Quarterly report pursuant to Section 13 or 15(d)

LOANS (Details Of Loans) (Detail)

v2.4.1.9
LOANS (Details Of Loans) (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
Accounts Notes and Loans Receivable [Line Items]        
Total Loans $ 3,607,852us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome $ 3,359,858us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome [1]    
Less allowance for loan losses (37,356)us-gaap_LoansAndLeasesReceivableAllowance (35,629)us-gaap_LoansAndLeasesReceivableAllowance [1] (31,728)us-gaap_LoansAndLeasesReceivableAllowance (30,663)us-gaap_LoansAndLeasesReceivableAllowance
Net Loans 3,570,496us-gaap_LoansAndLeasesReceivableNetReportedAmount 3,324,229us-gaap_LoansAndLeasesReceivableNetReportedAmount [1]    
Total Loans 100.00%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage 100.00%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage    
Commercial Financial and Agricultural Financing Receivable [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 1,543,531us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
1,495,092us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
   
Less allowance for loan losses (16,857)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
(16,079)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
(13,505)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
(13,576)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Total Loans 42.78%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
44.50%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
   
Commercial Real Estate Construction Financing Receivable [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 219,005us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
208,769us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
   
Less allowance for loan losses (5,889)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
(6,395)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
(6,341)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
(6,078)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Total Loans 6.07%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
6.21%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
   
Commercial Mortgage Loans Owner Occupied [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 869,724us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
793,917us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
   
Total Loans 24.11%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
23.63%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
   
One To Four Family Mortgage Loans [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 375,770us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
333,455us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
   
Total Loans 10.42%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
9.92%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
   
Other Real Estate Mortgage Loans [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 545,668us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
471,363us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
   
Total Loans 15.12%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
14.03%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
   
Residential Real Estate Mortgage Loans [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 1,791,162us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
1,598,735us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
   
Less allowance for loan losses (13,546)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
(12,112)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
(10,837)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
(10,065)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Total Loans 49.65%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
47.58%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
   
Consumer Portfolio Segment [Member]        
Accounts Notes and Loans Receivable [Line Items]        
Total Loans 54,154us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
57,262us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
Less allowance for loan losses $ (1,064)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
$ (1,043)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
$ (1,045)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
$ (944)us-gaap_LoansAndLeasesReceivableAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Total Loans 1.50%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
1.71%sfbs_LoansAndLeasesReceivableNetOfDeferredIncomePercentage
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
   
[1] derived from audited financial statements