XML 56 R46.htm IDEA: XBRL DOCUMENT
v3.23.3

Debt Securities - Additional Information (Details) $ in Thousands | Sep. 30, 2023 USD ($) security | Dec. 31, 2022 USD ($) security
--- | --- | ---
Available for Sale |  |
Debt securities with gross unrealized or unrecognized losses, fair value | $ | $ 2,171,839 | $ 2,439,533
Gross unrealized or unrecognized losses on debt securities | $ | $ 334,552 | $ 311,204
Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses | 15.40% | 12.80%
Count of debt securities | security | 1,001 | 1,091
Count of debt securities in an unrealized or unrecognized loss position | security | 982 | 1,032
Held to Maturity |  |
Debt securities with gross unrealized or unrecognized losses, fair value | $ | $ 701,676 | $ 785,295
Gross unrealized or unrecognized losses on debt securities | $ | $ 180,938 | $ 133,017
Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses | 25.80% | 16.90%
Count of debt securities | security | 55 | 55
Count of debt securities in an unrealized or unrecognized loss position | security | 55 | 55
Total |  |
Debt securities with gross unrealized or unrecognized losses, fair value | $ | $ 2,873,515 | $ 3,224,828
Gross unrealized or unrecognized losses on debt securities | $ | $ 515,490 | $ 444,221
Ratio of gross unrealized or unrecognized losses to debt securities with gross unrealized or unrecognized losses | 17.90% | 13.80%
Count of debt securities | security | 1,056 | 1,146
Count of debt securities in an unrealized or unrecognized loss position | security | 1,037 | 1,087

X
- Definition N/A + References No definition available. + Details
Name: | buse_AvailableForSaleAndHeldToMaturityDebtSecuritiesInUnrealizedLossPositionAbstract
Namespace Prefix: | buse_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition N/A + References No definition available. + Details
Name: | buse_AvailableForSaleDebtSecuritiesInUnrealizedLossPositionAbstract
Namespace Prefix: | buse_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the total number of securities in the investment portfolio which are in an unrealized loss position as a percentage of the aggregate carrying value. + References No definition available. + Details
Name: | buse_AvailableForSaleSecuritiesInUnrealizedLossPositionsAsPercentageOfAggregateCarryingValue
Namespace Prefix: | buse_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Gross total of unrealized losses on debt securities. + References No definition available. + Details
Name: | buse_DebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | buse_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of total debt securities. + References No definition available. + Details
Name: | buse_DebtSecuritiesFairValue
Namespace Prefix: | buse_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (held to maturity), in unrealized loss position. + References No definition available. + Details
Name: | buse_DebtSecuritiesHeldToMaturityUnrealizedLossPositionNumberOfPositions
Namespace Prefix: | buse_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total count of debt securities in an unrealized loss position. + References No definition available. + Details
Name: | buse_DebtSecuritiesUnrealizedLossPositionNumberOfPositions
Namespace Prefix: | buse_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the total number of securities in the investment portfolio which are in an unrealized loss position as a percentage of the aggregate carrying value. + References No definition available. + Details
Name: | buse_HeldForMaturitySecuritiesInUnrealizedLossPositionsAsPercentageOfAggregateCarryingValue
Namespace Prefix: | buse_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition N/A + References No definition available. + Details
Name: | buse_HeldToMaturityDebtSecuritiesInUnrealizedLossPositionAbstract
Namespace Prefix: | buse_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the total number of securities in the investment portfolio which are in an unrealized loss position as a percentage of the aggregate carrying value. + References No definition available. + Details
Name: | buse_SecuritiesInUnrealizedLossPositionsAsPercentageOfAggregateCarryingValue
Namespace Prefix: | buse_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total count of debt securities. + References No definition available. + Details
Name: | buse_TotalCountOfDebtSecurities
Namespace Prefix: | buse_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total count of available for sale debt securities. + References No definition available. + Details
Name: | buse_TotalCountOfDebtSecuritiesAvailableForSaleSecurities
Namespace Prefix: | buse_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total count of held to maturity debt securities. + References No definition available. + Details
Name: | buse_TotalCountOfDebtSecuritiesHeldToMaturity
Namespace Prefix: | buse_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479081/326-30-55-8 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-4 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-4 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-4 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-6 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-6 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant