XML 92 R41.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value Measurements (Assets And Liabilities Recorded At Fair Value On A Nonrecurring Basis) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Residential mortgage loans held for sale $ 85us-gaap_LoansHeldForSaleFairValueDisclosure $ 527us-gaap_LoansHeldForSaleFairValueDisclosure
Collateral-dependent impaired loans 2,316smmf_ImpairedLoansFairValueDisclosure 1,552smmf_ImpairedLoansFairValueDisclosure
Foreclosed properties 24,213smmf_OtherRealEstateForeclosedAssets 26,869smmf_OtherRealEstateForeclosedAssets
Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
44smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
Commercial Real Estate Portfolio Segment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 170smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
344smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Foreclosed properties 2,346smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
3,892smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Construction And Development Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 722smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
852smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Foreclosed properties 20,198smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
20,952smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Residential Real Estate Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 1,424smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
312smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Foreclosed properties 1,669smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
2,025smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Fair Value Inputs Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Residential mortgage loans held for sale 0us-gaap_LoansHeldForSaleFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
0us-gaap_LoansHeldForSaleFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Foreclosed properties 0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
Fair Value Inputs Level 1 [Member] | Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
Fair Value Inputs Level 1 [Member] | Commercial Real Estate Portfolio Segment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Foreclosed properties 0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Fair Value Inputs Level 1 [Member] | Construction And Development Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Foreclosed properties 0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Fair Value Inputs Level 1 [Member] | Residential Real Estate Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Foreclosed properties 0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Fair Value Inputs Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Residential mortgage loans held for sale 85us-gaap_LoansHeldForSaleFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
527us-gaap_LoansHeldForSaleFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Collateral-dependent impaired loans 2,316smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
1,508smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Foreclosed properties 23,243smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
26,758smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Fair Value Inputs Level 2 [Member] | Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
Fair Value Inputs Level 2 [Member] | Commercial Real Estate Portfolio Segment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 170smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
344smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Foreclosed properties 2,346smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
3,892smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Fair Value Inputs Level 2 [Member] | Construction And Development Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 722smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
852smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Foreclosed properties 20,124smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
20,841smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Fair Value Inputs Level 2 [Member] | Residential Real Estate Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 1,424smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
312smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Foreclosed properties 773smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
2,025smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Fair Value Inputs Level 3 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Residential mortgage loans held for sale 0us-gaap_LoansHeldForSaleFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
0us-gaap_LoansHeldForSaleFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
44smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Foreclosed properties 970smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
111smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
Fair Value Inputs Level 3 [Member] | Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
44smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialLoanMember
Fair Value Inputs Level 3 [Member] | Commercial Real Estate Portfolio Segment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Foreclosed properties 0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Fair Value Inputs Level 3 [Member] | Construction And Development Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Foreclosed properties 74smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
111smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ConstructionAndDevelopmentFinancialReceivableMember
Fair Value Inputs Level 3 [Member] | Residential Real Estate Financial Receivable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral-dependent impaired loans 0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
0smmf_ImpairedLoansFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
Foreclosed properties $ 896smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember
$ 0smmf_OtherRealEstateForeclosedAssets
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= smmf_ResidentialRealEstateFinancialReceivableMember