XML 86 R63.htm IDEA: XBRL DOCUMENT v2.4.1.9
Allowance For Loan Losses (Summary Of Net Unearned Income) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance $ 11,167us-gaap_FinancingReceivableAllowanceForCreditLosses $ 12,659us-gaap_FinancingReceivableAllowanceForCreditLosses $ 12,659us-gaap_FinancingReceivableAllowanceForCreditLosses
Charge-offs 782us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs 2,862us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs 4,833us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Recoveries 192us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery 272us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery 1,091us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Provision 250us-gaap_ProvisionForLoanLeaseAndOtherLosses 1,000us-gaap_ProvisionForLoanLeaseAndOtherLosses 2,250us-gaap_ProvisionForLoanLeaseAndOtherLosses
Ending balance 10,827us-gaap_FinancingReceivableAllowanceForCreditLosses 11,069us-gaap_FinancingReceivableAllowanceForCreditLosses 11,167us-gaap_FinancingReceivableAllowanceForCreditLosses
Allowance related to: Loans individually evaluated for impairment 771us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1    
Allowance related to: Loans collectively evaluated for impairment 10,056us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment    
Total, Allowance 10,827us-gaap_FinancingReceivableAllowanceForCreditLosses 11,069us-gaap_FinancingReceivableAllowanceForCreditLosses 11,167us-gaap_FinancingReceivableAllowanceForCreditLosses
Loans individually evaluated for impairment 50,629us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment    
Loans collectively evaluated for impairment 999,867us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment    
Total, Loans 1,050,496us-gaap_LoansAndLeasesReceivableGrossCarryingAmount    
Land and Land Development [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 3,417us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Charge-offs 180us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
2,376us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
3,535us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
Recoveries 11us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
26us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
298us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
Provision 370us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Ending balance 3,618us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
  3,417us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
Allowance related to: Loans individually evaluated for impairment 176us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Allowance related to: Loans collectively evaluated for impairment 3,442us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Total, Allowance 3,618us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
  3,417us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
Loans individually evaluated for impairment 14,019us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Loans collectively evaluated for impairment 52,539us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Total, Loans 66,558us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_LandAndLandDevelopmentMember
   
Construction [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 427us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Charge-offs 0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
Recoveries 0us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
Provision (183)us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Ending balance 244us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
  427us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
Allowance related to: Loans individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Allowance related to: Loans collectively evaluated for impairment 244us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Total, Allowance 244us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
  427us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
Loans individually evaluated for impairment 0us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Loans collectively evaluated for impairment 19,094us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Total, Loans 19,094us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConstructionLoansMember
   
Commercial [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 1,204us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Charge-offs 77us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
390us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
390us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
Recoveries 2us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
6us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
34us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
Provision 9us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Ending balance 1,138us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
  1,204us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
Allowance related to: Loans individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Allowance related to: Loans collectively evaluated for impairment 1,138us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Total, Allowance 1,138us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
  1,204us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
Loans individually evaluated for impairment 381us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Loans collectively evaluated for impairment 89,547us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Total, Loans 89,928us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
   
Owner Occupied [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 927us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Charge-offs 266us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
11us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
11us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
Recoveries 3us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
7us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
40us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
Provision 571us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Ending balance 1,235us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
  927us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
Allowance related to: Loans individually evaluated for impairment 255us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Allowance related to: Loans collectively evaluated for impairment 980us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Total, Allowance 1,235us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
  927us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
Loans individually evaluated for impairment 14,721us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Loans collectively evaluated for impairment 165,548us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Total, Loans 180,269us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_OwnerOccupiedMember
   
Non-Owner Occupied [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 1,316us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Charge-offs 0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
Recoveries 2us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
3us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
318us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
Provision (25)us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Ending balance 1,293us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
  1,316us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
Allowance related to: Loans individually evaluated for impairment 21us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Allowance related to: Loans collectively evaluated for impairment 1,272us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Total, Allowance 1,293us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
  1,316us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
Loans individually evaluated for impairment 7,817us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Loans collectively evaluated for impairment 317,947us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Total, Loans 325,764us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonOwnerOccupiedMember
   
Non-Jumbo [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 1,280us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Charge-offs 160us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
9us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
435us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
Recoveries 7us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
20us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
87us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
Provision 125us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Ending balance 1,252us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
  1,280us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
Allowance related to: Loans individually evaluated for impairment 276us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Allowance related to: Loans collectively evaluated for impairment 976us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Total, Allowance 1,252us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
  1,280us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
Loans individually evaluated for impairment 6,347us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Loans collectively evaluated for impairment 213,591us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Total, Loans 219,938us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_NonJumboMember
   
Jumbo [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 2,081us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Charge-offs 0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
8us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
65us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
Recoveries 95us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
163us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
163us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
Provision (613)us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Ending balance 1,563us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
  2,081us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
Allowance related to: Loans individually evaluated for impairment 43us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Allowance related to: Loans collectively evaluated for impairment 1,520us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Total, Allowance 1,563us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
  2,081us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
Loans individually evaluated for impairment 6,556us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Loans collectively evaluated for impairment 43,936us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Total, Loans 50,492us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= smmf_JumboMember
   
Home Equity [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 187us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Charge-offs 32us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
0us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
14us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
Recoveries 1us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
2us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
4us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
Provision 103us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Ending balance 259us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
  187us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
Allowance related to: Loans individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Allowance related to: Loans collectively evaluated for impairment 259us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Total, Allowance 259us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
  187us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
Loans individually evaluated for impairment 709us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Loans collectively evaluated for impairment 68,185us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Total, Loans 68,894us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
   
Consumer [Member]      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 97us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Charge-offs 43us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
45us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
265us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
Recoveries 49us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
20us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
74us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
Provision (24)us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Ending balance 79us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
  97us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
Allowance related to: Loans individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Allowance related to: Loans collectively evaluated for impairment 79us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Total, Allowance 79us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
  97us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
Loans individually evaluated for impairment 79us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Loans collectively evaluated for impairment 18,406us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Total, Loans 18,485us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Other      
Financing Receivable, Allowance for Credit Losses [Roll Forward]      
Beginning balance 231us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
   
Charge-offs 24us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
23us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
118us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
Recoveries 22us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
25us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
73us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
Provision (83)us-gaap_ProvisionForLoanLeaseAndOtherLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
   
Ending balance 146us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
  231us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
Allowance related to: Loans individually evaluated for impairment 0us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
   
Allowance related to: Loans collectively evaluated for impairment 146us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
   
Total, Allowance 146us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
  231us-gaap_FinancingReceivableAllowanceForCreditLosses
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
Loans individually evaluated for impairment 0us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
   
Loans collectively evaluated for impairment 11,074us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember
   
Total, Loans $ 11,074us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_UnallocatedFinancingReceivablesMember