Annual report pursuant to Section 13 and 15(d)

LOANS (Details Of Company's Impaired Loans) (Detail)

v2.4.1.9
LOANS (Details Of Company's Impaired Loans) (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded $ 12,648us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment $ 7,263us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Unpaid Principal Balance, with no allowance recorded 12,698us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance 7,701us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
Average Recorded Investment , with no allowance recorded 11,708us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment 6,263us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
Interest Income Recognized in Period, with no allowance recorded 619us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod 305us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
Recorded Investment, with an allowance recorded 14,077us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment 24,703us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Unpaid Principal Balance, with an allowance recorded 14,557us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance 25,622us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Related Allowance with an allowance recorded 5,094us-gaap_ImpairedFinancingReceivableRelatedAllowance 6,270us-gaap_ImpairedFinancingReceivableRelatedAllowance
Average Recorded Investment , with an allowance recorded 14,975us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment 24,387us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
Interest Income Recognized in Period, with an allowance recorded 344us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod 802us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
Recorded Investment 26,725us-gaap_ImpairedFinancingReceivableRecordedInvestment 31,966us-gaap_ImpairedFinancingReceivableRecordedInvestment
Unpaid Principal Balance 27,255us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance 33,323us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Related Allowance 5,094us-gaap_ImpairedFinancingReceivableRelatedAllowance 6,270us-gaap_ImpairedFinancingReceivableRelatedAllowance
Average Recorded Investment 26,683us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment 30,650us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Interest Income Recognized in Period 963us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod 1,107us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Commercial Financial and Agricultural Financing Receivable [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 7,059us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,210us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Unpaid Principal Balance, with no allowance recorded 7,059us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,210us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Average Recorded Investment , with no allowance recorded 7,104us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,196us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Interest Income Recognized in Period, with no allowance recorded 406us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		63us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Recorded Investment, with an allowance recorded 3,291us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		2,617us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Unpaid Principal Balance, with an allowance recorded 3,291us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		2,958us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Related Allowance with an allowance recorded 1,344us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,992us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Average Recorded Investment , with an allowance recorded 3,262us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		2,844us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Interest Income Recognized in Period, with an allowance recorded 156us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		98us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Recorded Investment 10,350us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		3,827us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Unpaid Principal Balance 10,350us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		4,168us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Related Allowance 1,344us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,992us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Average Recorded Investment 10,366us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		4,040us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Interest Income Recognized in Period 562us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		161us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Commercial Real Estate Construction Financing Receivable [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 1,527us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,967us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Unpaid Principal Balance, with no allowance recorded 1,527us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		2,405us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Average Recorded Investment , with no allowance recorded 1,493us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,363us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Interest Income Recognized in Period, with no allowance recorded 40us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		32us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Recorded Investment, with an allowance recorded 4,153us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		7,271us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Unpaid Principal Balance, with an allowance recorded 4,633us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		7,750us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Related Allowance with an allowance recorded 1,448us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,597us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Average Recorded Investment , with an allowance recorded 4,382us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		6,564us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Interest Income Recognized in Period, with an allowance recorded 19us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		200us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Recorded Investment 5,680us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		9,238us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Unpaid Principal Balance 6,160us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		10,155us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Related Allowance 1,448us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,597us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Average Recorded Investment 5,875us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		7,927us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Interest Income Recognized in Period 59us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		232us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Commercial Mortgage Loans Owner Occupied [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 1,576us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		577us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Unpaid Principal Balance, with no allowance recorded 1,576us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		577us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Average Recorded Investment , with no allowance recorded 236us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		603us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Interest Income Recognized in Period, with no allowance recorded 12us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		32us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Recorded Investment, with an allowance recorded 1,001us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,509us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Unpaid Principal Balance, with an allowance recorded 1,001us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,509us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Related Allowance with an allowance recorded 160us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		620us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Average Recorded Investment , with an allowance recorded 1,140us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,573us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Interest Income Recognized in Period, with an allowance recorded 29us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		38us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Recorded Investment 2,577us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		2,086us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Unpaid Principal Balance 2,577us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		2,086us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Related Allowance 160us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		620us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Average Recorded Investment 1,376us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		2,176us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Interest Income Recognized in Period 41us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		70us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
One To Four Family Mortgage Loans [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 542us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		1,198us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Unpaid Principal Balance, with no allowance recorded 592us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		1,198us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Average Recorded Investment , with no allowance recorded 592us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		1,200us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Interest Income Recognized in Period, with no allowance recorded 19us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		55us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Recorded Investment, with an allowance recorded 2,344us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		11,120us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Unpaid Principal Balance, with an allowance recorded 2,344us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		11,120us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Related Allowance with an allowance recorded 694us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		1,210us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Average Recorded Investment , with an allowance recorded 2,743us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		10,743us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Interest Income Recognized in Period, with an allowance recorded 56us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		342us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Recorded Investment 2,886us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		12,318us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Unpaid Principal Balance 2,936us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		12,318us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Related Allowance 694us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		1,210us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Average Recorded Investment 3,335us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		11,943us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Interest Income Recognized in Period 75us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		397us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Other Real Estate Mortgage Loans [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 1,944us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		2,311us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Unpaid Principal Balance, with no allowance recorded 1,944us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		2,311us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Average Recorded Investment , with no allowance recorded 2,283us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1,901us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Interest Income Recognized in Period, with no allowance recorded 142us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		123us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Recorded Investment, with an allowance recorded 2,622us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1,487us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Unpaid Principal Balance, with an allowance recorded 2,622us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1,586us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Related Allowance with an allowance recorded 782us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		152us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Average Recorded Investment , with an allowance recorded 2,767us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1,873us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Interest Income Recognized in Period, with an allowance recorded 84us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		96us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Recorded Investment 4,566us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		3,798us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Unpaid Principal Balance 4,566us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		3,897us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Related Allowance 782us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		152us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Average Recorded Investment 5,050us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		3,774us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Interest Income Recognized in Period 226us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		219us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Residential Real Estate Mortgage Loans [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 4,062us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		4,086us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Unpaid Principal Balance, with no allowance recorded 4,112us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		4,086us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Average Recorded Investment , with no allowance recorded 3,111us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		3,704us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Interest Income Recognized in Period, with no allowance recorded 173us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		210us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Recorded Investment, with an allowance recorded 5,967us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		14,116us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Unpaid Principal Balance, with an allowance recorded 5,967us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		14,215us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Related Allowance with an allowance recorded 1,636us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		1,982us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Average Recorded Investment , with an allowance recorded 6,650us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		14,189us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Interest Income Recognized in Period, with an allowance recorded 169us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		476us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Recorded Investment 10,029us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		18,202us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Unpaid Principal Balance 10,079us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		18,301us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Related Allowance 1,636us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		1,982us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Average Recorded Investment 9,761us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		17,893us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Interest Income Recognized in Period 342us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		686us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Consumer Portfolio Segment [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		 
Unpaid Principal Balance, with no allowance recorded 0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		 
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		 
Average Recorded Investment , with no allowance recorded 0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		 
Interest Income Recognized in Period, with no allowance recorded 0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		 
Recorded Investment, with an allowance recorded 666us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		699us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Unpaid Principal Balance, with an allowance recorded 666us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		699us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Related Allowance with an allowance recorded 666us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		699us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Average Recorded Investment , with an allowance recorded 681us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		790us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Interest Income Recognized in Period, with an allowance recorded 0us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		28us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Recorded Investment 666us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		699us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Unpaid Principal Balance 666us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		699us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Related Allowance 666us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		699us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Average Recorded Investment 681us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		790us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Interest Income Recognized in Period $ 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		$ 28us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember