Regulatory Matters (Details Narrative) (USD $)	9 Months Ended
Sep. 30, 2014
Banking and Thrift [Abstract]
Threshold for nonperforming borrowing relationships	$ 1,000,000
Threshold for written plan to reduce risk exposure	1,000,000
Threshold to report credit weakness or loans falling outside bank policy	$ 500,000
Tier I Capital (to average assets), Minimum Required Regulatory Capital, Ratio	8.00%
Total Capital (to risk weighted assets), Minimum Required Regulatory Capital, Ratio	11.00%

Threshold for Written Plan to Reduce Risk Exposure, Loan Balance

No definition available.

Name:	smmf_ThresholdforWrittenPlantoReduceRiskExposureLoanBalance
Namespace Prefix:	smmf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Threshold to Report Credit Weakness or Loans Falling Outside Bank Policy, Loan Balance

+ References

No definition available.

+ Details

Name:	smmf_ThresholdtoReportCreditWeaknessorLoansFallingOutsideBankPolicyLoanBalance
Namespace Prefix:	smmf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Threshold to Require Criticized Asset Reports and Formal Workout Plans, Nonperforming Borrower Relationships, Aggregate Outstanding Balance

+ References

No definition available.

+ Details

Name:	smmf_ThresholdtoRequireCriticizedAssetReportsandFormalWorkoutPlansNonperformingBorrowerRelationshipsAggregateOutstandingBalance
Namespace Prefix:	smmf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Definition

The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant