Annual report pursuant to Section 13 and 15(d)

LOANS (Analysis Of Troubled Debt Restructuring) (Detail)

v2.4.1.9
LOANS (Analysis Of Troubled Debt Restructuring) (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Financing Receivable Modifications [Line Items]    
Number of Contracts 12us-gaap_FinancingReceivableModificationsNumberOfContracts2 17us-gaap_FinancingReceivableModificationsNumberOfContracts2
Pre- Modification Outstanding Recorded Investment $ 13,272us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2 $ 14,324us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Post- Modification Outstanding Recorded Investment 13,272us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2 14,324us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Previous Twelve Months Recorded Investment 5,238us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1 7,816us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Commercial Financial and Agricultural Financing Receivable [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 9us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		5us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Pre- Modification Outstanding Recorded Investment 7,139us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		2,177us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Post- Modification Outstanding Recorded Investment 7,139us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		2,177us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Previous Twelve Months Recorded Investment 925us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,067us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Commercial Real Estate Construction Financing Receivable [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 0us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		7us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Pre- Modification Outstanding Recorded Investment 0us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,781us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Post- Modification Outstanding Recorded Investment 0us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,781us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Previous Twelve Months Recorded Investment 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,781us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Commercial Mortgage Loans Owner Occupied [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 0us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		0us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Pre- Modification Outstanding Recorded Investment 0us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		0us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Post- Modification Outstanding Recorded Investment 0us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		0us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Previous Twelve Months Recorded Investment 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		3,121us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
One To Four Family Mortgage Loans [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 1us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		4us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Pre- Modification Outstanding Recorded Investment 4,449us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		10,073us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Post- Modification Outstanding Recorded Investment 4,449us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		10,073us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Previous Twelve Months Recorded Investment 4,313us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		1,847us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Other Real Estate Mortgage Loans [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 2us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember
Pre- Modification Outstanding Recorded Investment 1,684us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember 		293us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember
Post- Modification Outstanding Recorded Investment 1,684us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember 		293us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember
Previous Twelve Months Recorded Investment 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember 		0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_OtherRealEstateMortgageLoansMember
Residential Real Estate Mortgage Loans [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 3us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		5us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Pre- Modification Outstanding Recorded Investment 6,133us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		10,366us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Post- Modification Outstanding Recorded Investment 6,133us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		10,366us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Previous Twelve Months Recorded Investment 4,313us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		4,968us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Consumer Portfolio Segment [Member]    
Financing Receivable Modifications [Line Items]    
Number of Contracts 0us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember 		0us-gaap_FinancingReceivableModificationsNumberOfContracts2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember
Pre- Modification Outstanding Recorded Investment 0us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember 		0us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember
Post- Modification Outstanding Recorded Investment 0us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember 		0us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember
Previous Twelve Months Recorded Investment $ 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember 		$ 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
/ us-gaap_FinancingReceivableTroubledDebtRestructuringAxis
= us-gaap_ConsumerPortfolioSegmentMember