XML 46 R53.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Borrowings - Additional information (Details) (USD $) | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2015 | Dec. 31, 2014 | Jan. 31, 2008
Borrowings |  |  |
Bank owned FHLBC stock | 4,300,000 us-gaap_FederalHomeLoanBankStock | $ 4,300,000 us-gaap_FederalHomeLoanBankStock |
Total borrowings | 160,391,000 us-gaap_DebtLongtermAndShorttermCombinedAmount | 169,914,000 us-gaap_DebtLongtermAndShorttermCombinedAmount |
Securities sold under repurchase agreements |  |  |
Borrowings |  |  |
Carrying amount of securities secured | 26,500,000 us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember | 21,000,000 us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember |
Fair value of the pledged collateral | 43,400,000 us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember | 43,400,000 us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember |
Number of customers having secured balances exceeding specified percentage of stockholders equity | 0 osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember |  |
Total borrowings | 26,513,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember | 21,036,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember |
Securities sold under repurchase agreements | Minimum |  |  |
Borrowings |  |  |
Maturity | 1 day |  |
Threshold percentage of stockholders' equity | 10.00%osbc_ThresholdForDisclosurePercentageOfStockholdersEquity / us-gaap_DebtInstrumentAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember / us-gaap_RangeAxis = us-gaap_MinimumMember |  |
Securities sold under repurchase agreements | Maximum |  |  |
Borrowings |  |  |
Maturity | 90 days |  |
FHLBC advances |  |  |
Borrowings |  |  |
Borrowings at FHLBC as percentage of total assets | 35.00%osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |  |
Borrowings at FHLBC as percentage of book value of certain mortgage loans | 60.00%osbc_FederalHomeLoanBankAdvancesAsPercentageOfBookValueOfCertainMortgageLoans / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |  |
FHLBC advance amount | 30,000,000 us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember | 45,000,000 us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |
Bank owned FHLBC stock | 4,300,000 us-gaap_FederalHomeLoanBankStock / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember | 4,300,000 us-gaap_FederalHomeLoanBankStock / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |
Fair value of securities collateralized | 74,100,000 osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |  |
Principal balance of loans collateralized | 46,800,000 osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |  |
Combined collateral value | 143,400,000 us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1 / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |  |
Amount available for additional borrowings | 112,100,000 us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |  |
Total borrowings | 30,000,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember | 45,000,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_FederalHomeLoanBankAdvancesMember |
Subordinated debt |  |  |
Borrowings |  |  |
Face amount | 45,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = us-gaap_SubordinatedDebtMember |  |
Total borrowings | 45,000,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_SubordinatedDebtMember | 45,000,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_SubordinatedDebtMember |
Subordinated debt | LIBOR |  |  |
Borrowings |  |  |
Variable interest rate base | three-month LIBOR |  |
Basis points added to reference rate (as a percent) | 1.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_DebtInstrumentAxis = us-gaap_SubordinatedDebtMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  |
Notes payable and other borrowings |  |  |
Borrowings |  |  |
Total borrowings | 500,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_NotesPayableToBanksMember | 500,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_NotesPayableToBanksMember |
Bank of America credit facility |  |  |
Borrowings |  |  |
Maximum borrowing capacity | 45,500,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_DebtInstrumentAxis = osbc_CreditFacilityMember |  |
Senior debt facility |  |  |
Borrowings |  |  |
Maximum borrowing capacity |  |  | 30,500,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_DebtInstrumentAxis = osbc_SeniorDebtFacilityMember
Senior debt facility | LIBOR |  |  |
Borrowings |  |  |
Variable interest rate base | three-month LIBOR |  |
Basis points added to reference rate (as a percent) | 0.90%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_DebtInstrumentAxis = osbc_SeniorDebtFacilityMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  |
Senior debt facility | Prime rate |  |  |
Borrowings |  |  |
Variable interest rate base | prime |  |
Term debt |  |  |
Borrowings |  |  |
Maximum borrowing capacity | 500,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_DebtInstrumentAxis = osbc_TermDebtMember |  |
Total borrowings | 500,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = osbc_TermDebtMember |  |
Increase in basis points on non compliance of covenant (as a percent) | 2.00%osbc_DebtInstrumentIncreaseInInterestRateOnNonComplianceOfFinancialCovenant / us-gaap_DebtInstrumentAxis = osbc_TermDebtMember |  |
Junior subordinated debentures |  |  |
Borrowings |  |  |
Total borrowings | 58,378,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_JuniorSubordinatedDebtMember | $ 58,378,000 us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = us-gaap_JuniorSubordinatedDebtMember |

X
- Definition Represents the increase in basis points retroactive to July 30, 2009 due to the bank invoking the default rate on the debt instrument. + References No definition available. + Details
Name: | osbc_DebtInstrumentIncreaseInInterestRateOnNonComplianceOfFinancialCovenant
Namespace Prefix: | osbc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the maturity term of the debt instrument. + References No definition available. + Details
Name: | osbc_DebtInstrumentMaturityTerm
Namespace Prefix: | osbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the amount of borrowings from Federal Home Loan Bank as a percentage of book value of certain mortgage loans. + References No definition available. + Details
Name: | osbc_FederalHomeLoanBankAdvancesAsPercentageOfBookValueOfCertainMortgageLoans
Namespace Prefix: | osbc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the amount of borrowings from Federal Home Loan Bank as a percentage of total assets. + References No definition available. + Details
Name: | osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets
Namespace Prefix: | osbc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the principal balance of loans pledged as collateral in support of federal home loan bank advances outstanding. + References No definition available. + Details
Name: | osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations
Namespace Prefix: | osbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the fair value of securities pledged as collateral in support of federal home loan bank advances outstanding + References No definition available. + Details
Name: | osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue
Namespace Prefix: | osbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the number of customers having secured balances exceeding specified percentage of stockholders equity. + References No definition available. + Details
Name: | osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity
Namespace Prefix: | osbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the threshold percentage which the entity uses for disclosure about the customer holding secured balances. + References No definition available. + Details
Name: | osbc_ThresholdForDisclosurePercentageOfStockholdersEquity
Namespace Prefix: | osbc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Subparagraph b -Article 5 + Details
Name: | us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the aggregate of total long-term debt, including current maturities and short-term debt. + References No definition available. + Details
Name: | us-gaap_DebtLongtermAndShorttermCombinedAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of advances from the Federal Home Loan Bank (FHLB). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the collateral pledged in support of federal home loan bank advances outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 325 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6478792&loc=d3e63345-112809 + Details
Name: | us-gaap_FederalHomeLoanBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The fair value, as of the date of each statement of financial position presented, of securities which are owned but transferred to serve as collateral for the payment of repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728 + Details
Name: | us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for repurchase agreements, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=34720971&loc=SL6224234-111729 + Details
Name: | us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=osbc_CreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=osbc_SeniorDebtFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=osbc_TermDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_FederalHomeLoanBankAdvancesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_NotesPayableToBanksMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_SubordinatedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |