XML 91 R80.htm IDEA: XBRL DOCUMENT
v3.25.3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring and Nonrecurring basis (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
Assets |  |  |  |  |
Investment securities available for sale | $ 1,378,907 |  | $ 1,378,907 |  | $ 1,207,574
Equity securities | 4,214 |  | 4,214 |  | 4,792
U.S. government sponsored entities and U.S. agency securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 15,123 |  | 15,123 |  | 20,141
Mortgage-backed securities - non-agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 93,860 |  | 93,860 |  | 101,012
Asset-backed student loans |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 43,258 |  | 43,258 |  | 49,973
State and municipal securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 73,290 |  | 73,290 |  | 69,061
Collateralized loan obligations |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 47,845 |  | 47,845 |  | 40,450
Corporate securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 56,728 |  | 56,728 |  | 79,881
Recurring |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale | 7,535 |  | 7,535 |  | 8,228
Credit enhancement asset | 5,765 |  | 5,765 |  | 16,804
Derivative assets | $ 3,910 |  | $ 3,910 |  | $ 3,837
Derivative Asset, Statement of Financial Position [Extensible Enumeration] | Other assets |  | Other assets |  | Other assets
Total | $ 1,400,331 |  | $ 1,400,331 |  | $ 1,241,235
Liabilities |  |  |  |  |
Derivative liabilities | 6,309 |  | 6,309 |  | 5,655
Total | 6,309 |  | 6,309 |  | 5,655
Recurring | U.S. government sponsored entities and U.S. agency securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 15,123 |  | 15,123 |  | 20,141
Recurring | Mortgage-backed securities - agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 1,048,803 |  | 1,048,803 |  | 847,056
Recurring | Mortgage-backed securities - non-agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 93,860 |  | 93,860 |  | 101,012
Recurring | Asset-backed student loans |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 43,258 |  | 43,258 |  | 49,973
Recurring | State and municipal securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 73,290 |  | 73,290 |  | 69,061
Recurring | Collateralized loan obligations |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 47,845 |  | 47,845 |  | 40,450
Recurring | Corporate securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 56,728 |  | 56,728 |  | 79,881
Recurring | Equity securities |  |  |  |  |
Assets |  |  |  |  |
Equity securities | 4,214 |  | 4,214 |  | 4,792
Recurring | Level 1 |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale | 0 |  | 0 |  | 0
Credit enhancement asset | 0 |  | 0 |  | 0
Derivative assets | 0 |  | 0 |  | 0
Total | 4,214 |  | 4,214 |  | 4,792
Liabilities |  |  |  |  |
Derivative liabilities | 0 |  | 0 |  | 0
Total | 0 |  | 0 |  | 0
Recurring | Level 1 | U.S. government sponsored entities and U.S. agency securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | Mortgage-backed securities - agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | Mortgage-backed securities - non-agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | Asset-backed student loans |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | State and municipal securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | Collateralized loan obligations |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | Corporate securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 1 | Equity securities |  |  |  |  |
Assets |  |  |  |  |
Equity securities | 4,214 |  | 4,214 |  | 4,792
Recurring | Level 2 |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale | 7,535 |  | 7,535 |  | 8,228
Credit enhancement asset | 0 |  | 0 |  | 0
Derivative assets | 3,910 |  | 3,910 |  | 3,837
Total | 1,390,352 |  | 1,390,352 |  | 1,219,639
Liabilities |  |  |  |  |
Derivative liabilities | 6,309 |  | 6,309 |  | 5,655
Total | 6,309 |  | 6,309 |  | 5,655
Recurring | Level 2 | U.S. government sponsored entities and U.S. agency securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 15,123 |  | 15,123 |  | 20,141
Recurring | Level 2 | Mortgage-backed securities - agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 1,048,803 |  | 1,048,803 |  | 847,056
Recurring | Level 2 | Mortgage-backed securities - non-agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 93,860 |  | 93,860 |  | 101,012
Recurring | Level 2 | Asset-backed student loans |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 43,258 |  | 43,258 |  | 49,973
Recurring | Level 2 | State and municipal securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 73,290 |  | 73,290 |  | 69,061
Recurring | Level 2 | Collateralized loan obligations |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 47,845 |  | 47,845 |  | 40,450
Recurring | Level 2 | Corporate securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 56,728 |  | 56,728 |  | 79,881
Recurring | Level 2 | Equity securities |  |  |  |  |
Assets |  |  |  |  |
Equity securities | 0 |  | 0 |  | 0
Recurring | Level 3 |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale | 0 |  | 0 |  | 0
Credit enhancement asset | 5,765 |  | 5,765 |  | 16,804
Derivative assets | 0 |  | 0 |  | 0
Total | 5,765 |  | 5,765 |  | 16,804
Liabilities |  |  |  |  |
Derivative liabilities | 0 |  | 0 |  | 0
Total | 0 |  | 0 |  | 0
Recurring | Level 3 | U.S. government sponsored entities and U.S. agency securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | Mortgage-backed securities - agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | Mortgage-backed securities - non-agency |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | Asset-backed student loans |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | State and municipal securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | Collateralized loan obligations |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | Corporate securities |  |  |  |  |
Assets |  |  |  |  |
Investment securities available for sale | 0 |  | 0 |  | 0
Recurring | Level 3 | Equity securities |  |  |  |  |
Assets |  |  |  |  |
Equity securities | 0 |  | 0 |  | 0
Non recurring |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale |  |  |  |  | 336,719
Assets measured at fair value on a non-recurring basis: |  |  |  |  |
Nonperforming loans | 44,368 |  | 44,368 |  | 120,222
Other real estate owned | 393 |  | 393 |  | 4,941
Losses recognized on assets measured on non-recurring basis |  |  |  |  |
Nonperforming loans | 5,821 | $ 355 | 16,114 | $ 14,225 |
Other real estate owned | 0 | 548 | 0 | 1,278 |
Total losses on assets measured on a nonrecurring basis | 5,821 | $ 903 | 16,114 | $ 15,503 |
Non recurring | Level 1 |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale |  |  |  |  | 0
Assets measured at fair value on a non-recurring basis: |  |  |  |  |
Nonperforming loans | 0 |  | 0 |  | 0
Other real estate owned | 0 |  | 0 |  | 0
Non recurring | Level 2 |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale |  |  |  |  | 0
Assets measured at fair value on a non-recurring basis: |  |  |  |  |
Nonperforming loans | 0 |  | 0 |  | 0
Other real estate owned | 0 |  | 0 |  | 0
Non recurring | Level 3 |  |  |  |  |
Assets |  |  |  |  |
Loans held for sale |  |  |  |  | 336,719
Assets measured at fair value on a non-recurring basis: |  |  |  |  |
Nonperforming loans | 44,368 |  | 44,368 |  | 120,222
Other real estate owned | $ 393 |  | $ 393 |  | $ 4,941

X
- Definition Credit Enhancement Asset, Fair Value Disclosure + References No definition available. + Details
Name: | msbi_CreditEnhancementAssetFairValueDisclosure
Namespace Prefix: | msbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition The gains (losses) recognized on assets representing the difference between the carrying value and fair value measured on a non recurring basis. + References No definition available. + Details
Name: | msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasis
Namespace Prefix: | msbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Definition The gains (losses) recognized on assets, impaired loans representing the difference between the carrying value and fair value measured on a non recurring basis. + References No definition available. + Details
Name: | msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisImpairedLoans
Namespace Prefix: | msbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The gains (losses) recognized on assets, other real estate owned representing the difference between the carrying value and fair value measured on a non recurring basis. + References No definition available. + Details
Name: | msbi_FairValueGainsLossesRecognizedOnAssetsMeasuredOnNonRecurringBasisOtherRealEstateOwned
Namespace Prefix: | msbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Individually Evaluated for Credit Loss, Average Recorded Investment + References No definition available. + Details
Name: | msbi_FinancingReceivableIndividuallyEvaluatedForCreditLossAverageRecordedInvestment
Namespace Prefix: | msbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value of other real estate owned (OREO) for those OREO that have been measured at fair value. + References No definition available. + Details
Name: | msbi_RealEstateOwnedOtherFairValueDisclosure
Namespace Prefix: | msbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of asset recognized for present right to economic benefit. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Indicates line item in statement of financial position that includes derivative asset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 + Details
Name: | us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix: | us-gaap_
Data Type: | enum2:enumerationSetItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-7A Reference 5: http://www.xbrl.org/2003/role/exampleRef -Name Accounting Standards Codification -Section 55 -Paragraph 10 -SubTopic 10 -Topic 825 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-10 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-12 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-22 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 21 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-21 Reference 12: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-20 Reference 13: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-15 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 16: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 17: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-12 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 23: http://www.xbrl.org/2003/role/exampleRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 55 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477439/946-210-55-1 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 27: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 28: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 29: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 30: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 31: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 32: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 33: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(3)(c)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 34: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)(Footnote 7)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 35: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(3)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 36: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column A)(Footnote 3)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5 Reference 37: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 38: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5A Reference 39: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 40: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483467/210-10-45-1 + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-28 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E + Details
Name: | us-gaap_FinancialLiabilitiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-28 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_LoansHeldForSaleFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of liabilities pertaining to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Examples include, but are not limited to, short positions in securities, derivatives and commodities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_TradingLiabilitiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=msbi_NonagencyMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=msbi_StudentLoanAssetBackedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CollateralizedLoanObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=msbi_CorporateDebtAndEquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=msbi_EquitySecurityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |