2.4.0.6 Html 507 424 1 false 99 0 false 11 false false R1.htm 0000 - Document - Document and Entity Information Sheet http://www.oldsecond.com/role/DocumentAndEntityInformation Document and Entity Information true false R2.htm 0010 - Statement - Consolidated Balance Sheets Sheet http://www.oldsecond.com/role/BalanceSheet Consolidated Balance Sheets false false R3.htm 0015 - Statement - Consolidated Balance Sheets (Parenthetical) Sheet http://www.oldsecond.com/role/BalanceSheetParenthetical Consolidated Balance Sheets (Parenthetical) false false R4.htm 0020 - Statement - Consolidated Statements of Operations Sheet http://www.oldsecond.com/role/StatementOfIncome Consolidated Statements of Operations false false R5.htm 0030 - Statement - Consolidated Statements of Comprehensive Income (Loss) Sheet http://www.oldsecond.com/role/StatementOfComprehensiveIncome Consolidated Statements of Comprehensive Income (Loss) false false R6.htm 0040 - Statement - Consolidated Statements of Cash Flows Sheet http://www.oldsecond.com/role/CashFlows Consolidated Statements of Cash Flows false false R7.htm 0050 - Statement - Consolidated Statements of Changes in Stockholders' Equity Sheet http://www.oldsecond.com/role/StatementOfChangesInStockholdersEquity Consolidated Statements of Changes in Stockholders' Equity false false R8.htm 0055 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) Sheet http://www.oldsecond.com/role/StatementOfChangesInStockholdersEquityParenthetical Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) false false R9.htm 1010 - Disclosure - Summary of Significant Accounting Policies Sheet http://www.oldsecond.com/role/DisclosureSummaryOfSignificantAccountingPolicies Summary of Significant Accounting Policies false false R10.htm 1020 - Disclosure - Securities Sheet http://www.oldsecond.com/role/DisclosureSecurities Securities false false R11.htm 1030 - Disclosure - Loans Sheet http://www.oldsecond.com/role/DisclosureLoans Loans false false R12.htm 1040 - Disclosure - Allowance for Loan Losses Sheet http://www.oldsecond.com/role/DisclosureAllowanceForLoanLosses Allowance for Loan Losses false false R13.htm 1050 - Disclosure - Other Real Estate Owned Sheet http://www.oldsecond.com/role/DisclosureOtherRealEstateOwned Other Real Estate Owned false false R14.htm 1060 - Disclosure - Deposits Sheet http://www.oldsecond.com/role/DisclosureDeposits Deposits false false R15.htm 1070 - Disclosure - Borrowings Sheet http://www.oldsecond.com/role/DisclosureBorrowings Borrowings false false R16.htm 1080 - Disclosure - Junior Subordinated Debentures Sheet http://www.oldsecond.com/role/DisclosureJuniorSubordinatedDebentures Junior Subordinated Debentures false false R17.htm 1090 - Disclosure - Long-Term Incentive Plan Sheet http://www.oldsecond.com/role/DisclosureLongTermIncentivePlan Long-Term Incentive Plan false false R18.htm 1100 - Disclosure - Earnings (Loss) Per Share Sheet http://www.oldsecond.com/role/DisclosureEarningsLossPerShare Earnings (Loss) Per Share false false R19.htm 1110 - Disclosure - Regulatory & Capital Matters Sheet http://www.oldsecond.com/role/DisclosureRegulatoryAndCapitalMatters Regulatory & Capital Matters false false R20.htm 1120 - Disclosure - Fair Value Option and Fair Value Measurements Sheet http://www.oldsecond.com/role/DisclosureFairValueOptionAndFairValueMeasurements Fair Value Option and Fair Value Measurements false false R21.htm 1130 - Disclosure - Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions Sheet http://www.oldsecond.com/role/DisclosureFinancialInstrumentsWithOffBalanceSheetRiskAndDerivativeTransactions Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions false false R22.htm 1140 - Disclosure - Fair Values of Financial Instruments Sheet http://www.oldsecond.com/role/DisclosureFairValuesOfFinancialInstruments Fair Values of Financial Instruments false false R23.htm 1150 - Disclosure - Preferred Stock Sheet http://www.oldsecond.com/role/DisclosurePreferredStock Preferred Stock false false R24.htm 3020 - Disclosure - Securities (Tables) Sheet http://www.oldsecond.com/role/DisclosureSecuritiesTables Securities (Tables) false false R25.htm 3030 - Disclosure - Loans (Tables) Sheet http://www.oldsecond.com/role/DisclosureLoansTables Loans (Tables) false false R26.htm 3040 - Disclosure - Allowance for Loan Losses (Tables) Sheet http://www.oldsecond.com/role/DisclosureAllowanceForLoanLossesTables Allowance for Loan Losses (Tables) false false R27.htm 3050 - Disclosure - Other Real Estate Owned (Tables) Sheet http://www.oldsecond.com/role/DisclosureOtherRealEstateOwnedTables Other Real Estate Owned (Tables) false false R28.htm 3060 - Disclosure - Deposits (Tables) Sheet http://www.oldsecond.com/role/DisclosureDepositsTables Deposits (Tables) false false R29.htm 3070 - Disclosure - Borrowings (Tables) Sheet http://www.oldsecond.com/role/DisclosureBorrowingsTables Borrowings (Tables) false false R30.htm 3090 - Disclosure - Long-Term Incentive Plan (Tables) Sheet http://www.oldsecond.com/role/DisclosureLongTermIncentivePlanTables Long-Term Incentive Plan (Tables) false false R31.htm 3100 - Disclosure - Earnings (Loss) Per Share (Tables) Sheet http://www.oldsecond.com/role/DisclosureEarningsLossPerShareTables Earnings (Loss) Per Share (Tables) false false R32.htm 3110 - Disclosure - Regulatory & Capital Matters (Tables) Sheet http://www.oldsecond.com/role/DisclosureRegulatoryAndCapitalMattersTables Regulatory & Capital Matters (Tables) false false R33.htm 3120 - Disclosure - Fair Value Option and Fair Value Measurements (Tables) Sheet http://www.oldsecond.com/role/DisclosureFairValueOptionAndFairValueMeasurementsTables Fair Value Option and Fair Value Measurements (Tables) false false R34.htm 3130 - Disclosure - Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Tables) Sheet http://www.oldsecond.com/role/DisclosureFinancialInstrumentsWithOffBalanceSheetRiskAndDerivativeTransactionsTables Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Tables) false false R35.htm 3140 - Disclosure - Fair Values of Financial Instruments (Tables) Sheet http://www.oldsecond.com/role/DisclosureFairValuesOfFinancialInstrumentsTables Fair Values of Financial Instruments (Tables) false false R36.htm 4020 - Disclosure - Securities (Details) Sheet http://www.oldsecond.com/role/DisclosureSecuritiesDetails Securities (Details) false false R37.htm 4021 - Disclosure - Securities (Details 2) Sheet http://www.oldsecond.com/role/DisclosureSecuritiesDetails2 Securities (Details 2) false false R38.htm 4022 - Disclosure - Securities (Details 3) Sheet http://www.oldsecond.com/role/DisclosureSecuritiesDetails3 Securities (Details 3) false false R39.htm 4030 - Disclosure - Loans (Details) Sheet http://www.oldsecond.com/role/DisclosureLoansDetails Loans (Details) false false R40.htm 4031 - Disclosure - Loans (Details 2) Sheet http://www.oldsecond.com/role/DisclosureLoansDetails2 Loans (Details 2) false false R41.htm 4032 - Disclosure - Loans (Details 3) Sheet http://www.oldsecond.com/role/DisclosureLoansDetails3 Loans (Details 3) false false R42.htm 4033 - Disclosure - Loans (Details 4) Sheet http://www.oldsecond.com/role/DisclosureLoansDetails4 Loans (Details 4) false false R43.htm 4034 - Disclosure - Loans (Details 5) Sheet http://www.oldsecond.com/role/DisclosureLoansDetails5 Loans (Details 5) false false R44.htm 4040 - Disclosure - Allowance for Loan Losses (Details) Sheet http://www.oldsecond.com/role/DisclosureAllowanceForLoanLossesDetails Allowance for Loan Losses (Details) false false R45.htm 4050 - Disclosure - Other Real Estate Owned (Details) Sheet http://www.oldsecond.com/role/DisclosureOtherRealEstateOwnedDetails Other Real Estate Owned (Details) false false R46.htm 4060 - Disclosure - Deposits (Details) Sheet http://www.oldsecond.com/role/DisclosureDepositsDetails Deposits (Details) false false R47.htm 4070 - Disclosure - Borrowings (Details) Sheet http://www.oldsecond.com/role/DisclosureBorrowingsDetails Borrowings (Details) false false R48.htm 4080 - Disclosure - Junior Subordinated Debentures (Details) Sheet http://www.oldsecond.com/role/DisclosureJuniorSubordinatedDebenturesDetails Junior Subordinated Debentures (Details) false false R49.htm 4081 - Disclosure - Junior Subordinated Debentures (Details 2) Sheet http://www.oldsecond.com/role/DisclosureJuniorSubordinatedDebenturesDetails2 Junior Subordinated Debentures (Details 2) false false R50.htm 4090 - Disclosure - Long-Term Incentive Plan (Details) Sheet http://www.oldsecond.com/role/DisclosureLongTermIncentivePlanDetails Long-Term Incentive Plan (Details) false false R51.htm 4100 - Disclosure - Earnings (Loss) Per Share (Details) Sheet http://www.oldsecond.com/role/DisclosureEarningsLossPerShareDetails Earnings (Loss) Per Share (Details) false false R52.htm 4110 - Disclosure - Regulatory & Capital Matters (Details) Sheet http://www.oldsecond.com/role/DisclosureRegulatoryAndCapitalMattersDetails Regulatory & Capital Matters (Details) false false R53.htm 4120 - Disclosure - Fair Value Option and Fair Value Measurements (Details) Sheet http://www.oldsecond.com/role/DisclosureFairValueOptionAndFairValueMeasurementsDetails Fair Value Option and Fair Value Measurements (Details) false false R54.htm 4121 - Disclosure - Fair Value Option and Fair Value Measurements (Details 2) Sheet http://www.oldsecond.com/role/DisclosureFairValueOptionAndFairValueMeasurementsDetails2 Fair Value Option and Fair Value Measurements (Details 2) false false R55.htm 4122 - Disclosure - Fair Value Option and Fair Value Measurements (Details 3) Sheet http://www.oldsecond.com/role/DisclosureFairValueOptionAndFairValueMeasurementsDetails3 Fair Value Option and Fair Value Measurements (Details 3) false false R56.htm 4123 - Disclosure - Fair Value Option and Fair Value Measurements (Details 4) Sheet http://www.oldsecond.com/role/DisclosureFairValueOptionAndFairValueMeasurementsDetails4 Fair Value Option and Fair Value Measurements (Details 4) false false R57.htm 4130 - Disclosure - Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Details) Sheet http://www.oldsecond.com/role/DisclosureFinancialInstrumentsWithOffBalanceSheetRiskAndDerivativeTransactionsDetails Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Details) false false R58.htm 4131 - Disclosure - Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Details 2) Sheet http://www.oldsecond.com/role/DisclosureFinancialInstrumentsWithOffBalanceSheetRiskAndDerivativeTransactionsDetails2 Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Details 2) false false R59.htm 4140 - Disclosure - Fair Values of Financial Instruments (Details) Sheet http://www.oldsecond.com/role/DisclosureFairValuesOfFinancialInstrumentsDetails Fair Values of Financial Instruments (Details) false false R60.htm 4150 - Disclosure - Preferred Stock (Details) Sheet http://www.oldsecond.com/role/DisclosurePreferredStockDetails Preferred Stock (Details) false false All Reports Book All Reports Element osbc_FairValueInputsCreditRiskRatingAndProbabilityOfDefault had a mix of decimals attribute values: 2 3. Element osbc_FairValueInputsDiscountRateBasisSpreadOnVariableRate had a mix of decimals attribute values: 2 4. Element osbc_GainOnRecaptureOfRestrictedStock had a mix of decimals attribute values: -3 0. Element us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity had a mix of decimals attribute values: -5 0. Element us-gaap_PreferredStockValue had a mix of decimals attribute values: -5 -3. Element us-gaap_RealEstateOwnedValuationAllowance had a mix of decimals attribute values: -5 -3. Element us-gaap_RealEstateOwnedValuationAllowanceProvision had a mix of decimals attribute values: -5 -3. Element us-gaap_SubordinatedDebt had a mix of decimals attribute values: -5 -3. 'Monetary' elements on report '4020 - Disclosure - Securities (Details)' had a mix of different decimal attribute values. 'Monetary' elements on report '4070 - Disclosure - Borrowings (Details)' had a mix of different decimal attribute values. 'Monetary' elements on report '4110 - Disclosure - Regulatory & Capital Matters (Details)' had a mix of different decimal attribute values. 'Monetary' elements on report '4123 - Disclosure - Fair Value Option and Fair Value Measurements (Details 4)' had a mix of different decimal attribute values. 'Monetary' elements on report '4130 - Disclosure - Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Details)' had a mix of different decimal attribute values. 'Monetary' elements on report '4150 - Disclosure - Preferred Stock (Details)' had a mix of different decimal attribute values. Process Flow-Through: 0010 - Statement - Consolidated Balance Sheets Process Flow-Through: Removing column 'Mar. 31, 2012' Process Flow-Through: Removing column 'Dec. 31, 2011' Process Flow-Through: 0015 - Statement - Consolidated Balance Sheets (Parenthetical) Process Flow-Through: Removing column 'Mar. 31, 2012' Process Flow-Through: 0020 - Statement - Consolidated Statements of Operations Process Flow-Through: Removing column 'Dec. 31, 2012' Process Flow-Through: 0030 - Statement - Consolidated Statements of Comprehensive Income (Loss) Process Flow-Through: 0040 - Statement - Consolidated Statements of Cash Flows Process Flow-Through: 0055 - Statement - Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) osbc-20130331.xml osbc-20130331.xsd osbc-20130331_cal.xml osbc-20130331_def.xml osbc-20130331_lab.xml osbc-20130331_pre.xml true true