XML 66 R54.htm IDEA: XBRL DOCUMENT
v3.24.1.u1

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

X
- Definition Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Writeoff + 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://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 2: 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=buse_CommercialAndIndustrialAndOtherCommercialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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