XML 110 R88.htm IDEA: XBRL DOCUMENT
v3.25.0.1

PORTFOLIO LOANS - Schedule of Risk Grades of Portfolio Loans, Further Sorted by Origination (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | $ 1,137,553 | $ 1,520,323
2024 / 2023, charge-off | 9 | 289
2023 / 2022 | 1,129,573 | 1,785,798
2023 /2022, charge-off | 15,011 | 76
2022 / 2021 | 1,485,489 | 1,552,072
2022 / 2021, charge-off | 254 | 592
2021 / 2020 | 1,250,313 | 705,335
2021 / 2020, charge-off | 3,099 | 34
2020 / 2019 | 619,027 | 468,659
2020 / 2019, charge-off | 4 | 391
Prior | 774,903 | 660,624
Prior, charge-off | 1,189 | 3,036
Revolving Loans | 1,300,229 | 958,223
Revolving Loans, charge-off | 0 | 0
Total | 7,697,087 | 7,651,034
Total | 19,566 | 4,418
Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 6,764,070 | 6,736,067
Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 756,610 | 747,122
Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 92,296 | 96,057
Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 62,023 | 64,347
Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 22,088 | 7,441
Commercial loans |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 5,552,288 | 5,635,048
Commercial loans | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 4,635,264 | 4,737,796
Commercial loans | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 747,202 | 735,978
Commercial loans | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 91,414 | 95,033
Commercial loans | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 59,480 | 62,552
Commercial loans | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 18,928 | 3,689
Commercial loans | C&I and other commercial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 376,534 | 394,854
2024 / 2023, charge-off | 0 | 284
2023 / 2022 | 206,282 | 295,539
2023 /2022, charge-off | 14,980 | 0
2022 / 2021 | 215,489 | 184,527
2022 / 2021, charge-off | 148 | 420
2021 / 2020 | 144,671 | 96,530
2021 / 2020, charge-off | 22 | 0
2020 / 2019 | 76,789 | 47,510
2020 / 2019, charge-off | 0 | 316
Prior | 144,014 | 169,911
Prior, charge-off | 303 | 1,409
Revolving Loans | 740,736 | 647,123
Revolving Loans, charge-off | 0 | 0
Total | 1,904,515 | 1,835,994
Total | 15,453 | 2,429
Commercial loans | C&I and other commercial | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 320,831 | 306,578
2023 / 2022 | 147,909 | 220,847
2022 / 2021 | 163,870 | 159,130
2021 / 2020 | 125,053 | 71,025
2020 / 2019 | 74,146 | 35,927
Prior | 117,234 | 143,078
Revolving Loans | 596,295 | 526,170
Total | 1,545,338 | 1,462,755
Commercial loans | C&I and other commercial | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 38,734 | 78,603
2023 / 2022 | 49,394 | 65,703
2022 / 2021 | 44,709 | 21,421
2021 / 2020 | 16,393 | 23,919
2020 / 2019 | 2,175 | 7,035
Prior | 20,964 | 21,293
Revolving Loans | 109,055 | 78,442
Total | 281,424 | 296,416
Commercial loans | C&I and other commercial | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 1,718 | 792
2023 / 2022 | 2,293 | 8,224
2022 / 2021 | 5,658 | 2,917
2021 / 2020 | 2,634 | 1,076
2020 / 2019 | 106 | 686
Prior | 2,540 | 3,274
Revolving Loans | 21,203 | 29,519
Total | 36,152 | 46,488
Commercial loans | C&I and other commercial | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 15,186 | 8,715
2023 / 2022 | 6,545 | 765
2022 / 2021 | 788 | 942
2021 / 2020 | 591 | 426
2020 / 2019 | 320 | 3,734
Prior | 2,424 | 1,859
Revolving Loans | 11,895 | 11,292
Total | 37,749 | 27,733
Commercial loans | C&I and other commercial | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 65 | 166
2023 / 2022 | 141 | 0
2022 / 2021 | 464 | 117
2021 / 2020 | 0 | 84
2020 / 2019 | 42 | 128
Prior | 852 | 407
Revolving Loans | 2,288 | 1,700
Total | 3,852 | 2,602
Commercial loans | CRE |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 467,816 | 578,595
2024 / 2023, charge-off | 0 | 0
2023 / 2022 | 488,528 | 882,350
2023 /2022, charge-off | 0 | 0
2022 / 2021 | 828,525 | 844,293
2022 / 2021, charge-off | 0 | 0
2021 / 2020 | 709,847 | 441,134
2021 / 2020, charge-off | 2,999 | 0
2020 / 2019 | 389,461 | 344,373
2020 / 2019, charge-off | 0 | 0
Prior | 358,936 | 226,537
Prior, charge-off | 315 | 953
Revolving Loans | 26,451 | 20,055
Revolving Loans, charge-off | 0 | 0
Total | 3,269,564 | 3,337,337
Total | 3,314 | 953
Commercial loans | CRE | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 291,503 | 395,644
2023 / 2022 | 354,591 | 824,506
2022 / 2021 | 755,266 | 720,052
2021 / 2020 | 645,994 | 399,195
2020 / 2019 | 356,867 | 271,078
Prior | 314,340 | 199,662
Revolving Loans | 25,457 | 16,893
Total | 2,744,018 | 2,827,030
Commercial loans | CRE | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 115,078 | 166,795
2023 / 2022 | 132,900 | 47,070
2022 / 2021 | 60,611 | 92,848
2021 / 2020 | 62,408 | 34,010
2020 / 2019 | 28,320 | 68,196
Prior | 38,733 | 19,396
Revolving Loans | 895 | 3,112
Total | 438,945 | 431,427
Commercial loans | CRE | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 39,252 | 14,313
2023 / 2022 | 643 | 10,507
2022 / 2021 | 8,020 | 12,446
2021 / 2020 | 1,395 | 4,968
2020 / 2019 | 4,165 | 3,297
Prior | 1,517 | 3,014
Revolving Loans | 49 | 0
Total | 55,041 | 48,545
Commercial loans | CRE | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 6,983 | 1,796
2023 / 2022 | 355 | 188
2022 / 2021 | 4,628 | 18,862
2021 / 2020 | 50 | 2,938
2020 / 2019 | 95 | 1,802
Prior | 4,346 | 3,856
Revolving Loans | 50 | 50
Total | 16,507 | 29,492
Commercial loans | CRE | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 15,000 | 47
2023 / 2022 | 39 | 79
2022 / 2021 | 0 | 85
2021 / 2020 | 0 | 23
2020 / 2019 | 14 | 0
Prior | 0 | 609
Revolving Loans | 0 | 0
Total | 15,053 | 843
Commercial loans | Real estate construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 185,219 | 213,138
2023 / 2022 | 140,905 | 132,868
2022 / 2021 | 12,205 | 85,593
2021 / 2020 | 25,233 | 2,938
2020 / 2019 | 2,213 | 1,364
Prior | 1,124 | 3,178
Revolving Loans | 11,310 | 22,638
Total | 378,209 | 461,717
Commercial loans | Real estate construction | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 159,825 | 204,952
2023 / 2022 | 134,450 | 128,462
2022 / 2021 | 12,205 | 85,086
2021 / 2020 | 24,781 | 2,616
2020 / 2019 | 2,213 | 1,323
Prior | 1,124 | 2,934
Revolving Loans | 11,310 | 22,638
Total | 345,908 | 448,011
Commercial loans | Real estate construction | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 20,170 | 2,859
2023 / 2022 | 6,455 | 4,406
2022 / 2021 | 0 | 507
2021 / 2020 | 208 | 322
2020 / 2019 | 0 | 41
Prior | 0 | 0
Revolving Loans | 0 | 0
Total | 26,833 | 8,135
Commercial loans | Real estate construction | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 0 |
2023 / 2022 | 0 |
2022 / 2021 | 0 |
2021 / 2020 | 221 |
2020 / 2019 | 0 |
Prior | 0 |
Revolving Loans | 0 |
Total | 221 | 0
Commercial loans | Real estate construction | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 5,224 | 5,327
2023 / 2022 | 0 | 0
2022 / 2021 | 0 | 0
2021 / 2020 | 0 | 0
2020 / 2019 | 0 | 0
Prior | 0 | 0
Revolving Loans | 0 | 0
Total | 5,224 | 5,327
Commercial loans | Real estate construction | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 0 | 0
2023 / 2022 | 0 | 0
2022 / 2021 | 0 | 0
2021 / 2020 | 23 | 0
2020 / 2019 | 0 | 0
Prior | 0 | 244
Revolving Loans | 0 | 0
Total | 23 | 244
Retail loans: |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 2,144,799 | 2,015,986
Retail loans: | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 2,128,806 | 1,998,271
Retail loans: | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 9,408 | 11,144
Retail loans: | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 882 | 1,024
Retail loans: | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 2,543 | 1,795
Retail loans: | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 3,160 | 3,752
Retail loans: | CRE |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 102,988 | 244,851
2024 / 2023, charge-off | 0 | 0
2023 / 2022 | 238,099 | 382,017
2023 /2022, charge-off | 0 | 5
2022 / 2021 | 371,259 | 414,578
2022 / 2021, charge-off | 0 | 0
2021 / 2020 | 358,351 | 158,032
2021 / 2020, charge-off | 0 | 29
2020 / 2019 | 148,260 | 70,815
2020 / 2019, charge-off | 0 | 72
Prior | 270,229 | 260,142
Prior, charge-off | 168 | 301
Revolving Loans | 207,271 | 190,020
Revolving Loans, charge-off | 0 | 0
Total | 1,696,457 | 1,720,455
Total | 168 | 407
Retail loans: | CRE | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 101,582 | 243,400
2023 / 2022 | 237,306 | 376,922
2022 / 2021 | 366,820 | 411,723
2021 / 2020 | 354,380 | 156,762
2020 / 2019 | 147,236 | 70,099
Prior | 267,431 | 256,571
Revolving Loans | 205,885 | 187,420
Total | 1,680,640 | 1,702,897
Retail loans: | CRE | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 1,255 | 1,096
2023 / 2022 | 550 | 4,137
2022 / 2021 | 2,733 | 2,442
2021 / 2020 | 3,377 | 954
2020 / 2019 | 872 | 536
Prior | 124 | 234
Revolving Loans | 497 | 1,745
Total | 9,408 | 11,144
Retail loans: | CRE | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 151 | 286
2023 / 2022 | 0 | 358
2022 / 2021 | 344 | 0
2021 / 2020 | 0 | 0
2020 / 2019 | 0 | 0
Prior | 372 | 380
Revolving Loans | 15 | 0
Total | 882 | 1,024
Retail loans: | CRE | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 0 | 69
2023 / 2022 | 243 | 72
2022 / 2021 | 1,018 | 292
2021 / 2020 | 503 | 49
2020 / 2019 | 0 | 80
Prior | 776 | 997
Revolving Loans | 3 | 236
Total | 2,543 | 1,795
Retail loans: | CRE | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 0 | 0
2023 / 2022 | 0 | 528
2022 / 2021 | 344 | 121
2021 / 2020 | 91 | 267
2020 / 2019 | 152 | 100
Prior | 1,526 | 1,960
Revolving Loans | 871 | 619
Total | 2,984 | 3,595
Retail loans: | Retail other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 4,996 | 88,885
2024 / 2023, charge-off | 9 | 5
2023 / 2022 | 55,759 | 93,024
2023 /2022, charge-off | 31 | 71
2022 / 2021 | 58,011 | 23,081
2022 / 2021, charge-off | 106 | 172
2021 / 2020 | 12,211 | 6,701
2021 / 2020, charge-off | 78 | 5
2020 / 2019 | 2,304 | 4,597
2020 / 2019, charge-off | 4 | 3
Prior | 600 | 856
Prior, charge-off | 403 | 373
Revolving Loans | 314,461 | 78,387
Revolving Loans, charge-off | 0 | 0
Total | 448,342 | 295,531
Total | 631 | 629
Retail loans: | Retail other | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 4,996 | 88,885
2023 / 2022 | 55,665 | 92,931
2022 / 2021 | 57,944 | 23,019
2021 / 2020 | 12,207 | 6,701
2020 / 2019 | 2,304 | 4,597
Prior | 589 | 854
Revolving Loans | 314,461 | 78,387
Total | 448,166 | 295,374
Retail loans: | Retail other | Watch |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 0 | 0
Retail loans: | Retail other | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 0 | 0
Retail loans: | Retail other | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 0 | 0
Retail loans: | Retail other | Substandard Non-accrual |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
2024 / 2023 | 0 | 0
2023 / 2022 | 94 | 93
2022 / 2021 | 67 | 62
2021 / 2020 | 4 | 0
2020 / 2019 | 0 | 0
Prior | 11 | 2
Revolving Loans | 0 | 0
Total | $ 176 | $ 157

X
- Definition Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Write off + References No definition available. + Details
Name: | buse_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossWriteOff
Namespace Prefix: | buse_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable originated more than five years before current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, of financing receivable that can be withdrawn, repaid, and redrawn. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestRevolving
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable that can be withdrawn, repaid, and redrawn. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable originated four years before current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable originated three years before current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated in current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable originated in current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable originated two years before current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of writeoff of financing receivable originated in fiscal year before current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 29 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-29 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=buse_WatchListMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_DoubtfulMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=buse_CommercialAndIndustrialAndOtherCommercialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |