XML 78 R68.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions - Commitments (Details) - USD ($) $ in Thousands | Sep. 30, 2016 | Dec. 31, 2015
--- | --- | ---
Company's contractual commitments due to letters of credit |  |
Total letters of credit | $ 13,311 | $ 11,670
Fixed |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 305 | 126
Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 13,006 | 11,544
Borrower |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 12,682 | 11,095
Borrower | Fixed |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 210 | 126
Borrower | Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 12,472 | 10,969
Borrower | Financial standby |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 3,794 | 3,632
Borrower | Financial standby | Fixed |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 127 | 60
Borrower | Financial standby | Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 3,667 | 3,572
Borrower | Commercial standby |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 126 | 47
Borrower | Commercial standby | Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 126 | 47
Borrower | Performance standby |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 8,762 | 7,416
Borrower | Performance standby | Fixed |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 83 | 66
Borrower | Performance standby | Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 8,679 | 7,350
Nonborrower |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 629 | 575
Nonborrower | Fixed |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 95 |
Nonborrower | Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 534 | 575
Nonborrower | Performance standby |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 629 | 575
Nonborrower | Performance standby | Fixed |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | 95 |
Nonborrower | Performance standby | Variable |  |
Company's contractual commitments due to letters of credit |  |
Total letters of credit | $ 534 | $ 575

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 The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_UnderlyingAssetClassAxis=osbc_FixedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnderlyingAssetClassAxis=osbc_VariableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=osbc_CommitmentsToExtendCreditToBorrowersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_FinancialStandbyLetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_PerformanceGuaranteeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=osbc_CommitmentsToExtendCreditNonborrowersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |