Quarterly report pursuant to Section 13 or 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
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded $ 12,965us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment $ 12,648us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Unpaid Principal Balance, with no allowance recorded 13,768us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance 12,698us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
Average Recorded Investment , with no allowance recorded 11,426us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment 11,708us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
Interest Income Recognized in Period, with no allowance recorded 137us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod 619us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
Recorded Investment, with an allowance recorded 32,186us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment 14,077us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Unpaid Principal Balance, with an allowance recorded 32,666us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance 14,557us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Related Allowance with an allowance recorded 5,502sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance 5,094sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
Average Recorded Investment , with an allowance recorded 32,493us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment 14,975us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
Interest Income Recognized in Period, with an allowance recorded 414us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod 344us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
Recorded Investment 45,151us-gaap_ImpairedFinancingReceivableRecordedInvestment 26,725us-gaap_ImpairedFinancingReceivableRecordedInvestment
Unpaid Principal Balance 46,434us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance 27,255us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Related Allowance 5,502us-gaap_ImpairedFinancingReceivableRelatedAllowance 5,094us-gaap_ImpairedFinancingReceivableRelatedAllowance
Average Recorded Investment 43,919us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment 26,683us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Interest Income Recognized in Period 551us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod 963us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Commercial Financial and Agricultural Financing Receivable [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 3,137us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		7,059us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Unpaid Principal Balance, with no allowance recorded 3,248us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		7,059us-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 3,127us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		7,104us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Interest Income Recognized in Period, with no allowance recorded 43us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		406us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Recorded Investment, with an allowance recorded 20,854us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		3,291us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Unpaid Principal Balance, with an allowance recorded 20,854us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		3,291us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Related Allowance with an allowance recorded 2,191sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,344sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Average Recorded Investment , with an allowance recorded 20,705us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		3,262us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Interest Income Recognized in Period, with an allowance recorded 348us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		156us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Recorded Investment 23,991us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		10,350us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Unpaid Principal Balance 24,102us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		10,350us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Related Allowance 2,191us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		1,344us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Average Recorded Investment 23,832us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		10,366us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember
Interest Income Recognized in Period 391us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialFinancialAndAgriculturalFinancingReceivableMember 		562us-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 1,615us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,527us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Unpaid Principal Balance, with no allowance recorded 1,618us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,527us-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 1,641us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,493us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Interest Income Recognized in Period, with no allowance recorded 7us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		40us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Recorded Investment, with an allowance recorded 4,365us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		4,153us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Unpaid Principal Balance, with an allowance recorded 4,845us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		4,633us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Related Allowance with an allowance recorded 1,240sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,448sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Average Recorded Investment , with an allowance recorded 4,392us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		4,382us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Interest Income Recognized in Period, with an allowance recorded 0us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		19us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Recorded Investment 5,980us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		5,680us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Unpaid Principal Balance 6,463us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		6,160us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Related Allowance 1,240us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		1,448us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Average Recorded Investment 6,033us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		5,875us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember
Interest Income Recognized in Period 7us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstateConstructionFinancingReceivableMember 		59us-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 4,731us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,576us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Unpaid Principal Balance, with no allowance recorded 4,947us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,576us-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 3,610us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		236us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Interest Income Recognized in Period, with no allowance recorded 48us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		12us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Recorded Investment, with an allowance recorded 3,028us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,001us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Unpaid Principal Balance, with an allowance recorded 3,028us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,001us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Related Allowance with an allowance recorded 237sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		160sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Average Recorded Investment , with an allowance recorded 3,040us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,140us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Interest Income Recognized in Period, with an allowance recorded 36us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		29us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Recorded Investment 7,759us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		2,577us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Unpaid Principal Balance 7,975us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		2,577us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Related Allowance 237us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		160us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Average Recorded Investment 6,650us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		1,376us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember
Interest Income Recognized in Period 84us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_CommercialMortgageLoansOwnerOccupiedMember 		41us-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 1,474us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		542us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Unpaid Principal Balance, with no allowance recorded 1,768us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		592us-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 1,059us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		592us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Interest Income Recognized in Period, with no allowance recorded 6us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		19us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Recorded Investment, with an allowance recorded 1,082us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		2,344us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Unpaid Principal Balance, with an allowance recorded 1,082us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		2,344us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Related Allowance with an allowance recorded 487sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		694sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Average Recorded Investment , with an allowance recorded 1,083us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		2,743us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Interest Income Recognized in Period, with an allowance recorded 11us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		56us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Recorded Investment 2,556us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		2,886us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Unpaid Principal Balance 2,850us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		2,936us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Related Allowance 487us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		694us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Average Recorded Investment 2,142us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		3,335us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Interest Income Recognized in Period 17us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember 		75us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OneToFourFamilyMortgageLoansMember
Other Real Estate Mortgage Loans [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 1,981us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1,944us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Unpaid Principal Balance, with no allowance recorded 2,154us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		1,944us-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 1,971us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		2,283us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Interest Income Recognized in Period, with no allowance recorded 33us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		142us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Recorded Investment, with an allowance recorded 2,193us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		2,622us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Unpaid Principal Balance, with an allowance recorded 2,193us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		2,622us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Related Allowance with an allowance recorded 683sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		782sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Average Recorded Investment , with an allowance recorded 2,609us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		2,767us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Interest Income Recognized in Period, with an allowance recorded 19us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		84us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Recorded Investment 4,174us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		4,566us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Unpaid Principal Balance 4,347us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		4,566us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Related Allowance 683us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		782us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Average Recorded Investment 4,580us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		5,050us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Interest Income Recognized in Period 52us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember 		226us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_OtherRealEstateMortgageLoansMember
Residential Real Estate Mortgage Loans [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 8,186us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		4,062us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Unpaid Principal Balance, with no allowance recorded 8,869us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		4,112us-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 6,640us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		3,111us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Interest Income Recognized in Period, with no allowance recorded 87us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		173us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Recorded Investment, with an allowance recorded 6,303us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		5,967us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Unpaid Principal Balance, with an allowance recorded 6,303us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		5,967us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Related Allowance with an allowance recorded 1,407sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		1,636sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Average Recorded Investment , with an allowance recorded 6,732us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		6,650us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Interest Income Recognized in Period, with an allowance recorded 66us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		169us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Recorded Investment 14,489us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		10,029us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Unpaid Principal Balance 15,172us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		10,079us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Related Allowance 1,407us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		1,636us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Average Recorded Investment 13,372us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		9,761us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Interest Income Recognized in Period 153us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember 		342us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= sfbs_ResidentialRealEstateMortgageLoansMember
Consumer Portfolio Segment [Member]    
Financing Receivable Impaired [Line Items]    
Recorded Investment, with no allowance recorded 27us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Unpaid Principal Balance, with no allowance recorded 33us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Related Allowance, with no allowance recorded 0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		0sfbs_ImpairedFinancingReceivableWithNoRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Average Recorded Investment , with no allowance recorded 18us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		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 		0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Recorded Investment, with an allowance recorded 664us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		666us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Unpaid Principal Balance, with an allowance recorded 664us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		666us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Related Allowance with an allowance recorded 664sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		666sfbs_ImpairedFinancingReceivableWithRelatedAllowanceRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Average Recorded Investment , with an allowance recorded 664us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		681us-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 		0us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Recorded Investment 691us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		666us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Unpaid Principal Balance 697us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		666us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Related Allowance 664us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		666us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Average Recorded Investment 682us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		681us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Interest Income Recognized in Period $ 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember 		$ 0us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember