XML 62 R50.htm IDEA: XBRL DOCUMENT
v3.21.2

Loans and Allowance for Credit Losses on Loans - TDR (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 USD ($) | Sep. 30, 2020 USD ($) contract | Sep. 30, 2021 USD ($) | Sep. 30, 2020 USD ($) contract
Troubled debt restructurings - modified during the period |  |  |  |
# of contracts | contract |  | 1 |  | 3
Pre-modification recorded investment | $ 0 | $ 154,000 | $ 0 | $ 410,000
Post-modification recorded investment |  | $ 153,000 |  | 404,000
TDR's defaulted |  |  |  |
Pre-modification outstanding recorded investment during the period |  |  | $ 0 | $ 0
Real estate - residential | Residential Owner Occupied Loan [Member] | Home Affordable Modification Program [Member] |  |  |  |
Troubled debt restructurings - modified during the period |  |  |  |
# of contracts | contract |  | 1 |  | 3
Pre-modification recorded investment |  | $ 154,000 |  | $ 410,000
Post-modification recorded investment |  | $ 153,000 |  | $ 404,000

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

X
- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after troubled debt restructuring, of modified financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, before troubled debt restructuring, of financing receivable to be modified. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=osbc_ResidentialOwnerOccupiedLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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