Quarterly report pursuant to Section 13 or 15(d)

EMPLOYEE AND DIRECTOR BENEFITS (Summary Of Stock Option Activity) (Detail)

v2.4.1.9
EMPLOYEE AND DIRECTOR BENEFITS (Summary Of Stock Option Activity) (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares, Outstanding at beginning of year 1,622,917us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 2,328,900us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Shares, Granted 85,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross 114,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Shares, Exercised (215,500)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised (524,400)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Shares, Forfeited 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Shares, Outstanding at end of year 1,492,917us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 1,918,500us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Shares, Exercisable 383,418us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber 731,232us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Weighted Average Exercise Price, Outstanding at beginning of year $ 9.38us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 7.69us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted Average Exercise Price, Granted $ 30.77us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice $ 13.83us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Weighted Average Exercise Price, Exercised $ 6.19us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice $ 5.21us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
Weighted Average Exercise Price, Forfeited $ 0us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice $ 0us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice
Weighted Average Exercise Price, Outstanding at end of year $ 11.06us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 8.74us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Weighted Average Exercise Price, Exercisable $ 8.64us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice $ 5.33us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
Weighted Average Remaining Contractual Term (years), Outstanding at beginning 5 years 10 months 24 days 5 years 6 months
Weighted Average Remaining Contractual Term (years), Granted 9 years 10 months 24 days 9 years 10 months 24 days
Weighted Average Remaining Contractual Term (years), Exercised 3 years 1 month 6 days 2 years 9 months 18 days
Weighted Average Remaining Contractual Term (years), Forfeited 0 years 0 years
Weighted Average Remaining Contractual Term (years), Outstanding at ending 6 years 3 months 18 days 6 years 1 month 6 days
Weighted Average Remaining Contractual Term (years), Exercisable 4 years 6 months 3 years 4 months 24 days
Aggregate Intrinsic Value, Outstanding at beginning of year $ 38,256us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue $ 14,300us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Aggregate Intrinsic Value, Granted 0sfbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedIntrinsicValue 0sfbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedIntrinsicValue
Aggregate Intrinsic Value, Exercised 5,774sfbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedIntrinsicValue 4,523sfbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedIntrinsicValue
Aggregate Intrinsic Value, Forfeited 0sfbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeitedIntrinsicValue 0sfbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeitedIntrinsicValue
Aggregate Intrinsic Value, Outstanding at end of year 32,737us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue 9,777us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Aggregate Intrinsic Value, Exercisable $ 9,335us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1 $ 6,217us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1