XML 109 R94.htm IDEA: XBRL DOCUMENT
v3.22.4

Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions - Fair Value of Derivatives (Details) | 12 Months Ended
--- | ---
Dec. 31, 2022 USD ($) item | Dec. 31, 2021 USD ($) item
Two financial institutions |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Cash collateral pledged with financial institutions, dollars | $ 11,200,000 |
Number of financial institutions in which cash collateral pledged | item | 2 |
One financial institutions |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Cash collateral pledged with financial institutions, dollars |  | $ 17,200,000
Number of financial institutions in which cash collateral pledged | item |  | 1
Interest Rate Swap [Member] |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Investment securities pledged with financial institutions, dollars | $ 0 | $ 0
Number of financial institutions in which cash collateral pledged | 5,300,000 | 180,000,000
Designated as Hedging Instrument |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative assets designated as hedging instruments, fair value | $ 2,737,000 | $ 808,000
Derivative liabilities designated as hedging instruments, fair value | $ 8,610,000 | $ 4,102,000
Designated as Hedging Instrument | Interest Rate Products | OSBC Affiliates |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 4 | 2
Notional amount | $ 275,774,000 | $ 75,774,000
Derivative assets designated as hedging instruments, fair value | 2,737,000 | 808,000
Derivative liabilities designated as hedging instruments, fair value | 8,610,000 | 4,102,000
Designated as Hedging Instrument | Interest Rate Swap [Member] | Cash flow hedges of certain variable rate commercial and commercial real estate loan pools |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Notional amount | 250,000,000.0 | 50,000,000.0
Designated as Hedging Instrument | Interest Rate Swap [Member] | Cash flow hedge of junior subordinated debentures and was executed to pay fixed and receive variable rate cash flows |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Notional amount | 25,800,000 | 25,800,000
Not Designated as Hedging Instrument |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative assets designated as hedging instruments, fair value | 3,855,000 | 3,194,000
Derivative liabilities designated as hedging instruments, fair value | $ 3,655,000 | $ 2,707,000
Not Designated as Hedging Instrument | Interest Rate Products | Commercial Loan Customers |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 21 | 26
Notional amount | $ 110,647,000 | $ 165,005,000
Derivative assets designated as hedging instruments, fair value | 3,654,000 | 2,686,000
Derivative liabilities designated as hedging instruments, fair value | 3,654,000 | 2,686,000
Not Designated as Hedging Instrument | Interest Rate Swap [Member] |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Notional amount | 110,600,000 | 165,000,000.0
Not Designated as Hedging Instrument | Commitments. |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Notional amount | $ 5,300,000 | $ 34,400,000
Not Designated as Hedging Instrument | Interest Rate Lock Commitments and Forward Contracts. |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 28 | 87
Notional amount | $ 5,298,000 | $ 34,414,000
Derivative assets designated as hedging instruments, fair value | $ 76,000 | $ 508,000
Not Designated as Hedging Instrument | Other Contracts |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Derivative, number of transactions | item | 4 | 3
Notional amount | $ 43,699,000 | $ 17,173,000
Derivative assets designated as hedging instruments, fair value | 125,000 |
Derivative liabilities designated as hedging instruments, fair value | 1,000 | 21,000
Not Designated as Hedging Instrument | Forward Contracts [Member] |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Notional amount | 2,750,000 | $ 20,000,000
Interest Income |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Amount to be reclassified as an decrease to interest expense during the next twelve months | 5,200,000 |
Interest Expense |  |
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions |  |
Amount to be reclassified as an decrease to interest expense during the next twelve months | $ 563,000 |

X
- Definition Represents the number of financial institutions in which cash collateral pledged. + References No definition available. + Details
Name: | osbc_NumberOfFinancialInstitutionsInWhichCashCollateralPledged
Namespace Prefix: | osbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.1) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),2) -URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910 + Details
Name: | us-gaap_CashCollateralForBorrowedSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of all asset derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5624163-113959 + Details
Name: | us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of all liability derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5624163-113959 + Details
Name: | us-gaap_CashFlowHedgeDerivativeInstrumentLiabilitiesAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References No definition available. + Details
Name: | us-gaap_DebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of derivative instruments of a particular group held by the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959 + Details
Name: | us-gaap_DerivativeNumberOfInstrumentsHeld
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994 + Details
Name: | us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | srt_CounterpartyNameAxis=osbc_TwoFinancialInstitutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=osbc_OneFinancialInstitutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=osbc_OsbcAffiliatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=osbc_CashFlowHedgesOfCertainVariableRateCommercialAndCommercialRealEstateLoanPoolsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=osbc_CashFlowHedgeOfJuniorSubordinatedDebenturesAndWasExecutedToPayFixedAndReceiveVariableRateCashFlowsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=osbc_CommercialLoanCustomersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=osbc_DerivativeCommitmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=osbc_InterestRateLockCommitmentsAndForwardContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_OtherContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForwardContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_InterestIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_InterestExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |