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FAIR VALUE MEASUREMENT (Financial Assets And Financial Liabilities Carried At Fair Value On A Recurring Basis) (Detail) (USD $)
In Thousands, unless otherwise specified
|
Dec. 31, 2014
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Dec. 31, 2013
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
$ 298,310us-gaap_AvailableForSaleSecurities
|
$ 265,728us-gaap_AvailableForSaleSecurities
|
| Fair Value Measurements Recurring [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Total assets at fair value |
298,310us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
265,728us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | U.S. Treasury and Government Sponsored Agencies [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
51,138us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
32,274us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Mortgage-Backed Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
95,523us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
87,748us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | State and Municipal Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
135,663us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
129,831us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Corporate Debt [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
15,986us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
15,875us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Total assets at fair value |
0us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Treasury and Government Sponsored Agencies [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | State and Municipal Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
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/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Debt [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 2 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Total assets at fair value |
298,310us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
265,728us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 2 [Member] | U.S. Treasury and Government Sponsored Agencies [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
51,138us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
32,274us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 2 [Member] | Mortgage-Backed Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
95,523us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
87,748us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 2 [Member] | State and Municipal Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
135,663us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
129,831us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 2 [Member] | Corporate Debt [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
15,986us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
15,875us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 3 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Total assets at fair value |
0us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AssetsFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 3 [Member] | U.S. Treasury and Government Sponsored Agencies [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USTreasuryAndGovernmentMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
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= us-gaap_USTreasuryAndGovernmentMember
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= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 3 [Member] | Mortgage-Backed Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_MortgageBackedSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
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= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
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= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 3 [Member] | State and Municipal Securities [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
| Fair Value Measurements Recurring [Member] | Fair Value Inputs Level 3 [Member] | Corporate Debt [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Available-for-sale securities |
$ 0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|
$ 0us-gaap_AvailableForSaleSecurities
/ sfbs_FairValueAssetsAndLiabilitiesComponentsAxis
= us-gaap_CorporateDebtSecuritiesMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
|