XML 60 R47.htm IDEA: XBRL DOCUMENT
v3.25.1

Loans and Allowance for Credit Losses on Loans (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | $ 43,619 | $ 44,264
Provision for (Release of) Credit Losses | 2,285 | 3,544
Charge-offs | 4,529 | 3,988
Recoveries | 176 | 293
Financing Receivable, Allowance for Credit Loss, Ending Balance | 41,551 | 44,113
Net provision expense | 2,400 |
Commercial |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 7,813 | 3,998
Provision for (Release of) Credit Losses | 3,448 | 2,326,000
Charge-offs | 3,446 | 15
Recoveries | 32 | 73
Financing Receivable, Allowance for Credit Loss, Ending Balance | 7,847 | 6,382
Leases |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 2,136 | 2,952
Provision for (Release of) Credit Losses | 148 | (33,000)
Charge-offs | 107 |
Recoveries | 14 | 40
Financing Receivable, Allowance for Credit Loss, Ending Balance | 2,191 | 2,959
Commercial real estate - Investor |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 14,528 | 17,105
Provision for (Release of) Credit Losses | 1,094 | (902,000)
Charge-offs |  | 16
Recoveries | 14 | 83
Financing Receivable, Allowance for Credit Loss, Ending Balance | 15,636 | 16,270
Commercial real estate - Owner occupied |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 10,036 | 12,280
Provision for (Release of) Credit Losses | (2,730) | 2,580,000
Charge-offs | 47 | 3,887
Recoveries | 8 | 19
Financing Receivable, Allowance for Credit Loss, Ending Balance | 7,267 | 10,992
Construction |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 3,581 | 1,038
Provision for (Release of) Credit Losses | (91) | 59,000
Charge-offs | 821 |
Financing Receivable, Allowance for Credit Loss, Ending Balance | 2,669 | 1,097
Residential real estate - Investor |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 553 | 669
Provision for (Release of) Credit Losses | 7 | (35,000)
Recoveries | 2 | 2
Financing Receivable, Allowance for Credit Loss, Ending Balance | 562 | 636
Residential real estate - Owner occupied |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 1,509 | 1,821
Provision for (Release of) Credit Losses | 301 | (169,000)
Recoveries | 30 | 8
Financing Receivable, Allowance for Credit Loss, Ending Balance | 1,840 | 1,660
Multifamily |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 1,876 | 2,728
Provision for (Release of) Credit Losses | (23) | (135,000)
Financing Receivable, Allowance for Credit Loss, Ending Balance | 1,853 | 2,593
HELOC |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 1,578 | 1,656
Provision for (Release of) Credit Losses | 88 | (165,000)
Recoveries | 12 | 17
Financing Receivable, Allowance for Credit Loss, Ending Balance | 1,678 | 1,508
Other |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 9 | 17
Provision for (Release of) Credit Losses | 43 | 18,000
Charge-offs | 108 | 70
Recoveries | 64 | 51
Financing Receivable, Allowance for Credit Loss, Ending Balance | 8 | 16
Unfunded Loan Commitment |  |
Allowance for loan losses: |  |
Financing Receivable, Allowance for Credit Loss, Beginning Balance | 1,900 |
Financing Receivable, Allowance for Credit Loss, Ending Balance | 2,000 | $ 2,700
Unfunded Loan Commitment | Other Liabilities |  |
Allowance for loan losses: |  |
ACL on unfunded commitments | $ 2,000 |

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable and net investment in lease. + References No definition available. + Details
Name: | osbc_FinancingReceivableAndNetInvestmentInLeaseAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | osbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable and net investment in lease from recovery. + References No definition available. + Details
Name: | osbc_FinancingReceivableAndNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRecovery
Namespace Prefix: | osbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable and net investment in lease from write-off. + References No definition available. + Details
Name: | osbc_FinancingReceivableAndNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix: | osbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable and net investment in lease. + References No definition available. + Details
Name: | osbc_FinancingReceivableAndNetInvestmentInLeaseExcludingAccruedInterestCreditLossExpenseReversal
Namespace Prefix: | osbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_AllowanceForLoanAndLeaseLossesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. 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 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482454/460-10-45-1 + Details
Name: | us-gaap_OffBalanceSheetCreditLossLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

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

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

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

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

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

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

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

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

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_UnfundedLoanCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |