Loans and Allowance for Loan Losses (Details 5) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($) Loan
Summary of newly restructured loans by type of modification
Number of Loans \| Loan	1
Pre-Modification Recorded Balance	$ 222
Post-Modification Recorded Balance
Interest Only
Term	222
Combination
Total Modification	222
Residential Real Estate [Member]
Summary of newly restructured loans by type of modification
Pre-Modification Recorded Balance
Post-Modification Recorded Balance
Interest Only
Term
Combination
Total Modification
Commercial [Member]
Summary of newly restructured loans by type of modification
Pre-Modification Recorded Balance
Post-Modification Recorded Balance
Interest Only
Term
Combination
Total Modification
Consumer & Other [Member]
Summary of newly restructured loans by type of modification
Number of Loans \| Loan	1
Pre-Modification Recorded Balance	$ 222
Post-Modification Recorded Balance
Interest Only
Term	222
Combination
Total Modification	$ 222

Financing receivable total modification (combination, term,interest).

No definition available.

Name:	sbfg_FinancingReceivableModification
Namespace Prefix:	sbfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing receivable modification combination.

+ References

No definition available.

+ Details

Name:	sbfg_FinancingReceivableModificationCombination
Namespace Prefix:	sbfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing receivable modification interest.

+ References

No definition available.

+ Details

Name:	sbfg_FinancingReceivableModificationInterest
Namespace Prefix:	sbfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable Modification Number of Loans.

+ References

No definition available.

+ Details

Name:	sbfg_FinancingReceivableModificationNumberOfLoans
Namespace Prefix:	sbfg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing receivable modification term.

+ References

No definition available.

+ Details

Name:	sbfg_FinancingReceivableModificationTerm
Namespace Prefix:	sbfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable Troubled Debt Restructurings.

+ References

No definition available.

+ Details

Name:	sbfg_FinancingReceivableNewlyRestructuredLoansByTypeOfModificationAbstract
Namespace Prefix:	sbfg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

+ Details

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

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

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

- Details

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

- Details

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

- Details

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