XML 61 R50.htm IDEA: XBRL DOCUMENT v3.20.2

Loans and Allowance for Credit Losses on Loans - TDR (Details)	1 Months Ended	3 Months Ended				6 Months Ended
	Mar. 31, 2019 USD ($) contract	Jun. 30, 2020 USD ($) contract	Mar. 31, 2020 USD ($)	Jun. 30, 2019 USD ($) contract	Mar. 31, 2019 USD ($) contract	Jun. 30, 2020 USD ($) contract	Jun. 30, 2019 USD ($) contract	Dec. 31, 2019 USD ($)
Troubled debt restructurings - modified during the period
# of contracts | contract	6	2			2	2
Pre-modification recorded investment		$ 256,000			$ 294,000	$ 256,000	$ 535,000
Post-modification recorded investment	$ 429,000	253,000			292,000	253,000
TDR's defaulted
Pre-modification outstanding recorded investment during the period			$ 0		$ 0
Other information
Total Past Due		25,077,000				25,077,000
Home Affordable Modification Program [Member]
Troubled debt restructurings - modified during the period
# of contracts | contract							1
Pre-modification recorded investment							$ 39,000
Post-modification recorded investment							$ 34,000
Real estate - commercial | Commercial Real Estate, Owner Occupied General Purpose Loan [Member]
Other information
Total Past Due		$ 8,206,000				$ 8,206,000
Real estate - commercial | Commercial Real Estate, Owner Occupied General Purpose Loan [Member] | Others [Member]
Troubled debt restructurings - modified during the period
# of contracts | contract							1
Pre-modification recorded investment							$ 58,000
Post-modification recorded investment							$ 57,000
Real estate - residential | Residential Owner Occupied Loan [Member] | Home Affordable Modification Program [Member]
Troubled debt restructurings - modified during the period
# of contracts | contract		2		2		2	3
Pre-modification recorded investment		$ 256,000		$ 294,000		$ 256,000	$ 399,000
Post-modification recorded investment		253,000		$ 292,000		253,000	$ 299,000
Real estate - residential | HELOC | Residential Owner Occupied Loan [Member] | Others [Member]
Troubled debt restructurings - modified during the period
# of contracts | contract							1
Pre-modification recorded investment							$ 39,000
Post-modification recorded investment							$ 39,000
Commercial
Other information
Total Past Due		2,164,000				2,164,000		$ 4,299,000
90 Days or Greater Past Due
Other information
Total Past Due		12,719,000				12,719,000
90 Days or Greater Past Due | Real estate - commercial | Commercial Real Estate, Owner Occupied General Purpose Loan [Member]
Other information
Total Past Due		6,083,000				6,083,000
90 Days or Greater Past Due | Commercial
Other information
Total Past Due		$ 2,151,000				$ 2,151,000		$ 2,103,000

X

- References

No definition available.

+ Details

Name:	osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract
Namespace Prefix:	osbc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of financing receivable past due.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=118955255&loc=SL82922355-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919253-210447

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953401-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_LoanAndLeaseReceivablesImpairedAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=osbc_HomeAffordableModificationProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=osbc_OthersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=osbc_ResidentialOwnerOccupiedLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: