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Loans - Credit Quality (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
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Loans by risk rating |  |  |
Total Loans | $ 1,159,332 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome | $ 1,101,256 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome | $ 1,150,050 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Commercial |  |  |
Loans by risk rating |  |  |
Total Loans | 127,196 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 104,805 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 93,001 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Real estate - commercial |  |  |
Loans by risk rating |  |  |
Total Loans | 600,629 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 560,233 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 579,687 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember
Real estate - commercial | Owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 132,665 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 121,934 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Real estate - commercial | Owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 169,315 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 172,459 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Real estate - commercial | Non-owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 158,235 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 138,257 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Real estate - commercial | Non-owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 88,477 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 73,986 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Real estate - commercial | Retail properties |  |  |
Loans by risk rating |  |  |
Total Loans | 37,780 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 37,178 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Real estate - commercial | Farm |  |  |
Loans by risk rating |  |  |
Total Loans | 14,157 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateFarmLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember | 16,419 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateFarmLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember |
Real estate - construction |  |  |
Loans by risk rating |  |  |
Total Loans | 44,795 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | 29,351 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | 42,167 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Real estate - construction | Homebuilder |  |  |
Loans by risk rating |  |  |
Total Loans | 3,204 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateHomebuilderLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | 3,683 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateHomebuilderLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Real estate - construction | Land |  |  |
Loans by risk rating |  |  |
Total Loans | 1,658 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateLandLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | 4,645 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateLandLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Real estate - construction | Commercial speculative |  |  |
Loans by risk rating |  |  |
Total Loans | 13,431 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | 13,148 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Real estate - construction | All other |  |  |
Loans by risk rating |  |  |
Total Loans | 26,502 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember | 7,875 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember |
Real estate - residential |  |  |
Loans by risk rating |  |  |
Total Loans | 370,191 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 390,201 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 414,543 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Real estate - residential | Investor |  |  |
Loans by risk rating |  |  |
Total Loans | 137,215 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 148,293 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Real estate - residential | Owner occupied |  |  |
Loans by risk rating |  |  |
Total Loans | 116,428 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialOwnerOccupiedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 116,960 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialOwnerOccupiedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Real estate - residential | Revolving and junior liens |  |  |
Loans by risk rating |  |  |
Total Loans | 116,548 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 124,948 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember |
Consumer |  |  |
Loans by risk rating |  |  |
Total Loans | 3,504 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 2,760 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 3,101 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
All other |  |  |
Loans by risk rating |  |  |
Total Loans | 13,017 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_UnallocatedFinancingReceivablesMember | 13,906 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_UnallocatedFinancingReceivablesMember | 17,551 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_UnallocatedFinancingReceivablesMember
Pass |  |  |
Loans by risk rating |  |  |
Total Loans | 1,090,065 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 996,251 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Commercial |  |  |
Loans by risk rating |  |  |
Total Loans | 118,845 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 96,371 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - commercial | Owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 124,936 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 105,683 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - commercial | Owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 154,225 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 162,586 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - commercial | Non-owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 148,212 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 122,844 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - commercial | Non-owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 78,957 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 59,674 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - commercial | Retail properties |  |  |
Loans by risk rating |  |  |
Total Loans | 36,779 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 30,059 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - commercial | Farm |  |  |
Loans by risk rating |  |  |
Total Loans | 14,157 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateFarmLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 16,419 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateFarmLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - construction | Homebuilder |  |  |
Loans by risk rating |  |  |
Total Loans | 3,204 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateHomebuilderLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 1,745 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateHomebuilderLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - construction | Land |  |  |
Loans by risk rating |  |  |
Total Loans | 1,658 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateLandLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 4,436 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateLandLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - construction | Commercial speculative |  |  |
Loans by risk rating |  |  |
Total Loans | 9,947 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 7,674 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - construction | All other |  |  |
Loans by risk rating |  |  |
Total Loans | 25,941 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 7,109 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - residential | Investor |  |  |
Loans by risk rating |  |  |
Total Loans | 134,952 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 135,136 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - residential | Owner occupied |  |  |
Loans by risk rating |  |  |
Total Loans | 109,085 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialOwnerOccupiedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 109,261 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialOwnerOccupiedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Real estate - residential | Revolving and junior liens |  |  |
Loans by risk rating |  |  |
Total Loans | 112,647 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 120,589 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | Consumer |  |  |
Loans by risk rating |  |  |
Total Loans | 3,503 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 2,759 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Pass | All other |  |  |
Loans by risk rating |  |  |
Total Loans | 13,017 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_UnallocatedFinancingReceivablesMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember | 13,906 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_UnallocatedFinancingReceivablesMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_PassMember |
Special Mention |  |  |
Loans by risk rating |  |  |
Total Loans | 28,329 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 42,782 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Commercial |  |  |
Loans by risk rating |  |  |
Total Loans | 3,948 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 7,953 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - commercial | Owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 253 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 9,048 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - commercial | Owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 11,607 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 1,968 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - commercial | Non-owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 3,235 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 1,826 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - commercial | Non-owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 8,097 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 9,840 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - commercial | Retail properties |  |  |
Loans by risk rating |  |  |
Total Loans | 1,001 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 2,989 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - construction | Homebuilder |  |  |
Loans by risk rating |  |  |
Total Loans |  | 1,770 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateHomebuilderLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - construction | Commercial speculative |  |  |
Loans by risk rating |  |  |
Total Loans |  | 3,561 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - construction | All other |  |  |
Loans by risk rating |  |  |
Total Loans |  | 32 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - residential | Investor |  |  |
Loans by risk rating |  |  |
Total Loans |  | 3,407 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Special Mention | Real estate - residential | Revolving and junior liens |  |  |
Loans by risk rating |  |  |
Total Loans | 188 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember | 388 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SpecialMentionMember |
Substandard |  |  |
Loans by risk rating |  |  |
Total Loans | 40,938 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 62,223 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Commercial |  |  |
Loans by risk rating |  |  |
Total Loans | 4,403 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 481 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - commercial | Owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 7,476 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 7,203 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - commercial | Owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 3,483 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 7,905 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - commercial | Non-owner occupied general purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 6,788 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 13,587 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - commercial | Non-owner occupied special purpose |  |  |
Loans by risk rating |  |  |
Total Loans | 1,423 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 4,472 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - commercial | Retail properties |  |  |
Loans by risk rating |  |  |
Total Loans |  | 4,130 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_CommercialRealEstateRetailPropertiesLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstatePortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - construction | Homebuilder |  |  |
Loans by risk rating |  |  |
Total Loans |  | 168 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateHomebuilderLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - construction | Land |  |  |
Loans by risk rating |  |  |
Total Loans |  | 209 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateLandLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - construction | Commercial speculative |  |  |
Loans by risk rating |  |  |
Total Loans | 3,484 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 1,913 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateCommercialSpeculativeLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - construction | All other |  |  |
Loans by risk rating |  |  |
Total Loans | 561 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 734 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ConstructionRealEstateOtherReceivableMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateConstructionFinancingReceivableMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - residential | Investor |  |  |
Loans by risk rating |  |  |
Total Loans | 2,263 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 9,750 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialInvestorLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - residential | Owner occupied |  |  |
Loans by risk rating |  |  |
Total Loans | 7,343 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialOwnerOccupiedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 7,699 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialOwnerOccupiedLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Real estate - residential | Revolving and junior liens |  |  |
Loans by risk rating |  |  |
Total Loans | 3,713 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | 3,971 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis = osbc_ResidentialRevolvingAndJuniorLiensLoanMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |
Substandard | Consumer |  |  |
Loans by risk rating |  |  |
Total Loans | $ 1 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember | $ 1 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember / us-gaap_InternalCreditAssessmentAxis = us-gaap_SubstandardMember |

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- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 + Details
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