to be highly effective during the period. The gross aggregate fair value of the swaps of 31, 2020, respectively, with changes in fair value recorded net of tax in other comprehensive income (loss). The Company expects the hedges to remain highly effective during the remaining terms of the swaps. ​ A summary of the interest-rate swaps designated as cash flow hedges is presented below (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ March 31, ​ December 31, ​ ​ 2021 2020 Notional amount ​ $ 70,000 ​ $ 70,000 ​ Weighted average fixed pay rates ​ 1.80 % 1.80 % Weighted average variable 3-month LIBOR receive rates ​ ​ 0.18 % ​ 0.22 % Weighted average maturity, in years ​ ​ 2.61 yrs ​ 2.85 yrs Unrealized gains (losses), net of tax ​ $ (1,575) ​ $ (2,184) ​ ​ Interest expense recorded on these swap transactions was $0.3 million during the three months ended March 31, 2021. The Company expects million of the unrealized loss to be reclassified from OCI to interest expense during the next three months. This reclassified amount could differ from amounts actually recognized due to changes in interest rates, hedge de-designations, and the addition of other hedges subsequent to March 31, 2021. ​ The following table reflects the net gains (losses) recorded in accumulated other comprehensive income (loss) and the unaudited Consolidated Statements of Income relating to cash flow derivative instruments for the periods presented (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, Interest rate contracts 2021 2020 Gain (loss) recognized in OCI, net of tax ​ $ 410 ​ $ (2,237) (Gain) loss reclassified from OCI to interest expense, net of tax ​ ​ 199 ​ ​ (11) Net change in unrealized gains (losses) on cash flow hedges ​ $ 609 ​ $ (2,248) ​ The Company pledged $2.4 million and $3.2 million in cash to secure its obligation under these contracts at March 31, 2021, and December 31, 2020, respectively. ​ Interest Rate Lock Commitments ​ Interest rate lock commitments that meet the definition of derivative financial instruments under ASC Topic 815, Derivatives and Hedging ​ Forward Sales Commitments ​ The Company 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 best-efforts 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 unaudited consolidated financial statements. While such forward sales commitments generally served as an economic hedge to mortgage loans held for sale and interest rate lock commitments, the Company 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 unaudited Consolidated Balance Sheets are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ December 31, 2020 ​ ​ ​ ​ ​ Notional ​ Fair ​ Notional ​ Fair Derivatives with positive fair value Location Amount Value Amount Value Interest rate lock commitments ​ Other assets ​ $ 24,142 ​ $ 474 ​ $ 45,004 ​ $ 1,201 Forward sales commitments ​ Other assets ​ ​ 7,035 ​ ​ 59 ​ ​ 978 ​ ​ 32 Mortgage banking derivatives recorded in other assets ​ $ 31,177 ​ $ 533 ​ $ 45,982 ​ $ 1,233 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives with negative fair value ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate lock commitments ​ Other liabilities ​ $ 931 ​ $ 2 ​ $ 118 ​ $ 1 Forward sales commitments ​ Other liabilities ​ ​ 55,454 ​ ​ 879 ​ ​ 84,964 ​ ​ 2,662 Mortgage banking derivatives recorded in other liabilities ​ $ 56,385 ​ $ 881 ​ $ 85,082 ​ $ 2,663 ​ Net gains (losses) relating to these derivative instruments are summarized as follows for the periods presented (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ Location ​ 2021 ​ 2020 Interest rate lock commitments ​ Mortgage revenue ​ $ 472 ​ $ 4,849 Forward sales commitments ​ Mortgage revenue ​ (820) ​ ​ (7,047) Net gains (losses) ​ ​ ​ ​ $ (348) ​ $ (2,198) ​ The impact of the net gains or losses on derivative financial instruments related to interest rate lock commitments issued to residential loan customers for loans that will be held for sale and forward sales commitments to sell residential mortgage loans to loan investors are almost entirely offset by a corresponding change in the fair value of loans held for sale. ​ Interest Rate Swaps Not Designated as Hedges ​ The Company may offer derivative contracts to its customers in connection with their risk management needs. The Company manages the risk associated with these contracts by entering into an equal and offsetting derivative with a third-party dealer. These contracts support variable rate, commercial loan relationships totaling 31, 2020, respectively. These derivatives generally worked together as an economic interest rate hedge, but the Company 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 unaudited Consolidated Balance Sheets are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Asset ​ Derivative Liability ​ ​ Notional ​ Fair ​ Notional ​ Fair March 31, 2021 Amount Value Amount Value Interest rate swaps – pay floating, receive fixed ​ $ 308,178 ​ $ 18,881 ​ $ 93,069 ​ $ 3,209 Interest rate swaps – pay fixed, receive floating ​ ​ 93,069 ​ ​ 3,209 ​ ​ 308,178 ​ ​ 18,881 Derivatives not designated as hedging instruments ​ $ 401,247 ​ $ 22,090 ​ $ 401,247 ​ $ 22,090 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Asset ​ Derivative Liability ​ ​ Notional ​ Fair ​ Notional ​ Fair December 31, 2020 Amount Value Amount Value Interest rate swaps – pay floating, receive fixed ​ $ 394,954 ​ $ 32,685 ​ $ — ​ $ — Interest rate swaps – pay fixed, receive floating ​ ​ — ​ ​ — ​ ​ 394,954 ​ ​ 32,685 Derivatives not designated as hedging instruments ​ $ 394,954 ​ $ 32,685 ​ $ 394,954 ​ $ 32,685 ​ Changes in fair value of these derivative assets and liabilities are recorded in non-interest expense in the unaudited Consolidated Statements of Income and summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ Location 2021 2020 Interest rate swaps – pay floating, receive fixed ​ Non-interest expense ​ $ (10,595) ​ $ 23,478 Interest rate swaps – pay fixed, receive floating ​ Non-interest expense ​ ​ 10,595 ​ ​ (23,478) Net change in fair value of interest rate swaps ​ ​ ​ ​ $ — ​ $ — ​ The Company pledged $25.6 million and $36.0 million in cash to secure its obligation under these contracts at March 31, 2021, and December 31, 2020, respectively.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Measurements
Fair Value Measurements	Note 11: 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 those Company 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 the Company'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. ​ Debt Securities Available for Sale ​ Debt securities classified as available for sale are reported at fair value utilizing Level 2 measurements. The Company 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, focusing on observable market data such as benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing, to prepare evaluations. ​ The independent pricing service uses model processes, such as the Option Adjusted Spread model, to assess interest rate impact and develop prepayment scenarios. The 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 measurements. For mutual funds, unadjusted quoted prices in active markets for identical assets are utilized to determine fair value at the measurement date and have been classified as Level 1. For stock, quoted prices for identical or similar assets in markets that are not active are utilized and classified as Level 2. ​ Loans Held for Sale ​ Loans held for sale are reported at fair value utilizing Level 2 measurements. The fair value of the mortgage loans held for sale are measured using observable quoted market or contract prices or market price equivalents and are classified as Level 2. ​ Derivative Assets and Derivative Liabilities ​ Derivative assets and derivative liabilities are reported at fair value utilizing Level 2 measurements. The fair value of derivative assets and liabilities is determined based on prices that are obtained from a third-party which uses observable market inputs. Derivative assets and liabilities are classified as Level 2. ​ The following tables summarize financial assets and financial liabilities measured at fair value on a recurring basis as of March 31, 2021, and December 31, 2020, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total March 31, 2021 Inputs Inputs Inputs Fair Value Debt securities available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ — ​ $ 23,757 ​ $ — ​ $ 23,757 Obligations of U.S. government corporations and agencies ​ ​ — ​ ​ 66,578 ​ ​ — ​ ​ 66,578 Obligations of states and political subdivisions ​ ​ — ​ ​ 287,462 ​ ​ — ​ ​ 287,462 Commercial mortgage-backed securities ​ ​ — ​ ​ 498,518 ​ ​ — ​ ​ 498,518 Residential mortgage-backed securities ​ ​ — ​ ​ 1,786,320 ​ ​ — ​ ​ 1,786,320 Corporate debt securities ​ ​ — ​ ​ 134,320 ​ ​ — ​ ​ 134,320 Equity securities ​ ​ — ​ ​ 7,146 ​ ​ — ​ ​ 7,146 Loans held for sale ​ ​ — ​ ​ 38,272 ​ ​ — ​ ​ 38,272 Derivative assets ​ ​ — ​ ​ 22,623 ​ ​ — ​ ​ 22,623 Derivative liabilities ​ ​ — ​ ​ 25,173 ​ ​ — ​ ​ 25,173 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total December 31, 2020 Inputs Inputs Inputs Fair Value Debt securities available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ — ​ $ 27,837 ​ $ — ​ $ 27,837 Obligations of U.S. government corporations and agencies ​ ​ — ​ ​ 69,519 ​ ​ — ​ ​ 69,519 Obligations of states and political subdivisions ​ ​ — ​ ​ 304,711 ​ ​ — ​ ​ 304,711 Commercial mortgage-backed securities ​ ​ — ​ ​ 418,616 ​ ​ — ​ ​ 418,616 Residential mortgage-backed securities ​ ​ — ​ ​ 1,368,315 ​ ​ — ​ ​ 1,368,315 Corporate debt securities ​ ​ — ​ ​ 72,189 ​ ​ — ​ ​ 72,189 Equity securities ​ ​ — ​ ​ 5,530 ​ ​ — ​ ​ 5,530 Loans held for sale ​ ​ — ​ ​ 42,813 ​ ​ — ​ ​ 42,813 Derivative assets ​ ​ — ​ ​ 33,918 ​ ​ — ​ ​ 33,918 Derivative liabilities ​ ​ — ​ ​ 38,403 ​ ​ — ​ ​ 38,403 ​ 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 ​ The Company 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. ​ OREO ​ Non-financial assets measured at fair value include OREO (upon initial recognition or subsequent impairment). OREO properties are measured using a combination of observable inputs, including recent appraisals, and unobservable inputs. Due to the significance of unobservable inputs, all OREO fair values have been classified as Level 3. ​ Bank Property Held for Sale ​ Bank property held for sale represents certain banking center office buildings which the Company 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 as of March 31, 2021, and December 31, 2020, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total March 31, 2021 Inputs Inputs Inputs Fair Value Loans evaluated individually ​ $ — ​ $ — ​ $ 2,334 ​ $ 2,334 OREO ​ — ​ — ​ 51 ​ 51 Bank property held for sale ​ — ​ — ​ 9,101 ​ 9,101 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total December 31, 2020 Inputs Inputs Inputs Fair Value Loans evaluated individually ​ $ — ​ $ — ​ $ 2,771 ​ $ 2,771 OREO ​ — ​ — ​ 106 ​ 106 Bank property held for sale ​ ​ — ​ — ​ 10,676 ​ 10,676 ​ 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) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quantitative Information about Level 3 Fair Value Measurements ​ ​ Fair Value ​ Valuation ​ Unobservable ​ Range March 31, 2021 Estimate Techniques Input (Weighted Average) Loans evaluated individually ​ $ 2,334 ​ Appraisal of collateral ​ Appraisal adjustments ​ -42.8 % to -100.0 % (-51.8) % OREO ​ ​ 51 ​ Appraisal of collateral ​ Appraisal adjustments ​ -33.0 % to -100.0 % (-67.9) % Bank property held for sale ​ ​ 9,101 ​ Appraisal of collateral or real estate listing price ​ Appraisal adjustments ​ -6.2 % to -64.9 % (-41.3) % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans evaluated individually ​ $ 2,771 ​ Appraisal of collateral ​ Appraisal adjustments ​ -30.0 % to -100.0 % (-37.0) % OREO ​ ​ 106 ​ Appraisal of collateral ​ Appraisal adjustments ​ -25.0 % to -100.0 % (-54.5) % Bank property held for sale ​ ​ 10,676 ​ Appraisal of collateral or real estate listing price ​ Appraisal adjustments ​ -6.2 % to -64.9 % (-42.8) % ​ Estimated fair values of financial instruments that are reported at amortized cost in the Company’s unaudited Consolidated Balance Sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ December 31, 2020 ​ ​ Carrying Fair Carrying Fair ​ ​ Amount Value Amount Value Financial assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 404,802 ​ $ 404,802 ​ $ 688,537 ​ $ 688,537 Level 2 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued interest receivable ​ 31,876 ​ 31,876 ​ 33,240 ​ 33,240 Level 3 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Portfolio loans, net ​ 6,685,357 ​ 6,740,655 ​ 6,713,129 ​ 6,755,425 Mortgage servicing rights ​ ​ 10,409 ​ ​ 12,461 ​ ​ 10,912 ​ ​ 11,107 Other servicing rights ​ ​ 1,528 ​ ​ 2,055 ​ ​ 1,434 ​ ​ 1,966 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 2 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Time deposits ​ $ 1,022,468 ​ $ 1,031,778 ​ $ 1,119,348 ​ $ 1,132,107 Securities sold under agreements to repurchase ​ 210,132 ​ 210,132 ​ 175,614 ​ 175,614 Short-term borrowings ​ ​ 4,663 ​ ​ 4,669 ​ ​ 4,658 ​ ​ 4,661 Long-term debt ​ 4,584 ​ 4,806 ​ ​ 4,757 ​ 5,014 Junior subordinated debt owed to unconsolidated trusts ​ 71,509 ​ 56,511 ​ 71,468 ​ 59,943 Accrued interest payable ​ 5,671 ​ 5,671 ​ 3,401 ​ 3,401 Level 3 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Senior notes, net of unamortized issuance costs ​ ​ 39,843 ​ ​ 40,066 ​ ​ 39,809 ​ ​ 40,104 Subordinated notes, net of unamortized issuance costs ​ ​ 182,370 ​ ​ 184,819 ​ ​ 182,226 ​ ​ 187,697 ​

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share
Earnings Per Share	Note 12: 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 deferred stock units 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 the Company’s outstanding stock options and warrants were exercised and restricted stock units were vested. ​ Earnings per common share have been computed as follows (dollars in thousands, except per share amounts) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, ​ 2021 2020 Net income ​ $ 37,816 ​ $ 15,364 Shares: ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding ​ 54,471,860 ​ 54,661,787 Dilutive effect of outstanding options, warrants, and restricted stock units as determined by the application of the treasury stock method ​ 563,946 ​ 251,542 Weighted average common shares outstanding, as adjusted for diluted earnings per share calculation ​ 55,035,806 ​ 54,913,329 ​ ​ ​ ​ ​ ​ ​ Basic earnings per common share ​ $ 0.69 ​ $ 0.28 ​ ​ ​ ​ ​ ​ ​ Diluted earnings per common share ​ $ 0.69 ​ $ 0.28 ​ ​ ​ ​ ​ ​ ​ Common stock equivalents excluded from the earning per common share calculations because their effect would have been anti-dilutive ​ ​ 358,279 ​ ​ 244,242 ​

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss).
Accumulated Other Comprehensive Income (Loss).	Note 13: Accumulated Other Comprehensive Income (Loss) ​ The following table represents changes in accumulated other comprehensive income (loss) by component, net of tax, for the periods below (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2021 ​ 2020 ​ ​ ​ Before Tax ​ ​ Tax Effect ​ ​ Net of Tax ​ ​ Before Tax ​ ​ Tax Effect ​ ​ Net of Tax Unrealized gains (losses) on debt securities available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at beginning of period ​ $ 49,644 ​ $ (14,151) ​ $ 35,493 ​ $ 21,192 ​ $ (6,032) ​ $ 15,160 Unrealized holding gains (losses) on debt securities available for sale, net ​ ​ (42,072) ​ ​ 11,993 ​ ​ (30,079) ​ ​ 30,086 ​ ​ (8,589) ​ ​ 21,497 Amounts reclassified from accumulated other comprehensive income, net ​ ​ (25) ​ ​ 7 ​ ​ (18) ​ ​ (1,556) ​ ​ 448 ​ ​ (1,108) Balance at end of period ​ $ 7,547 ​ $ (2,151) ​ $ 5,396 ​ $ 49,722 ​ $ (14,173) ​ $ 35,549 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized gains (losses) on cash flow hedges: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at beginning of period ​ $ (3,055) ​ $ 871 ​ $ (2,184) ​ $ (280) ​ $ 80 ​ $ (200) Unrealized holding gains (losses) on cash flow hedges, net ​ ​ 574 ​ ​ (164) ​ ​ 410 ​ ​ (3,129) ​ ​ 892 ​ ​ (2,237) Amounts reclassified from accumulated other comprehensive income, net ​ ​ 278 ​ ​ (79) ​ ​ 199 ​ ​ (15) ​ ​ 4 ​ ​ (11) Balance at end of period ​ $ (2,203) ​ $ 628 ​ $ (1,575) ​ $ (3,424) ​ $ 976 ​ $ (2,448) Total accumulated other comprehensive income (loss) ​ $ 5,344 ​ $ (1,523) ​ $ 3,821 ​ $ 46,298 ​ $ (13,197) ​ $ 33,101 ​

Operating Segments and Related

Operating Segments and Related Information	3 Months Ended
	Mar. 31, 2021
Operating Segments and Related Information
Operating Segments and Related Information	Note 14: Operating Segments and Related Information ​ The Company has three reportable operating segments: Banking, Remittance Processing, and Wealth Management. 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 through its banking center in Indianapolis, Indiana. The Remittance Processing operating segment provides solutions for online bill payments, lockbox, and walk-in payments. The Wealth Management operating segment provides a full range of asset management, investment, and fiduciary services to individuals, businesses and foundations, tax preparation, philanthropic advisory services, farms, and brokerage services. ​ The Company’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 “other” category consists of the Parent Company, First Busey Risk Management, and the elimination of intercompany transactions. ​ The segment financial information provided below has been derived from information used by management to monitor and manage the financial performance of the Company. The accounting policies of the Note 1. Significant Accounting Policies ” to the Company’s 2020 Annual Report. The Company accounts for intersegment revenue and transfers at current market value. ​ Following is a summary of selected financial information for the Company’s operating segments (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Goodwill ​ Total Assets ​ ​ As of ​ As of ​ ​ March 31, ​ December 31, ​ March 31, ​ December 31, ​ 2021 2020 2021 2020 Banking ​ $ 288,436 ​ $ 288,436 ​ $ 10,674,402 ​ $ 10,462,673 Remittance Processing ​ 8,992 ​ 8,992 ​ 46,765 ​ 46,553 Wealth Management ​ 14,108 ​ 14,108 ​ 50,392 ​ 46,504 Other ​ — ​ — ​ (11,996) ​ (11,683) Totals ​ $ 311,536 ​ $ 311,536 ​ $ 10,759,563 ​ $ 10,544,047 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2021 2020 Net interest income: ​ ​ ​ ​ ​ ​ Banking ​ $ 68,455 ​ $ 71,573 Remittance Processing ​ ​ 20 ​ ​ 19 Wealth Management ​ — ​ — Other ​ (3,582) ​ (2,159) Total net interest income ​ $ 64,893 ​ $ 69,433 ​ ​ ​ ​ ​ ​ ​ Non-interest income: ​ ​ ​ ​ ​ ​ Banking ​ $ 12,884 ​ $ 13,168 Remittance Processing ​ 4,861 ​ 4,069 Wealth Management ​ 12,587 ​ 11,709 Other ​ 1,113 ​ (1,429) Total non-interest income ​ $ 31,445 ​ $ 27,517 ​ ​ ​ ​ ​ ​ ​ Non-interest expense: ​ ​ ​ ​ ​ ​ Banking ​ $ 42,091 ​ $ 48,515 Remittance Processing ​ ​ 4,290 ​ ​ 2,903 Wealth Management ​ ​ 6,565 ​ ​ 6,974 Other ​ ​ 1,553 ​ ​ 2,122 Total non-interest expense ​ $ 54,499 ​ $ 60,514 ​ ​ ​ ​ ​ ​ ​ Income before income taxes: ​ ​ ​ ​ ​ ​ Banking ​ $ 46,044 ​ $ 19,010 Remittance Processing ​ ​ 591 ​ ​ 1,185 Wealth Management ​ ​ 6,022 ​ ​ 4,735 Other ​ ​ (4,022) ​ ​ (5,710) Total income before income taxes ​ $ 48,635 ​ $ 19,220 ​ ​ ​ ​ ​ ​ ​ Net income: ​ ​ ​ ​ ​ ​ Banking ​ $ 35,528 ​ $ 14,924 Remittance Processing ​ 429 ​ 860 Wealth Management ​ 4,682 ​ 3,599 Other ​ (2,823) ​ (4,019) Total net income ​ $ 37,816 ​ $ 15,364 ​

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases
Leases	Note 15: Leases ​ The Company has operating leases consisting primarily of equipment leases and real estate leases. The Company leases real estate property for banking centers, ATM locations, and office space with terms extending through 2032. As of March 31, 2021, the Company reported ​ The following tables represents lease costs and other lease information for the periods presented (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ Lease Costs 2021 ​ 2020 ​ Operating lease costs ​ $ 564 ​ $ 620 ​ Variable lease costs ​ ​ 174 ​ ​ 171 ​ Short-term lease costs ​ ​ 18 ​ ​ 15 ​ Total lease cost ​ $ 756 ​ $ 806 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ Operating lease cash flows – Fixed payments ​ $ 546 ​ $ 611 ​ Operating lease cash flows – Liability reduction ​ ​ 495 ​ ​ 530 ​ Right of use assets obtained during the period in exchange for operating lease liabilities ​ ​ 148 ​ ​ 128 ​ Weighted average lease term (in years) ​ ​ 5.83 ​ ​ 6.51 ​ Weighted average discount rate ​ ​ 2.80 % ​ 3.05 % ​ At March 31, 2021, the Company was obligated under noncancelable operating leases for office space and other commitments. Rent expense under operating leases, included in net occupancy and equipment expense, was ​ Rent commitments were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ 2021 Remainder of 2021 ​ $ 1,440 2022 ​ 1,604 2023 ​ ​ 1,409 2024 ​ ​ 974 2025 ​ ​ 840 Thereafter ​ ​ 1,792 Amounts representing interest ​ ​ (679) Present value of net future minimum lease payments ​ $ 7,380 ​

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Significant Accounting Policies
Nature of operations	Nature of Operations ​ First Busey Corporation, a Nevada corporation organized in 1980, is a $10.8 billion financial holding company headquartered in Champaign, Illinois. Our common stock is traded on The Nasdaq Global Select Market under the symbol “BUSE.” ​ The Company operates and reports its business in three segments: Banking, Remittance Processing, and Wealth Management. The Banking operating segment provides a full range of banking services to individual and corporate customers through the Company’s wholly-owned bank subsidiary, Busey Bank, with banking centers in Illinois; the St. Louis, Missouri metropolitan area; southwest Florida; and Indianapolis, Indiana. The Remittance Processing operating segment provides solutions for online bill payments, lockbox, and walk-in payments through the Company’s subsidiary, FirsTech. The Wealth Management operating segment provides a full range of asset management, investment, and fiduciary services to individuals, businesses and foundations, tax preparation, philanthropic advisory services, farms, and brokerage services.
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 our 2020 Annual Report. These interim unaudited consolidated financial statements serve to update our 2020 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.
COVID-19	COVID-19 ​ First Busey continues to operate as an essential community resource during these challenging and unprecedented times. Federal bank regulatory agencies, along with their state counterparts, have issued a steady stream of guidance responding to the COVID-19 pandemic and have taken a number of steps to help banks navigate the pandemic and mitigate its impact. ​ The Company remains vigilant, given that negative impacts of COVID-19, such as further margin compression and a deterioration in asset quality, could impact future quarters. ​ As part of the CARES Act, Congress appropriated approximately $349 billion for the creation of the PPP and then authorized a second phase for an additional $310 billion in PPP loans. The program provided payroll assistance for the nation’s nearly 30 million small businesses—and select nonprofits—in the form of government-guaranteed low-interest loans from the SBA. First Busey served as a bridge for the program, actively helping existing and new business clients sign up for this important financial resource. The Company originated a total of new and existing customers. As of March 31, 2021, the Company had received approximately million. Net fee income accretion recognized on these loans in the first quarter of 2021 was ​ On December 27, 2020, the Economic Aid Act extended the authority to make PPP loans through March 31, 2021, and revised certain PPP requirements. On March 30, 2021, the President signed the PPP Extension Act of 2021, which extended the PPP application deadline to May 31, 2021, or until funding is exhausted. As of March 31, 2021, the Company originated a total of new and existing customers. Net fee income accretion recognized on the loans related to this new round of PPP in the first quarter of 2021 was ​ At March 31, 2021, First Busey had $533.4 million in total PPP loans outstanding, with an amortized cost of $522.1 million, representing 3,441 customers.
Use of Estimates	Use of Estimates ​ In preparing the accompanying unaudited consolidated financial statements in conformity with GAAP, the Company’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 investment securities available for sale, fair value of assets acquired and liabilities assumed in business combinations, goodwill, income taxes, and the determination of the ACL.
Subsequent Events	Subsequent Events ​ The Company 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. There were no significant subsequent events for the quarter ended March 31, 2021, through the filing date of these unaudited consolidated financial statements.

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2021
Securities
Schedule of amortized cost, unrealized gains and losses and fair values of securities classified available for sale and held to maturity	The table below provides the amortized cost, unrealized gains and losses, and fair values of debt securities summarized by major category (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ Fair March 31, 2021: Cost Gains Losses ​ ACL Value U.S. Treasury securities ​ $ 23,514 ​ $ 243 ​ $ — ​ $ — ​ $ 23,757 Obligations of U.S. government corporations and agencies ​ 64,903 ​ 1,720 ​ (45) ​ ​ — ​ 66,578 Obligations of states and political subdivisions ​ 280,150 ​ 8,854 ​ (1,542) ​ ​ — ​ 287,462 Commercial mortgage-backed securities ​ ​ 499,996 ​ ​ 5,308 ​ ​ (6,786) ​ ​ — ​ ​ 498,518 Residential mortgage-backed securities ​ 1,786,062 ​ 18,587 ​ (18,329) ​ ​ — ​ 1,786,320 Corporate debt securities ​ 134,783 ​ 964 ​ (1,427) ​ ​ — ​ 134,320 Debt securities available for sale ​ $ 2,789,408 ​ $ 35,676 ​ $ (28,129) ​ $ — ​ $ 2,796,955 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ Fair December 31, 2020: Cost Gains Losses ​ ACL Value U.S. Treasury securities ​ $ 27,481 ​ $ 356 ​ $ — ​ $ — ​ $ 27,837 Obligations of U.S. government corporations and agencies ​ 67,406 ​ 2,162 ​ (49) ​ ​ — ​ 69,519 Obligations of states and political subdivisions ​ 292,940 ​ 11,779 ​ (8) ​ ​ — ​ 304,711 Commercial mortgage-backed securities ​ ​ 408,716 ​ ​ 10,212 ​ ​ (312) ​ ​ — ​ ​ 418,616 Residential mortgage-backed securities ​ 1,344,047 ​ 24,571 ​ (303) ​ ​ — ​ 1,368,315 Corporate debt securities ​ 70,953 ​ 1,237 ​ (1) ​ ​ — ​ 72,189 Debt securities available for sale ​ $ 2,211,543 ​ $ 50,317 ​ $ (673) ​ ​ — ​ $ 2,261,187
Schedule of amortized cost and fair value of debt securities available for sale and held to maturity by contractual maturity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ ​ Fair December 31, 2020: Cost Gains Losses ​ ACL Value U.S. Treasury securities ​ $ 27,481 ​ $ 356 ​ $ — ​ $ — ​ $ 27,837 Obligations of U.S. government corporations and agencies ​ 67,406 ​ 2,162 ​ (49) ​ ​ — ​ 69,519 Obligations of states and political subdivisions ​ 292,940 ​ 11,779 ​ (8) ​ ​ — ​ 304,711 Commercial mortgage-backed securities ​ ​ 408,716 ​ ​ 10,212 ​ ​ (312) ​ ​ — ​ ​ 418,616 Residential mortgage-backed securities ​ 1,344,047 ​ 24,571 ​ (303) ​ ​ — ​ 1,368,315 Corporate debt securities ​ 70,953 ​ 1,237 ​ (1) ​ ​ — ​ 72,189 Debt securities available for sale ​ $ 2,211,543 ​ $ 50,317 ​ $ (673) ​ ​ — ​ $ 2,261,187
Schedule of realized gains and losses related to sales of 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, ​ 2021 2020 Gross security gains ​ $ 25 ​ $ 1,561 Gross security (losses) ​ ​ — ​ ​ (5) Net gains (losses) on sales of debt securities (1) ​ $ 25 ​ $ 1,556 (1) Net gains (losses) on sales of securities reported on the unaudited Consolidated Statements of Income includes sales of equity securities, excluded in this table. ​
Schedule of securities with gross unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous loss position	The following information pertains to debt securities with gross unrealized losses, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ Fair Unrealized Fair Unrealized Fair Unrealized March 31, 2021: Value Losses Value Losses Value Losses Debt securities available for sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of U.S. government corporations and agencies ​ $ — ​ $ — ​ $ 4,695 ​ $ (45) ​ $ 4,695 ​ $ (45) Obligations of states and political subdivisions ​ ​ 58,555 ​ ​ (1,542) ​ ​ — ​ ​ — ​ ​ 58,555 ​ ​ (1,542) Commercial mortgage-backed securities ​ ​ 314,109 ​ ​ (6,786) ​ ​ — ​ ​ — ​ ​ 314,109 ​ ​ (6,786) Residential mortgage-backed securities ​ 1,019,462 ​ (18,325) ​ 352 ​ (4) ​ 1,019,814 ​ (18,329) Corporate debt securities ​ 95,164 ​ (1,427) ​ — ​ — ​ 95,164 ​ (1,427) Total temporarily impaired securities ​ $ 1,487,290 ​ $ (28,080) ​ $ 5,047 ​ $ (49) ​ $ 1,492,337 ​ $ (28,129) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ Fair Unrealized Fair Unrealized Fair Unrealized December 31, 2020: Value Losses Value Losses Value Losses Debt securities available for sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of U.S. government corporations and agencies ​ $ — ​ $ — ​ $ 4,957 ​ $ (49) ​ $ 4,957 ​ $ (49) Obligations of states and political subdivisions ​ ​ 762 ​ ​ (8) ​ ​ — ​ ​ — ​ ​ 762 ​ ​ (8) Commercial mortgage-backed securities ​ ​ 129,655 ​ ​ (312) ​ ​ — ​ ​ — ​ ​ 129,655 ​ ​ (312) Residential mortgage-backed securities ​ 89,997 ​ (300) ​ 139 ​ (3) ​ 90,136 ​ (303) Corporate debt securities ​ 1,499 ​ (1) ​ — ​ — ​ 1,499 ​ (1) Total temporarily impaired securities ​ $ 221,913 ​ $ (621) ​ $ 5,096 ​ $ (52) ​ $ 227,009 ​ $ (673)

Portfolio Loans (Tables)

Portfolio Loans (Tables)	3 Months Ended
	Mar. 31, 2021
Portfolio Loans
Distribution of portfolio loans	Distributions of portfolio loans are as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Commercial ​ $ 2,067,371 ​ $ 2,014,576 Commercial real estate ​ ​ 2,912,966 ​ ​ 2,892,535 Real estate construction ​ ​ 422,633 ​ ​ 461,786 Retail real estate ​ ​ 1,343,299 ​ ​ 1,407,852 Retail other ​ ​ 33,031 ​ ​ 37,428 Portfolio loans ​ $ 6,779,300 ​ $ 6,814,177 ​ ​ ​ ​ ​ ​ ​ ACL ​ ​ (93,943) ​ ​ (101,048) Portfolio loans, net ​ $ 6,685,357 ​ $ 6,713,129
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 of portfolio loans (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ ​ ​ Special ​ Substandard ​ Pass Watch Mention Substandard Non-accrual Commercial ​ $ 1,830,063 ​ $ 123,390 ​ $ 78,546 ​ $ 27,423 ​ $ 7,949 Commercial real estate ​ 2,400,446 ​ 407,244 ​ 68,900 ​ 31,212 ​ 5,164 Real estate construction ​ 400,306 ​ 19,918 ​ 9 ​ 2,400 ​ — Retail real estate ​ 1,318,247 ​ 9,879 ​ 2,376 ​ 4,302 ​ 8,495 Retail other ​ 32,933 ​ — ​ — ​ — ​ 98 Portfolio loans ​ $ 5,981,995 ​ $ 560,431 ​ $ 149,831 ​ $ 65,337 ​ $ 21,706 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Special ​ Substandard ​ Pass Watch Mention Substandard Non-accrual Commercial ​ $ 1,768,755 ​ $ 136,948 ​ $ 72,447 ​ $ 27,903 ​ $ 8,523 Commercial real estate ​ 2,393,372 ​ 383,277 ​ 75,486 ​ 34,897 ​ 5,503 Real estate construction ​ 434,681 ​ 24,481 ​ 77 ​ 2,546 ​ 1 Retail real estate ​ 1,382,616 ​ 10,264 ​ 2,471 ​ 3,702 ​ 8,799 Retail other ​ 37,324 ​ — ​ — ​ — ​ 104 Portfolio loans ​ $ 6,016,748 ​ $ 554,970 ​ $ 150,481 ​ $ 69,048 ​ $ 22,930
Risk grades of portfolio loans, further sorted by origination	Risk grades of portfolio loans, further sorted by origination year, are as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Risk Grade Ratings Term Loans Amortized Cost Basis by Origination Year ​ ​ Revolving ​ ​ ​ As of March 31, 2021 2021 2020 2019 2018 2017 ​ ​ Prior ​ ​ loans ​ ​ Total Commercial: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 388,147 ​ $ 536,074 ​ $ 131,127 ​ $ 97,322 ​ $ 88,238 ​ $ 126,916 ​ $ 462,239 ​ $ 1,830,063 Watch ​ ​ 4,830 ​ ​ 14,828 ​ ​ 18,085 ​ ​ 6,890 ​ ​ 9,185 ​ ​ 12,947 ​ ​ 56,625 ​ ​ 123,390 Special Mention ​ ​ 2,061 ​ ​ 4,241 ​ ​ 5,590 ​ ​ 8,369 ​ ​ 6,680 ​ ​ 18,831 ​ ​ 32,774 ​ ​ 78,546 Substandard ​ ​ 587 ​ ​ 8,912 ​ ​ 3,569 ​ ​ 2,993 ​ ​ 1,815 ​ ​ 125 ​ ​ 9,422 ​ ​ 27,423 Substandard non-accrual ​ ​ — ​ ​ 501 ​ ​ 2,392 ​ ​ 336 ​ ​ 2,168 ​ ​ 552 ​ ​ 2,000 ​ ​ 7,949 Total commercial ​ ​ 395,625 ​ ​ 564,556 ​ ​ 160,763 ​ ​ 115,910 ​ ​ 108,086 ​ ​ 159,371 ​ ​ 563,060 ​ ​ 2,067,371 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 195,095 ​ ​ 732,186 ​ ​ 462,732 ​ ​ 342,786 ​ ​ 315,383 ​ ​ 334,934 ​ ​ 17,330 ​ ​ 2,400,446 Watch ​ ​ 13,209 ​ ​ 91,440 ​ ​ 133,721 ​ ​ 89,517 ​ ​ 29,142 ​ ​ 48,557 ​ ​ 1,658 ​ ​ 407,244 Special Mention ​ ​ 19,920 ​ ​ 9,818 ​ ​ 7,902 ​ ​ 9,949 ​ ​ 7,172 ​ ​ 13,716 ​ ​ 423 ​ ​ 68,900 Substandard ​ ​ 2,500 ​ ​ 15,325 ​ ​ 3,557 ​ ​ 2,425 ​ ​ 4,400 ​ ​ 3,005 ​ ​ — ​ ​ 31,212 Substandard non-accrual ​ ​ — ​ ​ 784 ​ ​ 739 ​ ​ 821 ​ ​ 882 ​ ​ 1,938 ​ ​ — ​ ​ 5,164 Total commercial real estate ​ ​ 230,724 ​ ​ 849,553 ​ ​ 608,651 ​ ​ 445,498 ​ ​ 356,979 ​ ​ 402,150 ​ ​ 19,411 ​ ​ 2,912,966 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate construction: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 40,766 ​ ​ 167,230 ​ ​ 143,555 ​ ​ 39,297 ​ ​ 1,164 ​ ​ 1,680 ​ ​ 6,614 ​ ​ 400,306 Watch ​ ​ 2,079 ​ ​ 11,915 ​ ​ 3,653 ​ ​ 330 ​ ​ 1,785 ​ ​ 156 ​ ​ — ​ ​ 19,918 Special Mention ​ ​ — ​ ​ — ​ ​ 9 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 9 Substandard ​ ​ — ​ ​ 2,400 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,400 Substandard non-accrual ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Total real estate construction ​ ​ 42,845 ​ ​ 181,545 ​ ​ 147,217 ​ ​ 39,627 ​ ​ 2,949 ​ ​ 1,836 ​ ​ 6,614 ​ ​ 422,633 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 161,016 ​ ​ 207,536 ​ ​ 144,201 ​ ​ 118,052 ​ ​ 117,359 ​ ​ 351,700 ​ ​ 218,383 ​ ​ 1,318,247 Watch ​ ​ 189 ​ ​ 2,557 ​ ​ 2,040 ​ ​ 1,407 ​ ​ 291 ​ ​ 846 ​ ​ 2,549 ​ ​ 9,879 Special Mention ​ ​ 377 ​ ​ 33 ​ ​ — ​ ​ 18 ​ ​ — ​ ​ 1,948 ​ ​ — ​ ​ 2,376 Substandard ​ ​ 323 ​ ​ 882 ​ ​ 91 ​ ​ 56 ​ ​ 168 ​ ​ 2,497 ​ ​ 285 ​ ​ 4,302 Substandard non-accrual ​ ​ 483 ​ ​ 137 ​ ​ 76 ​ ​ 650 ​ ​ 1,128 ​ ​ 4,818 ​ ​ 1,203 ​ ​ 8,495 Total retail real estate ​ ​ 162,388 ​ ​ 211,145 ​ ​ 146,408 ​ ​ 120,183 ​ ​ 118,946 ​ ​ 361,809 ​ ​ 222,420 ​ ​ 1,343,299 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail other: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 2,014 ​ ​ 6,835 ​ ​ 8,062 ​ ​ 4,652 ​ ​ 1,949 ​ ​ 800 ​ ​ 8,621 ​ ​ 32,933 Watch ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Special Mention ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard non-accrual ​ ​ — ​ ​ 14 ​ ​ 7 ​ ​ 5 ​ ​ 14 ​ ​ 58 ​ ​ — ​ ​ 98 Total retail other ​ ​ 2,014 ​ ​ 6,849 ​ ​ 8,069 ​ ​ 4,657 ​ ​ 1,963 ​ ​ 858 ​ ​ 8,621 ​ ​ 33,031 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total portfolio loans ​ $ 833,596 ​ $ 1,813,648 ​ $ 1,071,108 ​ $ 725,875 ​ $ 588,923 ​ $ 926,024 ​ $ 820,126 ​ $ 6,779,300 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Risk Grade Ratings Term Loans Amortized Cost Basis by Origination Year ​ ​ Revolving ​ ​ ​ As of December 31, 2020 2020 2019 2018 2017 2016 ​ ​ Prior ​ ​ loans ​ ​ Total Commercial: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 812,536 ​ $ 158,307 ​ $ 107,565 ​ $ 93,190 ​ $ 61,847 ​ $ 79,970 ​ $ 455,340 ​ $ 1,768,755 Watch ​ ​ 16,544 ​ ​ 22,247 ​ ​ 14,954 ​ ​ 13,724 ​ ​ 2,577 ​ ​ 10,943 ​ ​ 55,959 ​ ​ 136,948 Special Mention ​ ​ 6,402 ​ ​ 2,671 ​ ​ 2,069 ​ ​ 7,164 ​ ​ 6,763 ​ ​ 13,733 ​ ​ 33,645 ​ ​ 72,447 Substandard ​ ​ 7,772 ​ ​ 3,791 ​ ​ 2,371 ​ ​ 1,939 ​ ​ 819 ​ ​ 1,233 ​ ​ 9,978 ​ ​ 27,903 Substandard non-accrual ​ ​ 150 ​ ​ 3,045 ​ ​ 451 ​ ​ 2,168 ​ ​ 641 ​ ​ 68 ​ ​ 2,000 ​ ​ 8,523 Total commercial ​ ​ 843,404 ​ ​ 190,061 ​ ​ 127,410 ​ ​ 118,185 ​ ​ 72,647 ​ ​ 105,947 ​ ​ 556,922 ​ ​ 2,014,576 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 717,559 ​ ​ 503,977 ​ ​ 360,573 ​ ​ 384,843 ​ ​ 180,555 ​ ​ 227,068 ​ ​ 18,797 ​ ​ 2,393,372 Watch ​ ​ 88,297 ​ ​ 110,526 ​ ​ 90,412 ​ ​ 33,734 ​ ​ 32,887 ​ ​ 27,023 ​ ​ 398 ​ ​ 383,277 Special Mention ​ ​ 16,490 ​ ​ 8,858 ​ ​ 10,490 ​ ​ 10,505 ​ ​ 7,102 ​ ​ 21,808 ​ ​ 233 ​ ​ 75,486 Substandard ​ ​ 17,445 ​ ​ 4,166 ​ ​ 1,491 ​ ​ 7,812 ​ ​ 2,111 ​ ​ 1,377 ​ ​ 495 ​ ​ 34,897 Substandard non-accrual ​ ​ 1,091 ​ ​ 776 ​ ​ 821 ​ ​ 882 ​ ​ 286 ​ ​ 1,647 ​ ​ — ​ ​ 5,503 Total commercial real estate ​ ​ 840,882 ​ ​ 628,303 ​ ​ 463,787 ​ ​ 437,776 ​ ​ 222,941 ​ ​ 278,923 ​ ​ 19,923 ​ ​ 2,892,535 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate construction: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 179,232 ​ ​ 171,663 ​ ​ 64,025 ​ ​ 1,468 ​ ​ 761 ​ ​ 1,444 ​ ​ 16,088 ​ ​ 434,681 Watch ​ ​ 18,485 ​ ​ 3,657 ​ ​ 337 ​ ​ 1,838 ​ ​ 164 ​ ​ ​ ​ ​ ​ ​ ​ 24,481 Special Mention ​ ​ 67 ​ ​ 10 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 77 Substandard ​ ​ 2,400 ​ ​ — ​ ​ — ​ ​ — ​ ​ 146 ​ ​ — ​ ​ — ​ ​ 2,546 Substandard non-accrual ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 1 ​ ​ — ​ ​ 1 Total real estate construction ​ ​ 200,184 ​ ​ 175,330 ​ ​ 64,362 ​ ​ 3,306 ​ ​ 1,071 ​ ​ 1,445 ​ ​ 16,088 ​ ​ 461,786 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 319,302 ​ ​ 162,711 ​ ​ 135,065 ​ ​ 136,427 ​ ​ 140,600 ​ ​ 257,147 ​ ​ 231,364 ​ ​ 1,382,616 Watch ​ ​ 2,715 ​ ​ 2,053 ​ ​ 1,396 ​ ​ 349 ​ ​ 579 ​ ​ 233 ​ ​ 2,939 ​ ​ 10,264 Special Mention ​ ​ 509 ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,962 ​ ​ — ​ ​ — ​ ​ 2,471 Substandard ​ ​ 899 ​ ​ 96 ​ ​ 56 ​ ​ 26 ​ ​ 727 ​ ​ 1,631 ​ ​ 267 ​ ​ 3,702 Substandard non-accrual ​ ​ 687 ​ ​ 78 ​ ​ 646 ​ ​ 1,147 ​ ​ 233 ​ ​ 4,815 ​ ​ 1,193 ​ ​ 8,799 Total retail real estate ​ ​ 324,112 ​ ​ 164,938 ​ ​ 137,163 ​ ​ 137,949 ​ ​ 144,101 ​ ​ 263,826 ​ ​ 235,763 ​ ​ 1,407,852 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retail other: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ ​ 8,357 ​ ​ 9,430 ​ ​ 5,600 ​ ​ 2,516 ​ ​ 691 ​ ​ 440 ​ ​ 10,290 ​ ​ 37,324 Watch ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Special Mention ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — Substandard non-accrual ​ ​ 14 ​ ​ 7 ​ ​ 5 ​ ​ 15 ​ ​ 5 ​ ​ 57 ​ ​ 1 ​ ​ 104 Total retail other ​ ​ 8,371 ​ ​ 9,437 ​ ​ 5,605 ​ ​ 2,531 ​ ​ 696 ​ ​ 497 ​ ​ 10,291 ​ ​ 37,428 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total portfolio loans ​ $ 2,216,953 ​ $ 1,168,069 ​ $ 798,327 ​ $ 699,747 ​ $ 441,456 ​ $ 650,638 ​ $ 838,987 ​ $ 6,814,177 ​
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) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ ​ Loans past due, still accruing ​ Non-accrual ​ 30-59 Days 60-89 Days 90+Days Loans Commercial ​ $ 52 ​ $ 2,614 ​ $ — ​ $ 7,949 Commercial real estate ​ ​ 4,377 ​ ​ — ​ ​ — ​ ​ 5,164 Real estate construction ​ — ​ — ​ — ​ — Retail real estate ​ ​ 2,248 ​ ​ 621 ​ ​ 1,149 ​ ​ 8,495 Retail other ​ 8 ​ 9 ​ — ​ 98 Past due and non-accrual loans ​ $ 6,685 ​ $ 3,244 ​ $ 1,149 ​ $ 21,706 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Loans past due, still accruing ​ Non-accrual ​ 30-59 Days 60-89 Days 90+Days Loans Commercial ​ $ 243 ​ $ — ​ $ — ​ $ 8,523 Commercial real estate ​ — ​ ​ — ​ ​ — ​ ​ 5,503 Real estate construction ​ 237 ​ 235 ​ — ​ 1 Retail real estate ​ 6,248 ​ ​ 400 ​ ​ 1,305 ​ ​ 8,799 Retail other ​ 66 ​ 149 ​ 66 ​ 104 Past due and non-accrual loans ​ $ 6,794 ​ $ 784 ​ $ 1,371 ​ $ 22,930
Summary of restructured loans	A summary of TDR loans is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 In compliance with modified terms ​ ​ 3,135 ​ ​ 3,814 30 – ​ ​ 164 ​ ​ 15 Included in non-performing loans ​ ​ 1,338 ​ ​ 1,249 TDR loans ​ $ 4,637 ​ $ 5,078
Schedule of details of impaired loans, segregated by category	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ Unpaid Amortized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ Cost ​ Amortized ​ Total ​ ​ ​ ​ Average ​ ​ Principal ​ with No ​ Cost ​ Amortized ​ Related ​ Amortized ​ Balance Allowance with Allowance Cost Allowance Cost Commercial ​ $ 16,008 ​ $ 2,987 ​ $ 4,817 ​ $ 7,804 ​ $ 2,483 ​ $ 7,524 Commercial real estate ​ 6,523 ​ ​ 5,552 ​ ​ — ​ 5,552 ​ — ​ 8,075 Real estate construction ​ 287 ​ 287 ​ — ​ 287 ​ — ​ 450 Retail real estate ​ 5,342 ​ 4,959 ​ 25 ​ 4,984 ​ 25 ​ 5,560 Retail other ​ — ​ — ​ — ​ — ​ — ​ — Loans evaluated individually ​ $ 28,160 ​ $ 13,785 ​ $ 4,842 ​ $ 18,627 ​ $ 2,508 ​ $ 21,609 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Unpaid Amortized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractual ​ Cost ​ Amortized ​ Total ​ ​ ​ ​ Average ​ ​ Principal ​ with No ​ Cost ​ Amortized ​ Related ​ Amortized ​ Balance Allowance with Allowance Cost Allowance Cost Commercial ​ $ 16,771 ​ $ 4,001 ​ $ 4,371 ​ $ 8,372 ​ $ 1,600 ​ $ 7,920 Commercial real estate ​ 7,406 ​ ​ 6,067 ​ ​ — ​ 6,067 ​ — ​ 9,349 Real estate construction ​ 292 ​ 292 ​ — ​ 292 ​ — ​ 581 Retail real estate ​ 5,873 ​ 5,490 ​ 25 ​ 5,515 ​ 25 ​ 7,439 Retail other ​ — ​ — ​ — ​ — ​ — ​ 10 Loans evaluated individually ​ $ 30,342 ​ $ 15,850 ​ $ 4,396 ​ $ 20,246 ​ $ 1,625 ​ $ 25,299 ​
Schedule of activity on the allowance for loan losses	The following table details activity in the ACL. Allocation of a portion of the ACL to one category does not preclude its availability to absorb losses in other categories (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of and for the Three Months Ended March 31, 2021 ​ ​ ​ ​ Commercial Real Estate Retail ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Real Estate Retail Other Total ACL beginning balance ​ $ 23,866 ​ $ 46,230 ​ $ 8,193 ​ $ 21,992 ​ $ 767 ​ $ 101,048 Provision for credit losses ​ (665) ​ (2,695) ​ (1,250) ​ (2,276) ​ 90 ​ (6,796) Charged-off ​ (262) ​ (303) ​ (209) ​ ​ (3) ​ (187) ​ (964) Recoveries ​ 86 ​ 74 ​ 145 ​ 265 ​ 85 ​ 655 ACL ending balance ​ $ 23,025 ​ $ 43,306 ​ $ 6,879 ​ $ 19,978 ​ $ 755 ​ $ 93,943 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of and for the Three Months Ended March 31, 2020 ​ ​ ​ ​ Commercial Real Estate Retail Real ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Estate Retail Other Total Beginning balance, prior to adoption of ASC ​ $ 18,291 ​ $ 21,190 ​ $ 3,204 ​ $ 10,495 ​ $ 568 ​ $ 53,748 Adoption of ASC ​ ​ 715 ​ ​ 9,306 ​ ​ 2,954 ​ ​ 3,292 ​ ​ 566 ​ ​ 16,833 Provision for credit losses ​ 5,673 ​ 6,526 ​ 889 ​ 4,037 ​ 91 ​ 17,216 Charged-off ​ (2,042) ​ (1,099) ​ — ​ ​ (708) ​ (299) ​ (4,148) Recoveries ​ 88 ​ 44 ​ 146 ​ 338 ​ 119 ​ 735 ACL ending balance ​ $ 22,725 ​ $ 35,967 ​ $ 7,193 ​ $ 17,454 ​ $ 1,045 ​ $ 84,384 ​
Schedule of allowance for loan losses and recorded investments in portfolio loans, by category	The following table presents the ACL and amortized cost of portfolio loans by category (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of March 31, 2021 ​ ​ ​ ​ Commercial Real Estate Retail Real ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Estate Retail Other Total ACL: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance attributed to: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 2,483 ​ $ — ​ $ — ​ $ 25 ​ $ — ​ $ 2,508 Loans collectively evaluated for impairment ​ 20,542 ​ 43,306 ​ 6,879 ​ 19,953 ​ 755 ​ 91,435 ACL ending balance ​ $ 23,025 ​ $ 43,306 ​ $ 6,879 ​ $ 19,978 ​ $ 755 ​ $ 93,943 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 7,804 ​ $ 3,644 ​ $ 287 ​ $ 4,613 ​ $ — ​ $ 16,348 Loans collectively evaluated for impairment ​ 2,059,567 ​ 2,907,414 ​ ​ 422,346 ​ 1,338,315 ​ 33,031 ​ 6,760,673 PCD loans evaluated for impairment ​ ​ — ​ ​ 1,908 ​ ​ — ​ ​ 371 ​ ​ — ​ ​ 2,279 Loans ending balance ​ $ 2,067,371 ​ $ 2,912,966 ​ $ 422,633 ​ $ 1,343,299 ​ $ 33,031 ​ $ 6,779,300 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ ​ ​ Commercial Real Estate Retail Real ​ ​ ​ ​ ​ ​ ​ Commercial Real Estate Construction Estate Retail Other Total ACL: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending balance attributed to: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 1,600 ​ $ — ​ $ — ​ $ 25 ​ $ — ​ $ 1,625 Loans collectively evaluated for impairment ​ 22,266 ​ 46,230 ​ 8,193 ​ 21,967 ​ 767 ​ 99,423 ACL ending balance ​ $ 23,866 ​ $ 46,230 ​ $ 8,193 ​ $ 21,992 ​ $ 767 ​ $ 101,048 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans individually evaluated for impairment ​ $ 8,372 ​ $ 4,161 ​ $ 292 ​ $ 5,149 ​ $ — ​ $ 17,974 Loans collectively evaluated for impairment ​ 2,006,204 ​ 2,886,468 ​ ​ 461,494 ​ 1,402,337 ​ 37,428 ​ 6,793,931 PCD loans evaluated for impairment ​ ​ — ​ ​ 1,906 ​ ​ — ​ ​ 366 ​ ​ — ​ ​ 2,272 Loans ending balance ​ $ 2,014,576 ​ $ 2,892,535 ​ $ 461,786 ​ $ 1,407,852 ​ $ 37,428 ​ $ 6,814,177

Deposits (Tables)

Deposits (Tables)	3 Months Ended
	Mar. 31, 2021
Deposits
Schedule of composition of deposits	The composition of deposits is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Demand deposits, noninterest-bearing ​ $ 2,859,492 ​ $ 2,552,039 Interest-bearing transaction deposits ​ 2,312,008 ​ 2,263,093 Saving deposits and money market deposits ​ 2,679,879 ​ ​ 2,743,369 Time deposits ​ 1,022,468 ​ 1,119,348 Total deposits ​ $ 8,873,847 ​ $ 8,677,849 Additional information about our deposits is as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Brokered savings deposits and money market deposits ​ $ 2,699 ​ $ 2,251 Brokered time deposits ​ ​ 5,259 ​ ​ 5,257 Aggregate amount of time deposits with a minimum denomination of $100,000 ​ ​ 502,968 ​ ​ 568,735 Aggregate amount of time deposits with a minimum denomination that meets or exceeds the FDIC insurance limit of $250,000 ​ ​ 155,401 ​ ​ 192,563
Schedule of maturities of time deposits	As of March 31, 2021, the scheduled maturities of time deposits are as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, Scheduled maturities of time deposits: ​ 2021 April 1, 2021 – March 31, 2022 $ 704,942 April 1, 2022 – March 31, 2023 ​ 175,252 April 1, 2023 – March 31, 2024 ​ 98,282 April 1, 2024 – March 31, 2025 ​ 29,736 April 1, 2025 – March 31, 2026 ​ 14,253 Thereafter ​ 3 Total time deposits ​ $ 1,022,468

Borrowings (Tables)

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2021
Borrowings
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, ​ ​ 2021 2020 Securities sold under agreements to repurchase ​ $ 210,132 ​ $ 175,614 ​ Weighted average rate for securities sold under agreements to repurchase ​ ​ 0.11 % ​ 0.13 %
Summary of long-term debt	Long-term debt is summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Notes payable, FHLB, original maturity of 5 years, collateralized by FHLB deposits, residential and commercial real estate loans and FHLB stock ​ $ 4,584 ​ $ 4,757
Schedule of unamortized debt issuance cost	Unamortized debt issuance costs related to senior notes and subordinated notes are presented in the following table (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ December 31, ​ 2021 2020 Unamortized debt issuance costs related to: ​ ​ ​ ​ ​ ​ Senior notes issued in 2017 ​ $ 157 ​ $ 191 Subordinated notes issued in 2017 ​ ​ 625 ​ ​ 651 Subordinated notes issued in 2020 ​ ​ 2,005 ​ ​ 2,123 Total unamortized debt issuance costs ​ $ 2,787 ​ $ 2,965

Regulatory Capital (Tables)

Regulatory Capital (Tables)	3 Months Ended
	Mar. 31, 2021
Regulatory Capital
Schedule of applicable holding company and bank regulatory capital requirements	The following tables summarize the applicable holding company and bank regulatory capital requirements (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Minimum ​ ​ ​ ​ ​ ​ ​ Minimum ​ To Be Well ​ ​ Actual ​ Capital Requirement ​ Capitalized ​ Amount Ratio Amount Ratio Amount Ratio As of March 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,265,926 17.39 % $ 582,526 8.00 % $ 728,157 10.00 % Busey Bank ​ $ 1,167,199 16.06 % $ 581,457 8.00 % $ 726,821 10.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,007,986 13.84 % $ 436,894 6.00 % $ 582,526 8.00 % Busey Bank ​ $ 1,094,260 15.06 % $ 436,093 6.00 % $ 581,457 8.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Equity Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 933,986 12.83 % $ 327,671 4.50 % $ 473,302 6.50 % Busey Bank ​ $ 1,094,260 15.06 % $ 327,070 4.50 % $ 472,434 6.50 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Average Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,007,986 9.85 % $ 409,360 4.00 % N/A N/A ​ Busey Bank ​ $ 1,094,260 10.71 % $ 408,522 4.00 % $ 510,652 5.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Minimum ​ ​ ​ ​ ​ ​ ​ ​ Minimum ​ To Be Well ​ ​ ​ Actual ​ Capital Requirement ​ Capitalized ​ ​ Amount Ratio Amount Ratio Amount Ratio As of December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,245,997 17.04 % $ 585,015 8.00 % $ 731,269 10.00 % Busey Bank ​ $ 1,131,875 15.50 % $ 584,082 8.00 % $ 730,103 10.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 983,033 13.44 % $ 438,761 6.00 % $ 585,015 8.00 % Busey Bank ​ $ 1,053,910 14.44 % $ 438,062 6.00 % $ 584,082 8.00 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Equity Tier 1 Capital (to Risk Weighted Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 909,033 12.43 % $ 329,071 4.50 % $ 475,325 6.50 % Busey Bank ​ $ 1,053,910 14.44 % $ 328,546 4.50 % $ 474,567 6.50 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tier 1 Capital (to Average Assets) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 983,033 9.79 % $ 401,717 4.00 % N/A N/A ​ Busey Bank ​ $ 1,053,910 10.52 % $ 400,581 4.00 % $ 500,727 5.00 %

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Stock-based Compensation
Schedule of status of and changes in the Company's stock option awards	A summary of the status of, and changes in, the Company's stock option awards for the three months ended March 31, 2021, follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ Average ​ Remaining ​ ​ ​ ​ ​ Exercise ​ Contractual ​ Shares Price Life Outstanding at beginning of period ​ 39,085 $ 23.53 ​ ​ 5.88 Exercised ​ — ​ — ​ ​ ​ Forfeited ​ — ​ ​ — ​ ​ ​ Expired ​ (5,279) ​ 23.53 ​ ​ ​ Outstanding at end of period ​ 33,806 $ 23.53 ​ 5.63 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at end of period ​ 33,806 $ 23.53 ​ 5.63
Summary of the changes in company deferred stock units	A summary of changes in the Company’s restricted stock unit and deferred stock unit awards for the three months ended March 31, 2021, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Director ​ Weighted- ​ ​ Restricted ​ Average ​ Deferred ​ Average ​ ​ Stock ​ Grant Date ​ Stock ​ Grant Date ​ Units Fair Value Units Fair Value Non-vested at beginning of period ​ 1,017,038 $ 23.87 ​ 34,263 $ 17.18 Granted ​ 212,426 ​ 24.54 ​ 33,288 ​ 24.54 Dividend equivalents earned ​ 11,310 ​ 20.67 ​ 1,172 ​ 20.67 Vested ​ — ​ — ​ (791) ​ 20.67 Forfeited ​ (13,422) ​ 26.98 ​ — ​ — Non-vested at end of period ​ 1,227,352 $ 23.93 ​ 67,932 $ 20.81 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at end of period ​ 1,227,352 $ 23.93 ​ 71,835 $ 24.30

Outstanding Commitments and C_2

Outstanding Commitments and Contingent Liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Outstanding Commitments and Contingent Liabilities
Schedule of contractual amount of exposure to off-balance-sheet risk	A summary of the contractual amount of the Company’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, ​ 2021 2020 Financial instruments whose contract amounts represent credit risk: ​ ​ ​ ​ ​ ​ Commitments to extend credit ​ $ 1,759,035 ​ $ 1,754,370 Standby letters of credit ​ 39,643 ​ 38,937

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2021
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 ​ ​ ​ March 31, ​ December 31, ​ ​ 2021 2020 Notional amount ​ $ 70,000 ​ $ 70,000 ​ Weighted average fixed pay rates ​ 1.80 % 1.80 % Weighted average variable 3-month LIBOR receive rates ​ ​ 0.18 % ​ 0.22 % Weighted average maturity, in years ​ ​ 2.61 yrs ​ 2.85 yrs Unrealized gains (losses), net of tax ​ $ (1,575) ​ $ (2,184) ​
Interest rate contract
Summary of gross gains and losses on derivative assets and liabilities recorded in non-interest income and expense in consolidated statements of income	The following table reflects the net gains (losses) recorded in accumulated other comprehensive income (loss) and the unaudited Consolidated Statements of Income relating to cash flow derivative instruments for the periods presented (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, Interest rate contracts 2021 2020 Gain (loss) recognized in OCI, net of tax ​ $ 410 ​ $ (2,237) (Gain) loss reclassified from OCI to interest expense, net of tax ​ ​ 199 ​ ​ (11) Net change in unrealized gains (losses) on cash flow hedges ​ $ 609 ​ $ (2,248)
Interest rate lock commitments and forward sales commitments
Summary of fair values of derivative assets and liabilities recorded in consolidated balance sheet	Amounts and fair values of mortgage banking derivatives included in the unaudited Consolidated Balance Sheets are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ December 31, 2020 ​ ​ ​ ​ ​ Notional ​ Fair ​ Notional ​ Fair Derivatives with positive fair value Location Amount Value Amount Value Interest rate lock commitments ​ Other assets ​ $ 24,142 ​ $ 474 ​ $ 45,004 ​ $ 1,201 Forward sales commitments ​ Other assets ​ ​ 7,035 ​ ​ 59 ​ ​ 978 ​ ​ 32 Mortgage banking derivatives recorded in other assets ​ $ 31,177 ​ $ 533 ​ $ 45,982 ​ $ 1,233 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives with negative fair value ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate lock commitments ​ Other liabilities ​ $ 931 ​ $ 2 ​ $ 118 ​ $ 1 Forward sales commitments ​ Other liabilities ​ ​ 55,454 ​ ​ 879 ​ ​ 84,964 ​ ​ 2,662 Mortgage banking derivatives recorded in other liabilities ​ $ 56,385 ​ $ 881 ​ $ 85,082 ​ $ 2,663
Summary of gross gains and losses on derivative assets and liabilities recorded in non-interest income and expense in consolidated statements of income	Net gains (losses) relating to these derivative instruments are summarized as follows for the periods presented (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ Location ​ 2021 ​ 2020 Interest rate lock commitments ​ Mortgage revenue ​ $ 472 ​ $ 4,849 Forward sales commitments ​ Mortgage revenue ​ (820) ​ ​ (7,047) Net gains (losses) ​ ​ ​ ​ $ (348) ​ $ (2,198)
Interest rate swap
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 unaudited Consolidated Balance Sheets are summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Asset ​ Derivative Liability ​ ​ Notional ​ Fair ​ Notional ​ Fair March 31, 2021 Amount Value Amount Value Interest rate swaps – pay floating, receive fixed ​ $ 308,178 ​ $ 18,881 ​ $ 93,069 ​ $ 3,209 Interest rate swaps – pay fixed, receive floating ​ ​ 93,069 ​ ​ 3,209 ​ ​ 308,178 ​ ​ 18,881 Derivatives not designated as hedging instruments ​ $ 401,247 ​ $ 22,090 ​ $ 401,247 ​ $ 22,090 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Asset ​ Derivative Liability ​ ​ Notional ​ Fair ​ Notional ​ Fair December 31, 2020 Amount Value Amount Value Interest rate swaps – pay floating, receive fixed ​ $ 394,954 ​ $ 32,685 ​ $ — ​ $ — Interest rate swaps – pay fixed, receive floating ​ ​ — ​ ​ — ​ ​ 394,954 ​ ​ 32,685 Derivatives not designated as hedging instruments ​ $ 394,954 ​ $ 32,685 ​ $ 394,954 ​ $ 32,685
Summary of gross gains and losses on derivative assets and liabilities recorded in non-interest income and expense in consolidated statements of income	Changes in fair value of these derivative assets and liabilities are recorded in non-interest expense in the unaudited Consolidated Statements of Income and summarized as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ Location 2021 2020 Interest rate swaps – pay floating, receive fixed ​ Non-interest expense ​ $ (10,595) ​ $ 23,478 Interest rate swaps – pay fixed, receive floating ​ Non-interest expense ​ ​ 10,595 ​ ​ (23,478) Net change in fair value of interest rate swaps ​ ​ ​ ​ $ — ​ $ —

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Measurements
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, 2021, and December 31, 2020, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total March 31, 2021 Inputs Inputs Inputs Fair Value Debt securities available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ — ​ $ 23,757 ​ $ — ​ $ 23,757 Obligations of U.S. government corporations and agencies ​ ​ — ​ ​ 66,578 ​ ​ — ​ ​ 66,578 Obligations of states and political subdivisions ​ ​ — ​ ​ 287,462 ​ ​ — ​ ​ 287,462 Commercial mortgage-backed securities ​ ​ — ​ ​ 498,518 ​ ​ — ​ ​ 498,518 Residential mortgage-backed securities ​ ​ — ​ ​ 1,786,320 ​ ​ — ​ ​ 1,786,320 Corporate debt securities ​ ​ — ​ ​ 134,320 ​ ​ — ​ ​ 134,320 Equity securities ​ ​ — ​ ​ 7,146 ​ ​ — ​ ​ 7,146 Loans held for sale ​ ​ — ​ ​ 38,272 ​ ​ — ​ ​ 38,272 Derivative assets ​ ​ — ​ ​ 22,623 ​ ​ — ​ ​ 22,623 Derivative liabilities ​ ​ — ​ ​ 25,173 ​ ​ — ​ ​ 25,173 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total December 31, 2020 Inputs Inputs Inputs Fair Value Debt securities available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ — ​ $ 27,837 ​ $ — ​ $ 27,837 Obligations of U.S. government corporations and agencies ​ ​ — ​ ​ 69,519 ​ ​ — ​ ​ 69,519 Obligations of states and political subdivisions ​ ​ — ​ ​ 304,711 ​ ​ — ​ ​ 304,711 Commercial mortgage-backed securities ​ ​ — ​ ​ 418,616 ​ ​ — ​ ​ 418,616 Residential mortgage-backed securities ​ ​ — ​ ​ 1,368,315 ​ ​ — ​ ​ 1,368,315 Corporate debt securities ​ ​ — ​ ​ 72,189 ​ ​ — ​ ​ 72,189 Equity securities ​ ​ — ​ ​ 5,530 ​ ​ — ​ ​ 5,530 Loans held for sale ​ ​ — ​ ​ 42,813 ​ ​ — ​ ​ 42,813 Derivative assets ​ ​ — ​ ​ 33,918 ​ ​ — ​ ​ 33,918 Derivative liabilities ​ ​ — ​ ​ 38,403 ​ ​ — ​ ​ 38,403
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 as of March 31, 2021, and December 31, 2020, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total March 31, 2021 Inputs Inputs Inputs Fair Value Loans evaluated individually ​ $ — ​ $ — ​ $ 2,334 ​ $ 2,334 OREO ​ — ​ — ​ 51 ​ 51 Bank property held for sale ​ — ​ — ​ 9,101 ​ 9,101 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 ​ Level 2 ​ Level 3 ​ Total December 31, 2020 Inputs Inputs Inputs Fair Value Loans evaluated individually ​ $ — ​ $ — ​ $ 2,771 ​ $ 2,771 OREO ​ — ​ — ​ 106 ​ 106 Bank property held for sale ​ ​ — ​ — ​ 10,676 ​ 10,676
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) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quantitative Information about Level 3 Fair Value Measurements ​ ​ Fair Value ​ Valuation ​ Unobservable ​ Range March 31, 2021 Estimate Techniques Input (Weighted Average) Loans evaluated individually ​ $ 2,334 ​ Appraisal of collateral ​ Appraisal adjustments ​ -42.8 % to -100.0 % (-51.8) % OREO ​ ​ 51 ​ Appraisal of collateral ​ Appraisal adjustments ​ -33.0 % to -100.0 % (-67.9) % Bank property held for sale ​ ​ 9,101 ​ Appraisal of collateral or real estate listing price ​ Appraisal adjustments ​ -6.2 % to -64.9 % (-41.3) % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loans evaluated individually ​ $ 2,771 ​ Appraisal of collateral ​ Appraisal adjustments ​ -30.0 % to -100.0 % (-37.0) % OREO ​ ​ 106 ​ Appraisal of collateral ​ Appraisal adjustments ​ -25.0 % to -100.0 % (-54.5) % Bank property held for sale ​ ​ 10,676 ​ Appraisal of collateral or real estate listing price ​ Appraisal adjustments ​ -6.2 % to -64.9 % (-42.8) %
Schedule of estimated fair values of financial instruments	Estimated fair values of financial instruments that are reported at amortized cost in the Company’s unaudited Consolidated Balance Sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2021 ​ December 31, 2020 ​ ​ Carrying Fair Carrying Fair ​ ​ Amount Value Amount Value Financial assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 1 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 404,802 ​ $ 404,802 ​ $ 688,537 ​ $ 688,537 Level 2 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accrued interest receivable ​ 31,876 ​ 31,876 ​ 33,240 ​ 33,240 Level 3 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Portfolio loans, net ​ 6,685,357 ​ 6,740,655 ​ 6,713,129 ​ 6,755,425 Mortgage servicing rights ​ ​ 10,409 ​ ​ 12,461 ​ ​ 10,912 ​ ​ 11,107 Other servicing rights ​ ​ 1,528 ​ ​ 2,055 ​ ​ 1,434 ​ ​ 1,966 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Level 2 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Time deposits ​ $ 1,022,468 ​ $ 1,031,778 ​ $ 1,119,348 ​ $ 1,132,107 Securities sold under agreements to repurchase ​ 210,132 ​ 210,132 ​ 175,614 ​ 175,614 Short-term borrowings ​ ​ 4,663 ​ ​ 4,669 ​ ​ 4,658 ​ ​ 4,661 Long-term debt ​ 4,584 ​ 4,806 ​ ​ 4,757 ​ 5,014 Junior subordinated debt owed to unconsolidated trusts ​ 71,509 ​ 56,511 ​ 71,468 ​ 59,943 Accrued interest payable ​ 5,671 ​ 5,671 ​ 3,401 ​ 3,401 Level 3 inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Senior notes, net of unamortized issuance costs ​ ​ 39,843 ​ ​ 40,066 ​ ​ 39,809 ​ ​ 40,104 Subordinated notes, net of unamortized issuance costs ​ ​ 182,370 ​ ​ 184,819 ​ ​ 182,226 ​ ​ 187,697

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share
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, ​ 2021 2020 Net income ​ $ 37,816 ​ $ 15,364 Shares: ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding ​ 54,471,860 ​ 54,661,787 Dilutive effect of outstanding options, warrants, and restricted stock units as determined by the application of the treasury stock method ​ 563,946 ​ 251,542 Weighted average common shares outstanding, as adjusted for diluted earnings per share calculation ​ 55,035,806 ​ 54,913,329 ​ ​ ​ ​ ​ ​ ​ Basic earnings per common share ​ $ 0.69 ​ $ 0.28 ​ ​ ​ ​ ​ ​ ​ Diluted earnings per common share ​ $ 0.69 ​ $ 0.28 ​ ​ ​ ​ ​ ​ ​ Common stock equivalents excluded from the earning per common share calculations because their effect would have been anti-dilutive ​ ​ 358,279 ​ ​ 244,242

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss).
Accumulated Other Comprehensive Income (Loss)	The following table represents changes in accumulated other comprehensive income (loss) by component, net of tax, for the periods below (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2021 ​ 2020 ​ ​ ​ Before Tax ​ ​ Tax Effect ​ ​ Net of Tax ​ ​ Before Tax ​ ​ Tax Effect ​ ​ Net of Tax Unrealized gains (losses) on debt securities available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at beginning of period ​ $ 49,644 ​ $ (14,151) ​ $ 35,493 ​ $ 21,192 ​ $ (6,032) ​ $ 15,160 Unrealized holding gains (losses) on debt securities available for sale, net ​ ​ (42,072) ​ ​ 11,993 ​ ​ (30,079) ​ ​ 30,086 ​ ​ (8,589) ​ ​ 21,497 Amounts reclassified from accumulated other comprehensive income, net ​ ​ (25) ​ ​ 7 ​ ​ (18) ​ ​ (1,556) ​ ​ 448 ​ ​ (1,108) Balance at end of period ​ $ 7,547 ​ $ (2,151) ​ $ 5,396 ​ $ 49,722 ​ $ (14,173) ​ $ 35,549 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized gains (losses) on cash flow hedges: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at beginning of period ​ $ (3,055) ​ $ 871 ​ $ (2,184) ​ $ (280) ​ $ 80 ​ $ (200) Unrealized holding gains (losses) on cash flow hedges, net ​ ​ 574 ​ ​ (164) ​ ​ 410 ​ ​ (3,129) ​ ​ 892 ​ ​ (2,237) Amounts reclassified from accumulated other comprehensive income, net ​ ​ 278 ​ ​ (79) ​ ​ 199 ​ ​ (15) ​ ​ 4 ​ ​ (11) Balance at end of period ​ $ (2,203) ​ $ 628 ​ $ (1,575) ​ $ (3,424) ​ $ 976 ​ $ (2,448) Total accumulated other comprehensive income (loss) ​ $ 5,344 ​ $ (1,523) ​ $ 3,821 ​ $ 46,298 ​ $ (13,197) ​ $ 33,101

Operating Segments and Relate_2

Operating Segments and Related Information (Tables)	3 Months Ended
	Mar. 31, 2021
Operating Segments and Related Information
Summary of information relating to operating segments	Following is a summary of selected financial information for the Company’s operating segments (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Goodwill ​ Total Assets ​ ​ As of ​ As of ​ ​ March 31, ​ December 31, ​ March 31, ​ December 31, ​ 2021 2020 2021 2020 Banking ​ $ 288,436 ​ $ 288,436 ​ $ 10,674,402 ​ $ 10,462,673 Remittance Processing ​ 8,992 ​ 8,992 ​ 46,765 ​ 46,553 Wealth Management ​ 14,108 ​ 14,108 ​ 50,392 ​ 46,504 Other ​ — ​ — ​ (11,996) ​ (11,683) Totals ​ $ 311,536 ​ $ 311,536 ​ $ 10,759,563 ​ $ 10,544,047 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2021 2020 Net interest income: ​ ​ ​ ​ ​ ​ Banking ​ $ 68,455 ​ $ 71,573 Remittance Processing ​ ​ 20 ​ ​ 19 Wealth Management ​ — ​ — Other ​ (3,582) ​ (2,159) Total net interest income ​ $ 64,893 ​ $ 69,433 ​ ​ ​ ​ ​ ​ ​ Non-interest income: ​ ​ ​ ​ ​ ​ Banking ​ $ 12,884 ​ $ 13,168 Remittance Processing ​ 4,861 ​ 4,069 Wealth Management ​ 12,587 ​ 11,709 Other ​ 1,113 ​ (1,429) Total non-interest income ​ $ 31,445 ​ $ 27,517 ​ ​ ​ ​ ​ ​ ​ Non-interest expense: ​ ​ ​ ​ ​ ​ Banking ​ $ 42,091 ​ $ 48,515 Remittance Processing ​ ​ 4,290 ​ ​ 2,903 Wealth Management ​ ​ 6,565 ​ ​ 6,974 Other ​ ​ 1,553 ​ ​ 2,122 Total non-interest expense ​ $ 54,499 ​ $ 60,514 ​ ​ ​ ​ ​ ​ ​ Income before income taxes: ​ ​ ​ ​ ​ ​ Banking ​ $ 46,044 ​ $ 19,010 Remittance Processing ​ ​ 591 ​ ​ 1,185 Wealth Management ​ ​ 6,022 ​ ​ 4,735 Other ​ ​ (4,022) ​ ​ (5,710) Total income before income taxes ​ $ 48,635 ​ $ 19,220 ​ ​ ​ ​ ​ ​ ​ Net income: ​ ​ ​ ​ ​ ​ Banking ​ $ 35,528 ​ $ 14,924 Remittance Processing ​ 429 ​ 860 Wealth Management ​ 4,682 ​ 3,599 Other ​ (2,823) ​ (4,019) Total net income ​ $ 37,816 ​ $ 15,364

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases
Schedule of lease costs and other lease information	​ The following tables represents lease costs and other lease information for the periods presented (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ Lease Costs 2021 ​ 2020 ​ Operating lease costs ​ $ 564 ​ $ 620 ​ Variable lease costs ​ ​ 174 ​ ​ 171 ​ Short-term lease costs ​ ​ 18 ​ ​ 15 ​ Total lease cost ​ $ 756 ​ $ 806 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ Operating lease cash flows – Fixed payments ​ $ 546 ​ $ 611 ​ Operating lease cash flows – Liability reduction ​ ​ 495 ​ ​ 530 ​ Right of use assets obtained during the period in exchange for operating lease liabilities ​ ​ 148 ​ ​ 128 ​ Weighted average lease term (in years) ​ ​ 5.83 ​ ​ 6.51 ​ Weighted average discount rate ​ ​ 2.80 % ​ 3.05 % ​
Schedule of future undiscounted lease payments	Rent commitments were as follows (dollars in thousands) ​ ​ ​ ​ ​ ​ ​ As of ​ ​ March 31, ​ 2021 Remainder of 2021 ​ $ 1,440 2022 ​ 1,604 2023 ​ ​ 1,409 2024 ​ ​ 974 2025 ​ ​ 840 Thereafter ​ ​ 1,792 Amounts representing interest ​ ​ (679) Present value of net future minimum lease payments ​ $ 7,380

Significant Accounting Polici_3

Significant Accounting Policies - Impact of new financial accounting standards (Details) $ in Billions	3 Months Ended
	Mar. 31, 2021USD ($)segment
Significant Accounting Policies
Value of company | $	$ 10.8
Number of operating segments | segment	3

Significant Accounting Polici_4

Significant Accounting Policies - COVID-19 Pandemic (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)customer	Dec. 31, 2020USD ($)
Paycheck Protection Program ("PPP")
Percentage of remaining loan maintains government guarantee	100.00%
Paycheck Protection Program
Paycheck Protection Program ("PPP")
Loans outstanding	$ 533.4
Amortized cost of the loans outstanding	$ 522.1	$ 446.4
Number of customers | customer	3,441
Paycheck Protection Program First Round [Member]
Paycheck Protection Program ("PPP")
Total loans	$ 749.4
New and existing customers | customer	4,569
Loan forgiveness	$ 478.5
Forgiveness application amount	131.6
Net fee income accretion	3.3
Paycheck Protection Program Second Round [Member]
Paycheck Protection Program ("PPP")
Total loans	$ 262.5
New and existing customers | customer	2,123
Net fee income accretion	$ 0.3

Acquisitions - The Banc Ed Corp

Acquisitions - The Banc Ed Corp. and Cummins-American Corp. (Details) $ / shares in Units, $ in Millions	Jan. 19, 2021USD ($)$ / shares	Mar. 31, 2021USD ($)	Jan. 15, 2021$ / shares
GSB
Merger agreement
Special cash dividend	$ 60
CAC
Merger agreement
Special cash dividend	$ 60
CAC
Merger agreement
Share consideration conversion ratio	444.4783
Per share cash consideration entitled (in dollars per share) | $ / shares	$ 27,969.67
Common stock Cash consideration	73.00%
Common stock share consideration	27.00%
Share price | $ / shares			$ 23.54
Business acquisition share price | $ / shares	$ 38,432.69
Market value of common stock issued	$ 190.8
Adjustments to the fair value assigned to various assets and liabilities	$ 169.6
Pre-tax acquisition expenses		$ 0.3

Securities - General Disclosure

Securities - General Disclosures (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)securityshares	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)securityshares
Debt securities available for sale
Amortized Cost	$ 2,789,408		$ 2,211,543
Gross Unrealized Gains	35,676		50,317
Gross Unrealized Losses	(28,129)		(673)
Fair Value	2,796,955		2,261,187
Debt securities available for sale, Amortized Cost
Due in one year or less	100,016
Due after one year through five years	291,357
Due after five years through ten years	303,453
Due after ten years	2,094,582
Amortized Cost	2,789,408		2,211,543
Debt securities available for sale, Fair Value
Due in one year or less	100,789
Due after one year through five years	297,624
Due after five years through ten years	309,672
Due after ten years	2,088,870
Fair Value	2,796,955		2,261,187
Realized gains and losses related to sales and calls of securities AFS
Gross security gains	25	$ 1,561
Gross security (losses)		(5)
Net gains (losses) on sales of debt securities	25	$ 1,556
Debt securities available for sale, Fair Value
Continuous unrealized losses existing for less than 12 months, gross	1,487,290		221,913
Continuous unrealized losses existing for greater than 12 months, gross	5,047		5,096
Total, gross	1,492,337		227,009
Debt securities available for sale, Unrealized Losses
Continuous unrealized losses existing for less than 12 months, gross	(28,080)		(621)
Continuous unrealized losses existing greater than 12 months, gross	(49)		(52)
Total, gross	$ (28,129)		$ (673)
Debt security portfolio | shares	1,108		1,114
Number of securities in unrealized loss position | security	192		23
Securities in unrealized loss position as a percentage of aggregate carrying value of investments	1.88%		0.30%
Collateral
Realized gains and losses related to sales and calls of securities AFS
Carrying amount of investment securities pledged as collateral	$ 562,600		$ 628,000
U.S. Treasury securities
Debt securities available for sale
Amortized Cost	23,514		27,481
Gross Unrealized Gains	243		356
Fair Value	23,757		27,837
Debt securities available for sale, Amortized Cost
Amortized Cost	23,514		27,481
Debt securities available for sale, Fair Value
Fair Value	23,757		27,837
Obligations of U.S. government corporations and agencies
Debt securities available for sale
Amortized Cost	64,903		67,406
Gross Unrealized Gains	1,720		2,162
Gross Unrealized Losses	(45)		(49)
Fair Value	66,578		69,519
Debt securities available for sale, Amortized Cost
Amortized Cost	64,903		67,406
Debt securities available for sale, Fair Value
Fair Value	66,578		69,519
Debt securities available for sale, Fair Value
Continuous unrealized losses existing for greater than 12 months, gross	4,695		4,957
Total, gross	4,695		4,957
Debt securities available for sale, Unrealized Losses
Continuous unrealized losses existing greater than 12 months, gross	(45)		(49)
Total, gross	(45)		(49)
Obligations of states and political subdivisions
Debt securities available for sale
Amortized Cost	280,150		292,940
Gross Unrealized Gains	8,854		11,779
Gross Unrealized Losses	(1,542)		(8)
Fair Value	287,462		304,711
Debt securities available for sale, Amortized Cost
Amortized Cost	280,150		292,940
Debt securities available for sale, Fair Value
Fair Value	287,462		304,711
Debt securities available for sale, Fair Value
Continuous unrealized losses existing for less than 12 months, gross	58,555		762
Total, gross	58,555		762
Debt securities available for sale, Unrealized Losses
Continuous unrealized losses existing for less than 12 months, gross	(1,542)		(8)
Total, gross	(1,542)		(8)
Commercial mortgage-backed securities
Debt securities available for sale
Amortized Cost	499,996		408,716
Gross Unrealized Gains	5,308		10,212
Gross Unrealized Losses	(6,786)		(312)
Fair Value	498,518		418,616
Debt securities available for sale, Amortized Cost
Amortized Cost	499,996		408,716
Debt securities available for sale, Fair Value
Fair Value	498,518		418,616
Debt securities available for sale, Fair Value
Continuous unrealized losses existing for less than 12 months, gross	314,109		129,655
Total, gross	314,109		129,655
Debt securities available for sale, Unrealized Losses
Continuous unrealized losses existing for less than 12 months, gross	(6,786)		(312)
Total, gross	(6,786)		(312)
Residential mortgage-backed securities
Debt securities available for sale
Amortized Cost	1,786,062		1,344,047
Gross Unrealized Gains	18,587		24,571
Gross Unrealized Losses	(18,329)		(303)
Fair Value	1,786,320		1,368,315
Debt securities available for sale, Amortized Cost
Amortized Cost	1,786,062		1,344,047
Debt securities available for sale, Fair Value
Fair Value	1,786,320		1,368,315
Debt securities available for sale, Fair Value
Continuous unrealized losses existing for less than 12 months, gross	1,019,462		89,997
Continuous unrealized losses existing for greater than 12 months, gross	352		139
Total, gross	1,019,814		90,136
Debt securities available for sale, Unrealized Losses
Continuous unrealized losses existing for less than 12 months, gross	(18,325)		(300)
Continuous unrealized losses existing greater than 12 months, gross	(4)		(3)
Total, gross	(18,329)		(303)
Corporate debt securities
Debt securities available for sale
Amortized Cost	134,783		70,953
Gross Unrealized Gains	964		1,237
Gross Unrealized Losses	(1,427)		(1)
Fair Value	134,320		72,189
Debt securities available for sale, Amortized Cost
Amortized Cost	134,783		70,953
Debt securities available for sale, Fair Value
Fair Value	134,320		72,189
Debt securities available for sale, Fair Value
Continuous unrealized losses existing for less than 12 months, gross	95,164		1,499
Total, gross	95,164		1,499
Debt securities available for sale, Unrealized Losses
Continuous unrealized losses existing for less than 12 months, gross	(1,427)		(1)
Total, gross	$ (1,427)		$ (1)

Portfolio Loans- Distribution o

Portfolio Loans- Distribution of portfolio loans (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Distributions of portfolio loans
Portfolio loans	$ 6,779,300	$ 6,814,177
ACL	(93,943)	(101,048)	$ (84,384)	$ (53,748)
Portfolio loans, net	6,685,357	6,713,129
Net deferred loan origination costs	3,400	2,400
Net accretable purchase accounting adjustments	9,000	10,900
Commercial Loans
Distributions of portfolio loans
Portfolio loans	2,067,371	2,014,576
ACL	(23,025)	(23,866)	(22,725)	(18,291)
Commercial Real Estate Loans
Distributions of portfolio loans
Portfolio loans	2,912,966	2,892,535
ACL	(43,306)	(46,230)	(35,967)	(21,190)
Real Estate Construction
Distributions of portfolio loans
Portfolio loans	422,633	461,786
ACL	(6,879)	(8,193)	(7,193)	(3,204)
Retail Real Estate
Distributions of portfolio loans
Portfolio loans	1,343,299	1,407,852
ACL	(19,978)	(21,992)	(17,454)	(10,495)
Retail Other
Distributions of portfolio loans
Portfolio loans	33,031	37,428
ACL	(755)	(767)	$ (1,045)	$ (568)
Paycheck Protection Program
Distributions of portfolio loans
Amortized cost of the loans outstanding	$ 522,100	$ 446,400

Portfolio Loans - Narrative (De

Portfolio Loans - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2021USD ($)	Mar. 31, 2021USD ($)loan	Mar. 31, 2020USD ($)loan
Distributions of portfolio loans
Loans classified as a TDR		$ 500	$ 500
TDRs subsequently classified as non-performing and had payment defaults | loan		0	0
Commercial Loans | Included in non-performing loans
Distributions of portfolio loans
Loans classified as a TDR		$ 500	$ 500
Performing loans classified as TDRs | loan		1	3
Commercial Real Estate Loans | Included in non-performing loans
Distributions of portfolio loans
Loans classified as a TDR			$ 700
Performing loans classified as TDRs | loan			1
Retail Real Estate | Included in non-performing loans
Distributions of portfolio loans
Loans classified as a TDR		$ 100
TDRs subsequently classified as non-performing and had payment defaults | loan		1
Residential real estate
Distributions of portfolio loans
Loans in the process of foreclosure	$ 400
Maximum | Commercial Real Estate Loans
Distributions of portfolio loans
Limit where loans are processed through an expedited underwriting process		$ 1,000
Watch | Commercial Loans
Distributions of portfolio loans
Limit above which loans are annually reviewed		1,000
Special Mention
Distributions of portfolio loans
Limit above which loans are annually reviewed		$ 350

Portfolio Loans - Summary of ri

Portfolio Loans - Summary of risk grades segregated by category (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans
Portfolio loans	$ 6,779,300	$ 6,814,177
Pass
Loans
Portfolio loans	5,981,995	6,016,748
Watch
Loans
Portfolio loans	560,431	554,970
Special Mention
Loans
Portfolio loans	149,831	150,481
Substandard
Loans
Portfolio loans	65,337	69,048
Substandard Non-accrual
Loans
Portfolio loans	21,706	22,930
Commercial
Loans
Portfolio loans	2,067,371	2,014,576
Commercial | Pass
Loans
Portfolio loans	1,830,063	1,768,755
Commercial | Watch
Loans
Portfolio loans	123,390	136,948
Commercial | Special Mention
Loans
Portfolio loans	78,546	72,447
Commercial | Substandard
Loans
Portfolio loans	27,423	27,903
Commercial | Substandard Non-accrual
Loans
Portfolio loans	7,949	8,523
Commercial real estate
Loans
Portfolio loans	2,912,966	2,892,535
Commercial real estate | Pass
Loans
Portfolio loans	2,400,446	2,393,372
Commercial real estate | Watch
Loans
Portfolio loans	407,244	383,277
Commercial real estate | Special Mention
Loans
Portfolio loans	68,900	75,486
Commercial real estate | Substandard
Loans
Portfolio loans	31,212	34,897
Commercial real estate | Substandard Non-accrual
Loans
Portfolio loans	5,164	5,503
Real estate construction
Loans
Portfolio loans	422,633	461,786
Real estate construction | Pass
Loans
Portfolio loans	400,306	434,681
Real estate construction | Watch
Loans
Portfolio loans	19,918	24,481
Real estate construction | Special Mention
Loans
Portfolio loans	9	77
Real estate construction | Substandard
Loans
Portfolio loans	2,400	2,546
Real estate construction | Substandard Non-accrual
Loans
Portfolio loans		1
Retail Real Estate
Loans
Portfolio loans	1,343,299	1,407,852
Retail Real Estate | Pass
Loans
Portfolio loans	1,318,247	1,382,616
Retail Real Estate | Watch
Loans
Portfolio loans	9,879	10,264
Retail Real Estate | Special Mention
Loans
Portfolio loans	2,376	2,471
Retail Real Estate | Substandard
Loans
Portfolio loans	4,302	3,702
Retail Real Estate | Substandard Non-accrual
Loans
Portfolio loans	8,495	8,799
Retail Other
Loans
Portfolio loans	33,031	37,428
Retail Other | Pass
Loans
Portfolio loans	32,933	37,324
Retail Other | Substandard Non-accrual
Loans
Portfolio loans	98	104
Commercial Loans
Loans
Portfolio loans	2,067,371	2,014,576
Commercial Real Estate Loans
Loans
Portfolio loans	2,912,966	2,892,535
Real Estate Construction
Loans
Portfolio loans	422,633	461,786
Retail Real Estate
Loans
Portfolio loans	1,343,299	1,407,852
Retail Other
Loans
Portfolio loans	$ 33,031	$ 37,428

Portfolio Loans and allowance f

Portfolio Loans and allowance for credit losses - Risk grades of portfolio loans by origination year (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans
2021	$ 833,596
2020	1,813,648	$ 2,216,953
2019	1,071,108	1,168,069
2018	725,875	798,327
2017	588,923	699,747
2016		441,456
Prior	926,024	650,638
Revolving loans	820,126	838,987
Ending balance	6,779,300	6,814,177
Pass
Loans
Ending balance	5,981,995	6,016,748
Watch
Loans
Ending balance	560,431	554,970
Special Mention
Loans
Ending balance	149,831	150,481
Substandard
Loans
Ending balance	65,337	69,048
Substandard Non-accrual
Loans
Ending balance	21,706	22,930
Commercial
Loans
2021	395,625
2020	564,556	843,404
2019	160,763	190,061
2018	115,910	127,410
2017	108,086	118,185
2016		72,647
Prior	159,371	105,947
Revolving loans	563,060	556,922
Ending balance	2,067,371	2,014,576
Commercial | Pass
Loans
2021	388,147
2020	536,074	812,536
2019	131,127	158,307
2018	97,322	107,565
2017	88,238	93,190
2016		61,847
Prior	126,916	79,970
Revolving loans	462,239	455,340
Ending balance	1,830,063	1,768,755
Commercial | Watch
Loans
2021	4,830
2020	14,828	16,544
2019	18,085	22,247
2018	6,890	14,954
2017	9,185	13,724
2016		2,577
Prior	12,947	10,943
Revolving loans	56,625	55,959
Ending balance	123,390	136,948
Commercial | Special Mention
Loans
2021	2,061
2020	4,241	6,402
2019	5,590	2,671
2018	8,369	2,069
2017	6,680	7,164
2016		6,763
Prior	18,831	13,733
Revolving loans	32,774	33,645
Ending balance	78,546	72,447
Commercial | Substandard
Loans
2021	587
2020	8,912	7,772
2019	3,569	3,791
2018	2,993	2,371
2017	1,815	1,939
2016		819
Prior	125	1,233
Revolving loans	9,422	9,978
Ending balance	27,423	27,903
Commercial | Substandard Non-accrual
Loans
2020	501	150
2019	2,392	3,045
2018	336	451
2017	2,168	2,168
2016		641
Prior	552	68
Revolving loans	2,000	2,000
Ending balance	7,949	8,523
Commercial real estate
Loans
2021	230,724
2020	849,553	840,882
2019	608,651	628,303
2018	445,498	463,787
2017	356,979	437,776
2016		222,941
Prior	402,150	278,923
Revolving loans	19,411	19,923
Ending balance	2,912,966	2,892,535
Commercial real estate | Pass
Loans
2021	195,095
2020	732,186	717,559
2019	462,732	503,977
2018	342,786	360,573
2017	315,383	384,843
2016		180,555
Prior	334,934	227,068
Revolving loans	17,330	18,797
Ending balance	2,400,446	2,393,372
Commercial real estate | Watch
Loans
2021	13,209
2020	91,440	88,297
2019	133,721	110,526
2018	89,517	90,412
2017	29,142	33,734
2016		32,887
Prior	48,557	27,023
Revolving loans	1,658	398
Ending balance	407,244	383,277
Commercial real estate | Special Mention
Loans
2021	19,920
2020	9,818	16,490
2019	7,902	8,858
2018	9,949	10,490
2017	7,172	10,505
2016		7,102
Prior	13,716	21,808
Revolving loans	423	233
Ending balance	68,900	75,486
Commercial real estate | Substandard
Loans
2021	2,500
2020	15,325	17,445
2019	3,557	4,166
2018	2,425	1,491
2017	4,400	7,812
2016		2,111
Prior	3,005	1,377
Revolving loans		495
Ending balance	31,212	34,897
Commercial real estate | Substandard Non-accrual
Loans
2020	784	1,091
2019	739	776
2018	821	821
2017	882	882
2016		286
Prior	1,938	1,647
Ending balance	5,164	5,503
Real estate construction
Loans
2021	42,845
2020	181,545	200,184
2019	147,217	175,330
2018	39,627	64,362
2017	2,949	3,306
2016		1,071
Prior	1,836	1,445
Revolving loans	6,614	16,088
Ending balance	422,633	461,786
Real estate construction | Pass
Loans
2021	40,766
2020	167,230	179,232
2019	143,555	171,663
2018	39,297	64,025
2017	1,164	1,468
2016		761
Prior	1,680	1,444
Revolving loans	6,614	16,088
Ending balance	400,306	434,681
Real estate construction | Watch
Loans
2021	2,079
2020	11,915	18,485
2019	3,653	3,657
2018	330	337
2017	1,785	1,838
2016		164
Prior	156
Ending balance	19,918	24,481
Real estate construction | Special Mention
Loans
2020		67
2019	9	10
Ending balance	9	77
Real estate construction | Substandard
Loans
2020	2,400	2,400
2016		146
Ending balance	2,400	2,546
Real estate construction | Substandard Non-accrual
Loans
Prior		1
Ending balance		1
Retail Real Estate
Loans
2021	162,388
2020	211,145	324,112
2019	146,408	164,938
2018	120,183	137,163
2017	118,946	137,949
2016		144,101
Prior	361,809	263,826
Revolving loans	222,420	235,763
Ending balance	1,343,299	1,407,852
Retail Real Estate | Pass
Loans
2021	161,016
2020	207,536	319,302
2019	144,201	162,711
2018	118,052	135,065
2017	117,359	136,427
2016		140,600
Prior	351,700	257,147
Revolving loans	218,383	231,364
Ending balance	1,318,247	1,382,616
Retail Real Estate | Watch
Loans
2021	189
2020	2,557	2,715
2019	2,040	2,053
2018	1,407	1,396
2017	291	349
2016		579
Prior	846	233
Revolving loans	2,549	2,939
Ending balance	9,879	10,264
Retail Real Estate | Special Mention
Loans
2021	377
2020	33	509
2018	18
2016		1,962
Prior	1,948
Ending balance	2,376	2,471
Retail Real Estate | Substandard
Loans
2021	323
2020	882	899
2019	91	96
2018	56	56
2017	168	26
2016		727
Prior	2,497	1,631
Revolving loans	285	267
Ending balance	4,302	3,702
Retail Real Estate | Substandard Non-accrual
Loans
2021	483
2020	137	687
2019	76	78
2018	650	646
2017	1,128	1,147
2016		233
Prior	4,818	4,815
Revolving loans	1,203	1,193
Ending balance	8,495	8,799
Retail Other
Loans
2021	2,014
2020	6,849	8,371
2019	8,069	9,437
2018	4,657	5,605
2017	1,963	2,531
2016		696
Prior	858	497
Revolving loans	8,621	10,291
Ending balance	33,031	37,428
Retail Other | Pass
Loans
2021	2,014
2020	6,835	8,357
2019	8,062	9,430
2018	4,652	5,600
2017	1,949	2,516
2016		691
Prior	800	440
Revolving loans	8,621	10,290
Ending balance	32,933	37,324
Retail Other | Substandard Non-accrual
Loans
2020	14	14
2019	7	7
2018	5	5
2017	14	15
2016		5
Prior	58	57
Revolving loans		1
Ending balance	98	104
Commercial Loans
Loans
Ending balance	2,067,371	2,014,576
Commercial Real Estate Loans
Loans
Ending balance	2,912,966	2,892,535
Real Estate Construction
Loans
Ending balance	422,633	461,786
Retail Real Estate
Loans
Ending balance	1,343,299	1,407,852
Retail Other
Loans
Ending balance	$ 33,031	$ 37,428

Portfolio Loans and allowance_2

Portfolio Loans and allowance for credit losses - Analysis of loans past due and still accruing or non-accrual status (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans past due
90+Days	$ 1,149	$ 1,371
Non-accrual Loans	21,706	22,930
30 to 59 Days
Loans past due
Loans past due, still accruing	6,685	6,794
60 to 89 Days
Loans past due
Loans past due, still accruing	3,244	784
Commercial
Loans past due
Non-accrual Loans	7,949	8,523
Commercial | 30 to 59 Days
Loans past due
Loans past due, still accruing	52	243
Commercial | 60 to 89 Days
Loans past due
Loans past due, still accruing	2,614
Commercial real estate
Loans past due
Non-accrual Loans	5,164	5,503
Commercial real estate | 30 to 59 Days
Loans past due
Loans past due, still accruing	4,377
Real estate construction
Loans past due
Non-accrual Loans		1
Real estate construction | 30 to 59 Days
Loans past due
Loans past due, still accruing		237
Real estate construction | 60 to 89 Days
Loans past due
Loans past due, still accruing		235
Retail Real Estate
Loans past due
90+Days	1,149	1,305
Non-accrual Loans	8,495	8,799
Retail Real Estate | 30 to 59 Days
Loans past due
Loans past due, still accruing	2,248	6,248
Retail Real Estate | 60 to 89 Days
Loans past due
Loans past due, still accruing	621	400
Retail Other
Loans past due
90+Days		66
Non-accrual Loans	98	104
Retail Other | 30 to 59 Days
Loans past due
Loans past due, still accruing	8	66
Retail Other | 60 to 89 Days
Loans past due
Loans past due, still accruing	$ 9	$ 149

Portfolio Loans - Summary of TD

Portfolio Loans - Summary of TDR loans (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Restructured loans
Total loans	$ 4,637	$ 5,078
In compliance with modified terms
Restructured loans
Total loans	3,135	3,814
30-89 days past due
Restructured loans
Total loans	164	15
Included in non-performing loans
Restructured loans
Total loans	$ 1,338	$ 1,249

Portfolio Loans - Loans identif

Portfolio Loans - Loans identified as impaired, segregated by category (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Loans identified as impaired
Unpaid Contractual Principal Balance	$ 28,160	$ 30,342
Recorded Investment with No Allowance	13,785	15,850
Recorded Investment with Allowance	4,842	4,396
Total Recorded Investment	18,627	20,246
Related Allowance	2,508	1,625
Average Recorded Investment	21,609	25,299
Collateral dependent loans secured by real estate or business assets	15,300
Commercial Loans
Loans identified as impaired
Unpaid Contractual Principal Balance	16,008	16,771
Recorded Investment with No Allowance	2,987	4,001
Recorded Investment with Allowance	4,817	4,371
Total Recorded Investment	7,804	8,372
Related Allowance	2,483	1,600
Average Recorded Investment	7,524	7,920
Commercial Real Estate Loans
Loans identified as impaired
Unpaid Contractual Principal Balance	6,523	7,406
Recorded Investment with No Allowance	5,552	6,067
Total Recorded Investment	5,552	6,067
Average Recorded Investment	8,075	9,349
Real Estate Construction
Loans identified as impaired
Unpaid Contractual Principal Balance	287	292
Recorded Investment with No Allowance	287	292
Total Recorded Investment	287	292
Average Recorded Investment	450	581
Retail Real Estate
Loans identified as impaired
Unpaid Contractual Principal Balance	5,342	5,873
Recorded Investment with No Allowance	4,959	5,490
Recorded Investment with Allowance	25	25
Total Recorded Investment	4,984	5,515
Related Allowance	25	25
Average Recorded Investment	$ 5,560	7,439
Retail Other
Loans identified as impaired
Average Recorded Investment		$ 10

Portfolio Loans - Activity in t

Portfolio Loans - Activity in the allowance for loan losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Activity in the allowance for loan losses
ACL beginning balance	$ 101,048	$ 53,748
Provision for loan losses	(6,796)	17,216
Charged-off	(964)	(4,148)
Recoveries	655	735
ACL ending balance	93,943	84,384
Allowance for loan losses Ending balance attributed to:
Loans individually evaluated for impairment			$ 2,508	$ 1,625
Loans collectively evaluated for impairment			91,435	99,423
Ending balance	101,048	84,384	93,943	101,048
Loans:
Loans individually evaluated for impairment			16,348	17,974
Loans collectively evaluated for impairment			6,760,673	6,793,931
PCD loans evaluated for impairment			2,279	2,272
Ending balance			6,779,300	6,814,177
Commercial Loans
Activity in the allowance for loan losses
ACL beginning balance	23,866	18,291
Provision for loan losses	(665)	5,673
Charged-off	(262)	(2,042)
Recoveries	86	88
ACL ending balance	23,025	22,725
Allowance for loan losses Ending balance attributed to:
Loans individually evaluated for impairment			2,483	1,600
Loans collectively evaluated for impairment			20,542	22,266
Ending balance	23,025	22,725	23,025	23,866
Loans:
Loans individually evaluated for impairment			7,804	8,372
Loans collectively evaluated for impairment			2,059,567	2,006,204
Ending balance			2,067,371	2,014,576
Commercial Real Estate Loans
Activity in the allowance for loan losses
ACL beginning balance	46,230	21,190
Provision for loan losses	(2,695)	6,526
Charged-off	(303)	(1,099)
Recoveries	74	44
ACL ending balance	43,306	35,967
Allowance for loan losses Ending balance attributed to:
Loans collectively evaluated for impairment			43,306	46,230
Ending balance	43,306	35,967	43,306	46,230
Loans:
Loans individually evaluated for impairment			3,644	4,161
Loans collectively evaluated for impairment			2,907,414	2,886,468
PCD loans evaluated for impairment			1,908	1,906
Ending balance			2,912,966	2,892,535
Real Estate Construction
Activity in the allowance for loan losses
ACL beginning balance	8,193	3,204
Provision for loan losses	(1,250)	889
Charged-off	(209)
Recoveries	145	146
ACL ending balance	6,879	7,193
Allowance for loan losses Ending balance attributed to:
Loans collectively evaluated for impairment			6,879	8,193
Ending balance	6,879	7,193	6,879	8,193
Loans:
Loans individually evaluated for impairment			287	292
Loans collectively evaluated for impairment			422,346	461,494
Ending balance			422,633	461,786
Retail Real Estate
Activity in the allowance for loan losses
ACL beginning balance	21,992	10,495
Provision for loan losses	(2,276)	4,037
Charged-off	(3)	(708)
Recoveries	265	338
ACL ending balance	19,978	17,454
Allowance for loan losses Ending balance attributed to:
Loans individually evaluated for impairment			25	25
Loans collectively evaluated for impairment			19,953	21,967
Ending balance	19,978	17,454	19,978	21,992
Loans:
Loans individually evaluated for impairment			4,613	5,149
Loans collectively evaluated for impairment			1,338,315	1,402,337
PCD loans evaluated for impairment			371	366
Ending balance			1,343,299	1,407,852
Retail Other
Activity in the allowance for loan losses
ACL beginning balance	767	568
Provision for loan losses	90	91
Charged-off	(187)	(299)
Recoveries	85	119
ACL ending balance	755	1,045
Allowance for loan losses Ending balance attributed to:
Loans collectively evaluated for impairment			755	767
Ending balance	$ 755	1,045	755	767
Loans:
Loans collectively evaluated for impairment			33,031	37,428
Ending balance			$ 33,031	$ 37,428
Cumulative Effect, Period of Adoption, Adjustment
Activity in the allowance for loan losses
ACL beginning balance		16,833
Allowance for loan losses Ending balance attributed to:
Ending balance		16,833
Cumulative Effect, Period of Adoption, Adjustment | Commercial Loans
Activity in the allowance for loan losses
ACL beginning balance		715
Allowance for loan losses Ending balance attributed to:
Ending balance		715
Cumulative Effect, Period of Adoption, Adjustment | Commercial Real Estate Loans
Activity in the allowance for loan losses
ACL beginning balance		9,306
Allowance for loan losses Ending balance attributed to:
Ending balance		9,306
Cumulative Effect, Period of Adoption, Adjustment | Real Estate Construction
Activity in the allowance for loan losses
ACL beginning balance		2,954
Allowance for loan losses Ending balance attributed to:
Ending balance		2,954
Cumulative Effect, Period of Adoption, Adjustment | Retail Real Estate
Activity in the allowance for loan losses
ACL beginning balance		3,292
Allowance for loan losses Ending balance attributed to:
Ending balance		3,292
Cumulative Effect, Period of Adoption, Adjustment | Retail Other
Activity in the allowance for loan losses
ACL beginning balance		566
Allowance for loan losses Ending balance attributed to:
Ending balance		$ 566

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deposits
Demand deposits, noninterest-bearing	$ 2,859,492	$ 2,552,039
Interest-bearing transaction deposits	2,312,008	2,263,093
Saving deposits and money market deposits	2,679,879	2,743,369
Time deposits	1,022,468	1,119,348
Total deposits	8,873,847	8,677,849
Brokered saving deposits and money market deposits	2,699	2,251
Brokered time deposits	5,259	5,257
Aggregate amount of time deposits with a minimum denomination of $100,000	502,968	568,735
Aggregate amount of time deposits with a minimum denomination that meets or exceeds the FDIC insurance limit of $250,000	155,401	192,563
Deposits
Total time deposits	1,022,468	1,119,348
Maturities of time deposits
April 1, 2021 - March 31, 2022	704,942
April 1, 2022 - March 31, 2023	175,252
April 1, 2023 - March 31, 2024	98,282
April 1, 2024 - March 31, 2025	29,736
April 1, 2025 - March 31, 2026	14,253
Thereafter	3
Total time deposits	$ 1,022,468	$ 1,119,348

Borrowings - Short-term borrowi

Borrowings - Short-term borrowings (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Maturity period
Securities sold under agreements to repurchase	$ 210,132	$ 175,614
Securities sold under agreements to repurchase, weighted average rate	0.11%	0.13%
Federal Funds Purchased	$ 0	$ 0
Short-term borrowings (FHLB advances)	$ 4,700	$ 4,700
Maximum maturity period of short-term debt	1 year
Minimum
Maturity period
Short-term borrowings, mature period	1 day
Maximum
Maturity period
Short-term borrowings, mature period	90 days

Borrowings - Amended and Restat

Borrowings - Amended and Restated Credit Agreement (Details) - Revolving loan facility - USD ($)	Apr. 21, 2021	Mar. 31, 2021	Dec. 31, 2020	Jan. 29, 2019
Borrowings
Maximum borrowing capacity				$ 20,000,000
Interest rate (as a percent)				1.75%
Term of the maturity extension	1 year
Outstanding amounts		$ 0	$ 0

Borrowings - Long-term Debt (De

Borrowings - Long-term Debt (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Long-term debt
Notes payable, FHLB, original maturity of 5 years, collateralized by FHLB deposits, residential and commercial real estate loans and FHLB stock.	$ 4,584	$ 4,757
FHLB advances
Long-term debt
Notes payable original maturity term	5 years	5 years
Interest rate (as a percent)	3.04%	3.04%

Borrowings - Senior notes and S

Borrowings - Senior notes and Subordinate Notes (Details) - USD ($) $ in Thousands	Jun. 01, 2020	May 25, 2017	Mar. 31, 2021	Dec. 31, 2020
Long-term debt
Unamortized debt issuance cost			$ 2,787	$ 2,965
3.75% notes maturing May 25, 2022 | Senior notes
Long-term debt
Issuance of debt		$ 40,000
Interest rate (as a percent)		3.75%
Unamortized debt issuance cost			157	191
4.75% notes maturing May 25, 2027 | Subordinated debt
Long-term debt
Issuance of debt		$ 60,000
Fixed payment term of note		5 years
Duration of fixed interest rate		5 years
Unamortized debt issuance cost			625	651
4.75% notes maturing May 25, 2027 | First Five Years | Subordinated debt
Long-term debt
Interest rate (as a percent)		4.75%
4.75% notes maturing May 25, 2027 | Three-month LIBOR | Subordinated debt
Long-term debt
Floating interest rate margin (as a percent)		2.919%
5.25% notes maturing June 1, 2030 | Subordinated debt
Long-term debt
Issuance of debt	$ 125,000
Duration of fixed interest rate	5 years
Floating interest rate margin (as a percent)	5.11%
Unamortized debt issuance cost			$ 2,005	$ 2,123
5.25% notes maturing June 1, 2030 | First Five Years | Subordinated debt
Long-term debt
Interest rate (as a percent)	5.25%

Regulatory Capital (Details)

Regulatory Capital (Details) $ in Thousands	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Total Capital (to Risk Weighted Assets), Amount
Actual, Amount	$ 1,265,926	$ 1,245,997
Minimum Capital Requirement, Amount	582,526	585,015
Minimum To Be Well Capitalized, Amount	$ 728,157	$ 731,269
Total Capital (to Risk Weighted Assets), Ratio
Actual, Ratio (as a percent)	17.39	17.04
Minimum Capital Requirement, Ratio (as a percent)	8	8
Minimum To Be Well Capitalized, Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), Amount
Actual, Amount	$ 1,007,986	$ 983,033
Minimum Capital Requirement, Amount	436,894	438,761
Minimum To Be Well Capitalized, Amount	$ 582,526	$ 585,015
Tier 1 Capital (to Risk Weighted Assets), Ratio
Actual, Ratio (as a percent)	13.84	13.44
Minimum Capital Requirement, Ratio (as a percent)	6	6
Minimum To Be Well Capitalized, Ratio (as a percent)	8	8
Common Equity Tier 1 Capital (to Risk Weighted Assets), Amount
Actual, Amount	$ 933,986	$ 909,033
Minimum Capital Requirement, Amount	327,671	329,071
Minimum To Be Well Capitalized, Amount	$ 473,302	$ 475,325
Common Equity Tier 1 Capital (to Risk Weighted Assets), Ratio
Actual, Ratio (as a percent)	12.83%	12.43%
Minimum Capital Requirement, Ratio (as a percent)	4.50%	4.50%
Minimum To Be Well Capitalized, Ratio (as a percent)	6.50%	6.50%
Tier 1 Capital (to Average Assets), Amount
Actual, Amount	$ 1,007,986	$ 983,033
Minimum Capital Requirement, Amount	$ 409,360	$ 401,717
Tier 1 Capital (to Average Assets), Ratio
Actual, Ratio (as a percent)	9.85	9.79
Minimum Capital Requirement, Ratio (as a percent)	4	4
Busey Bank
Total Capital (to Risk Weighted Assets), Amount
Actual, Amount	$ 1,167,199	$ 1,131,875
Minimum Capital Requirement, Amount	581,457	584,082
Minimum To Be Well Capitalized, Amount	$ 726,821	$ 730,103
Total Capital (to Risk Weighted Assets), Ratio
Actual, Ratio (as a percent)	16.06	15.50
Minimum Capital Requirement, Ratio (as a percent)	8	8
Minimum To Be Well Capitalized, Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), Amount
Actual, Amount	$ 1,094,260	$ 1,053,910
Minimum Capital Requirement, Amount	436,093	438,062
Minimum To Be Well Capitalized, Amount	$ 581,457	$ 584,082
Tier 1 Capital (to Risk Weighted Assets), Ratio
Actual, Ratio (as a percent)	15.06	14.44
Minimum Capital Requirement, Ratio (as a percent)	6	6
Minimum To Be Well Capitalized, Ratio (as a percent)	8	8
Common Equity Tier 1 Capital (to Risk Weighted Assets), Amount
Actual, Amount	$ 1,094,260	$ 1,053,910
Minimum Capital Requirement, Amount	327,070	328,546
Minimum To Be Well Capitalized, Amount	$ 472,434	$ 474,567
Common Equity Tier 1 Capital (to Risk Weighted Assets), Ratio
Actual, Ratio (as a percent)	15.06%	14.44%
Minimum Capital Requirement, Ratio (as a percent)	4.50%	4.50%
Minimum To Be Well Capitalized, Ratio (as a percent)	6.50%	6.50%
Tier 1 Capital (to Average Assets), Amount
Actual, Amount	$ 1,094,260	$ 1,053,910
Minimum Capital Requirement, Amount	408,522	400,581
Minimum To Be Well Capitalized, Amount	$ 510,652	$ 500,727
Tier 1 Capital (to Average Assets), Ratio
Actual, Ratio (as a percent)	10.71	10.52
Minimum Capital Requirement, Ratio (as a percent)	4	4
Minimum To Be Well Capitalized, Ratio (as a percent)	5	5

Stock-based Compensation (Detai

Stock-based Compensation (Details)	3 Months Ended
	Mar. 31, 2021shares
Performance based restricted stock unit
Share-based Compensation
Number of shares of common stock per award	1
Restricted stock unit
Share-based Compensation
Number of shares of common stock per award	1
Deferred stock units
Share-based Compensation
Number of shares of common stock per award	1
Vesting period	1 year
Settlement period	30 days
Minimum | Restricted stock unit
Share-based Compensation
Requisite service periods	1 year
Maximum | Restricted stock unit
Share-based Compensation
Requisite service periods	5 years

Stock-based Compensation - Awar

Stock-based Compensation - Award Status (Details) - Stock option awards - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Shares
Outstanding at beginning of year (in shares)	39,085
Expired (in shares)	(5,279)
Outstanding at end of year (in shares)	33,806	39,085
Exercisable at end of year (in shares)	33,806
Weighted-Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 23.53
Expired (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
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-Average Remaining Contractual Life, Outstanding	5 years 7 months 17 days	5 years 10 months 17 days
Weighted-Average Remaining Contractual Life, Exercisable	5 years 7 months 17 days

Stock-based Compensation - Opti

Stock-based Compensation - Options Outstanding (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Additional disclosures
Compensation expense recognized	$ 1,400,000	$ 1,100,000
Stock option awards
Additional disclosures
Compensation expense recognized	$ 0	$ 0

Stock-based Compensation - Rest

Stock-based Compensation - Restricted and Deferred Stock Units (Details) - USD ($)	Mar. 24, 2021	Mar. 31, 2021	Mar. 31, 2020
Additional disclosures
Compensation expense recognized		$ 1,400,000	$ 1,100,000
Restricted stock unit
Shares
Non-vested at beginning of year (in shares)		1,017,038
Granted (in shares)		212,426
Dividend equivalents earned (in shares)		11,310
Forfeited (in shares)		(13,422)
Non-vested at end of year (in shares)		1,227,352
Outstanding at end of year (in shares)		1,227,352
Weighted-Average Grant Date Fair Value
Non-vested at beginning of year (in dollars per share)		$ 23.87
Granted (in dollars per share)		24.54
Dividend equivalents earned (in dollars per share)		20.67
Forfeited (in dollars per share)		26.98
Non-vested at end of year (in dollars per share)		23.93
Outstanding at end of year (in dollars per share)		$ 23.93
Deferred stock units
Shares
Non-vested at beginning of year (in shares)		34,263
Granted (in shares)		33,288
Dividend equivalents earned (in shares)		1,172
Vested (in shares)		(791)
Non-vested at end of year (in shares)		67,932
Outstanding at end of year (in shares)		71,835
Weighted-Average Grant Date Fair Value
Non-vested at beginning of year (in dollars per share)		$ 17.18
Granted (in dollars per share)		24.54
Dividend equivalents earned (in dollars per share)		20.67
Vested (in dollars per share)		20.67
Non-vested at end of year (in dollars per share)		20.81
Outstanding at end of year (in dollars per share)		$ 24.30
Performance Stock units (PSUs)
Shares
Granted (in shares)		28,344
Additional disclosures
Compensation expense recognized		$ 700,000
Performance Stock units (PSUs) | Minimum
Additional disclosures
Vesting percentage (as a percent)		0.00%
Performance Stock units (PSUs) | Maximum
Shares
Granted (in shares)		39,682
Additional disclosures
Vesting percentage (as a percent)		140.00%
Market Based Performance Stock Units
Shares
Granted (in shares)		70,815
Additional disclosures
Compensation expense recognized		$ 1,700,000
Market Based Performance Stock Units | Minimum
Additional disclosures
Vesting percentage (as a percent)		0.00%
Market Based Performance Stock Units | Maximum
Shares
Granted (in shares)		113,304
Additional disclosures
Vesting percentage (as a percent)		160.00%
RSUs and DSUs
Additional disclosures
Amount of compensation cost to be recognized		$ 17,500,000
Period over which cost will be recognized		3 years 2 months 12 days
Stock option awards
Additional disclosures
Compensation expense recognized		$ 0	$ 0
2020 Equity Incentive Plan
Additional disclosures
Remaining shares available for issuance		1,094,149
2020 Equity Incentive Plan | Restricted stock unit | Management, Vice Chairman of Board
Shares
Granted (in shares)	212,426
Additional disclosures
Compensation expense recognized	$ 5,200,000
Vesting percentage (as a percent)	100.00%
2020 Equity Incentive Plan | Restricted stock unit | Management, Vice Chairman of Board | Minimum
Additional disclosures
Period over which cost will be recognized	1 year
2020 Equity Incentive Plan | Restricted stock unit | Management, Vice Chairman of Board | Maximum
Additional disclosures
Period over which cost will be recognized	5 years
2020 Equity Incentive Plan | Deferred stock units | Directors and Advisory Directors
Shares
Granted (in shares)	33,288
Additional disclosures
Compensation expense recognized	$ 800,000
Period over which cost will be recognized	1 year
Vesting percentage (as a percent)	100.00%

Outstanding Commitments and C_3

Outstanding Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Commitments to extend credit
Credit Commitments and Contingencies
Financial instruments whose contract amounts represent credit risk:	$ 1,759,035	$ 1,754,370
Standby letters of credit
Credit Commitments and Contingencies
Financial instruments whose contract amounts represent credit risk:	$ 39,643	$ 38,937

Derivative Financial Instrume_3

Derivative Financial Instruments - Interest Rate Swaps Designated as Cash Flow Hedges (Details) - Cash Flow Hedging - Interest rate swap - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Notional amount	$ 70,000	$ 70,000
Weighted average fixed pay rates	1.80%	1.80%
Weighted average variable 3 month LIBOR receive rates	0.18%	0.22%
Weighted average maturity in years	2 years 7 months 9 days	2 years 10 months 6 days
Unrealized gains (losses), net of tax	$ (1,575)	$ (2,184)
Interest income (expense) on swap transactions	300
Unrealized gain (loss) to be reclassified from OCI to interest expense during next twelve months	(300)
Other liabilities
Derivative [Line Items]
Fair value recorded in other liabilities	$ 2,200	$ 3,100

Derivative Financial Instrume_4

Derivative Financial Instruments - Net Gains (Losses) Recorded in Accumulated Other Comprehensive Income (Loss) (Details) - Interest rate contract - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Derivative [Line Items]
Cash pledged to secure obligations	$ 2,400		$ 3,200
Cash Flow Hedging
Derivative [Line Items]
Gain (loss) recognized in OCI, net of tax	410	$ (2,237)
(Gain) loss reclassified from OCI to interest expense, net of tax	199	(11)
Net change in unrealized gains (losses) on cash flow hedges	$ 609	$ (2,248)

Derivative Financial Instrume_5

Derivative Financial Instruments - Forward Sales Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Interest rate lock commitments | Other assets
Derivative Financial Instruments
Notional amount	$ 24,142		$ 45,004
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	474		1,201
Interest rate lock commitments | Other liabilities
Derivative Financial Instruments
Notional amount	931		118
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other liabilities	2		1
Forward sales commitments | Other assets
Derivative Financial Instruments
Notional amount	7,035		978
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	59		32
Forward sales commitments | Other liabilities
Derivative Financial Instruments
Notional amount	55,454		84,964
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other liabilities	879		2,662
Interest rate lock commitments and forward sales commitments | Designated as hedging instrument
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Net gains (losses)	(348)	$ (2,198)
Interest rate lock commitments and forward sales commitments | Other assets | Designated as hedging instrument
Derivative Financial Instruments
Notional amount	31,177		45,982
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	533		1,233
Interest rate lock commitments and forward sales commitments | Other liabilities | Designated as hedging instrument
Derivative Financial Instruments
Notional amount	56,385		85,082
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other liabilities	881		$ 2,663
Mortgage revenue | Interest rate lock commitments | Designated as hedging instrument
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross gains	472	4,849
Mortgage revenue | Forward sales commitments | Designated as hedging instrument
Gross gains and losses on derivative assets and liabilities recorded in Consolidated Statements of Income
Gross (losses)	$ (820)	$ (7,047)

Derivative Financial Instrume_6

Derivative Financial Instruments - Interest Rate Swaps Not Designated as Hedges (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Interest rate swap
Gains and losses on these derivative assets and liabilities recorded in non-interest expense in the unaudited Consolidated Statements of Income
Cash pledged to secure obligations	$ 25,600		$ 36,000
Interest rate swap | Not designated as hedging
Derivative Financial Instruments
Variable rate, commercial loans that are supported by the interest rate swap contracts	401,200		395,000
Notional Amount, Derivative Asset	401,247		394,954
Notional Amount, Derivative Liability	401,247		394,954
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	22,090		32,685
Fair value recorded in other liabilities	22,090		32,685
Interest rate swaps - pay floating, receive fixed | Not designated as hedging
Derivative Financial Instruments
Notional Amount, Derivative Asset	308,178		394,954
Notional Amount, Derivative Liability	93,069
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	18,881		32,685
Fair value recorded in other liabilities	3,209
Interest rate swaps - pay fixed, receive floating | Not designated as hedging
Derivative Financial Instruments
Notional Amount, Derivative Asset	93,069
Notional Amount, Derivative Liability	308,178		394,954
Fair values of derivative assets and liabilities recorded in consolidated balance sheets
Fair value recorded in other assets	3,209
Fair value recorded in other liabilities	18,881		$ 32,685
Non-interest expense | Interest rate swap
Gains and losses on these derivative assets and liabilities recorded in non-interest expense in the unaudited Consolidated Statements of Income
Gain (loss) pay, floating receive fixed	(10,595)	$ 23,478
Gain (loss) pay fixed receive floating	$ 10,595	$ (23,478)

Fair Value Measurements - Gener

Fair Value Measurements - General Disclosures (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	$ 2,796,955	$ 2,261,187
Equity securities	7,146	5,530
Loans held for sale, at fair value	38,272	42,813
U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	23,757	27,837
Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	66,578	69,519
Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	287,462	304,711
Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	498,518	418,616
Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	1,786,320	1,368,315
Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	134,320	72,189
Recurring basis
Financial assets and financial liabilities measured at fair value
Equity securities	7,146	5,530
Loans held for sale, at fair value	38,272	42,813
Recurring basis | Derivative assets
Financial assets and financial liabilities measured at fair value
Derivative asset	22,623	33,918
Recurring basis | Derivative liabilities
Financial assets and financial liabilities measured at fair value
Derivative liability	25,173	38,403
Recurring basis | U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	23,757	27,837
Recurring basis | Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	66,578	69,519
Recurring basis | Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	287,462	304,711
Recurring basis | Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	498,518	418,616
Recurring basis | Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	1,786,320	1,368,315
Recurring basis | Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	134,320	72,189
Recurring basis | Level 2
Financial assets and financial liabilities measured at fair value
Equity securities	7,146	5,530
Loans held for sale, at fair value	38,272	42,813
Recurring basis | Level 2 | Derivative assets
Financial assets and financial liabilities measured at fair value
Derivative asset	22,623	33,918
Recurring basis | Level 2 | Derivative liabilities
Financial assets and financial liabilities measured at fair value
Derivative liability	25,173	38,403
Recurring basis | Level 2 | U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	23,757	27,837
Recurring basis | Level 2 | Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	66,578	69,519
Recurring basis | Level 2 | Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	287,462	304,711
Recurring basis | Level 2 | Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	498,518	418,616
Recurring basis | Level 2 | Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	1,786,320	1,368,315
Recurring basis | Level 2 | Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	$ 134,320	$ 72,189

Fair Value Measurements - Addit

Fair Value Measurements - Additional Quantitative Information (Details) $ in Thousands	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually	$ 18,627	$ 20,246
Non-recurring basis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually	2,334	2,771
OREO	51	106
Bank property held for sale	9,101	10,676
Non-recurring basis | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually	2,334	2,771
OREO	51	106
Bank property held for sale	9,101	10,676
Non-recurring basis | Level 3 | Appraisal of collateral | Loans evaluated individually
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually	2,334	2,771
Non-recurring basis | Level 3 | Appraisal of collateral | OREO
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
OREO	51	106
Non-recurring basis | Level 3 | Appraisal of collateral or real estate listing price | Bank property held for sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank property held for sale	$ 9,101	$ 10,676
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral | Loans evaluated individually | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually (percent)	(42.8)	(30)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral | Loans evaluated individually | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually (percent)	(100)	(100)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral | Loans evaluated individually | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans evaluated individually (percent)	(51.8)	(37)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral | OREO | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
OREO (percent)	(33)	(25)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral | OREO | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
OREO (percent)	(100)	(100)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral | OREO | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
OREO (percent)	(67.9)	(54.5)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral or real estate listing price | Bank property held for sale | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank property held for sale (percent)	(6.2)	(6.2)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral or real estate listing price | Bank property held for sale | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank property held for sale (percent)	(64.9)	(64.9)
Appraisal adjustments | Non-recurring basis | Level 3 | Appraisal of collateral or real estate listing price | Bank property held for sale | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Bank property held for sale (percent)	(41.3)	(42.8)

Fair Value Measurements - Segre

Fair Value Measurements - Segregated by Level of Valuation Inputs (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financial assets:
Portfolio loans, net	$ 6,685,357	$ 6,713,129
Financial liabilities:
Short-term borrowings	4,663	4,658
Junior subordinated debt owed to unconsolidated trusts	71,509	71,468
Level 1 | Carrying Amount
Financial assets:
Cash and cash equivalents	404,802	688,537
Level 1 | Fair Value
Financial assets:
Cash and cash equivalents	404,802	688,537
Level 2 | Carrying Amount
Financial assets:
Accrued interest receivable	31,876	33,240
Financial liabilities:
Time deposits	1,022,468	1,119,348
Securities sold under agreements to repurchase	210,132	175,614
Short-term borrowings	4,663	4,658
Long-term debt	4,584	4,757
Junior subordinated debt owed to unconsolidated trusts	71,509	71,468
Accrued interest payable	5,671	3,401
Level 2 | Fair Value
Financial assets:
Accrued interest receivable	31,876	33,240
Financial liabilities:
Time deposits	1,031,778	1,132,107
Securities sold under agreements to repurchase	210,132	175,614
Short-term borrowings	4,669	4,661
Long-term debt	4,806	5,014
Junior subordinated debt owed to unconsolidated trusts	56,511	59,943
Accrued interest payable	5,671	3,401
Level 3 | Carrying Amount
Financial assets:
Portfolio loans, net	6,685,357	6,713,129
Mortgage servicing rights	10,409	10,912
Other servicing rights	1,528	1,434
Level 3 | Fair Value
Financial assets:
Portfolio loans, net	6,740,655	6,755,425
Mortgage servicing rights	12,461	11,107
Other servicing rights	2,055	1,966
Level 3 | Senior notes | Carrying Amount
Financial liabilities:
Long-term debt	39,843	39,809
Level 3 | Senior notes | Fair Value
Financial liabilities:
Long-term debt	40,066	40,104
Level 3 | Subordinated debt | Carrying Amount
Financial liabilities:
Long-term debt	182,370	182,226
Level 3 | Subordinated debt | Fair Value
Financial liabilities:
Long-term debt	$ 184,819	$ 187,697

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net income per share calculations for basic and diluted methods
Net income	$ 37,816	$ 15,364
Shares:
Weighted average common shares outstanding	54,471,860	54,661,787
Dilutive effect of outstanding options, warrants, and restricted stock units as determined by the application of the treasury stock method (in shares)	563,946	251,542
Weighted average common shares outstanding, as adjusted for diluted earnings per share calculation	55,035,806	54,913,329
Basic earnings per common share (in dollars per share)	$ 0.69	$ 0.28
Diluted earnings per common share (in dollars per share)	$ 0.69	$ 0.28
Common Stock
Shares:
Number of anti-dilutive securities (in shares)	358,279	244,242

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Changes in accumulated other comprehensive income (loss) by component, net of tax
Beginning balance	$ 1,270,069	$ 1,220,434
Unrealized gains (losses) on debt securities available for sale:
Unrealized holding gains (losses) on debt securities available for sale, Tax Effect	(11,993)	8,589
Unrealized holding gains (losses) on debt securities available for sale, Net of Tax	(30,079)	21,497
Amounts reclassified from accumulated other comprehensive income, Tax Effect	7	448
Amounts reclassified from accumulated other comprehensive income, Net of Tax	(18)	(1,108)
Unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) on cash flow hedges, Tax Effect	164	(892)
Unrealized holding gains (losses) on cash flow hedges, Net of Tax	410	(2,237)
Amounts reclassified from accumulated other comprehensive income, Tax Effect	79	(4)
Amounts reclassified from accumulated other comprehensive income, Net of Tax	199	(11)
Ending balance	1,265,822	1,217,585
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss) by component, net of tax
Beginning balance	33,309	14,960
Unrealized gains (losses) on cash flow hedges:
Accumulated other comprehensive income (loss) ending balance period, Before Tax	5,344	46,298
Accumulated other comprehensive income (loss) ending balance period, Tax Effect	(1,523)	(13,197)
Ending balance	3,821	33,101
Unrealized gains (losses) on debt securities available for sale
Changes in accumulated other comprehensive income (loss) by component, net of tax
Accumulated other comprehensive income (loss) beginning balance period, Before Tax	49,644	21,192
Accumulated other comprehensive income (loss) beginning balance period, Tax Effect	(14,151)	(6,032)
Beginning balance	35,493	15,160
Unrealized gains (losses) on debt securities available for sale:
Unrealized holding gains (losses) on debt securities available for sale, Before Tax	(42,072)	30,086
Unrealized holding gains (losses) on debt securities available for sale, Tax Effect	11,993	(8,589)
Unrealized holding gains (losses) on debt securities available for sale, Net of Tax	(30,079)	21,497
Amounts reclassified from accumulated other comprehensive income, Before Tax	(25)	(1,556)
Amounts reclassified from accumulated other comprehensive income, Tax Effect	7	448
Amounts reclassified from accumulated other comprehensive income, Net of Tax	(18)	(1,108)
Unrealized gains (losses) on cash flow hedges:
Accumulated other comprehensive income (loss) ending balance period, Before Tax	7,547	49,722
Accumulated other comprehensive income (loss) ending balance period, Tax Effect	(2,151)	(14,173)
Ending balance	5,396	35,549
Unrealized gains (losses) on cash flow hedges
Changes in accumulated other comprehensive income (loss) by component, net of tax
Accumulated other comprehensive income (loss) beginning balance period, Before Tax	(3,055)	(280)
Accumulated other comprehensive income (loss) beginning balance period, Tax Effect	871	80
Beginning balance	(2,184)	(200)
Unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) on cash flow hedges, Before Tax	574	(3,129)
Unrealized holding gains (losses) on cash flow hedges, Tax Effect	(164)	892
Unrealized holding gains (losses) on cash flow hedges, Net of Tax	410	(2,237)
Amounts reclassified from accumulated other comprehensive income, Before Tax	278	(15)
Amounts reclassified from accumulated other comprehensive income, Tax Effect	(79)	4
Amounts reclassified from accumulated other comprehensive income, Net of Tax	199	(11)
Accumulated other comprehensive income (loss) ending balance period, Before Tax	(2,203)	(3,424)
Accumulated other comprehensive income (loss) ending balance period, Tax Effect	628	976
Ending balance	$ (1,575)	$ (2,448)

Operating Segments and Relate_3

Operating Segments and Related Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)segment	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Operating Segments and Related Information
Number of reportable segments | segment	3
Number of operating segments | segment	3
Goodwill	$ 311,536		$ 311,536
Total Assets	10,759,563		10,544,047
Net interest income	64,893	$ 69,433
Non-interest income:	31,445	27,517
Non-interest expense:	54,499	60,514
Income before income taxes	48,635	19,220
Net income:	37,816	15,364
Operating segments | Banking
Operating Segments and Related Information
Goodwill	288,436		288,436
Total Assets	10,674,402		10,462,673
Net interest income	68,455	71,573
Non-interest income:	12,884	13,168
Non-interest expense:	42,091	48,515
Income before income taxes	46,044	19,010
Net income:	35,528	14,924
Operating segments | Remittance Processing
Operating Segments and Related Information
Goodwill	8,992		8,992
Total Assets	46,765		46,553
Net interest income	20	19
Non-interest income:	4,861	4,069
Non-interest expense:	4,290	2,903
Income before income taxes	591	1,185
Net income:	429	860
Operating segments | Wealth Management
Operating Segments and Related Information
Goodwill	14,108		14,108
Total Assets	50,392		46,504
Non-interest income:	12,587	11,709
Non-interest expense:	6,565	6,974
Income before income taxes	6,022	4,735
Net income:	4,682	3,599
Other
Operating Segments and Related Information
Total Assets	(11,996)		$ (11,683)
Net interest income	(3,582)	(2,159)
Non-interest income:	1,113	(1,429)
Non-interest expense:	1,553	2,122
Income before income taxes	(4,022)	(5,710)
Net income:	$ (2,823)	$ (4,019)

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Leases
Right of use assets	$ 7,333		$ 7,714
Lease liabilities	7,380		$ 7,757
Rent expense under operating leases, included in net occupancy and equipment expense	$ 756	$ 806

Leases - Lease Cost and Other L

Leases - Lease Cost and Other Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Lease Costs
Operating lease costs	$ 564	$ 620
Variable lease costs	174	171
Short-term lease costs	18	15
Total lease cost	756	806
Cash paid for amounts included in the measurement of lease liabilities
Operating lease cash flows - Fixed payments	546	611
Operating lease cash flows - Liability reduction	495	530
Right of use assets obtained during the period in exchange for operating lease liabilities	$ 148	$ 128
Weighted average lease term (in years)	5 years 9 months 29 days	6 years 6 months 3 days
Weighted average discount rate (in percent)	2.80%	3.05%

Leases - Future Rent Commitment

Leases - Future Rent Commitments (Details) $ in Thousands	Mar. 31, 2021USD ($)
Projected minimum rental payments under the terms of leases
Remainder of 2021	$ 1,440
2022	1,604
2023	1,409
2024	974
2025	840
Thereafter	1,792
Amounts representing interest	(679)
Present value of net future minimum lease payments	$ 7,380