v2.4.1.9
STOCKHOLDERS' EQUITY (Details 1) (USD $)
6 Months Ended
Nov. 30, 2015
Aug. 31, 2015
May 31, 2015
May 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise Price $ 12.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1 $ 12.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1    
Warrant [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number Outstanding 1,637,903us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_DerivativeByNatureAxis
= us-gaap_WarrantMember
     
Warrants Outstanding Weighted Average Remaining Contractual Life (years) 3 years 9 months 25 days      
Weighted Average Exercise Price $ 15.80staf_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_DerivativeByNatureAxis
= us-gaap_WarrantMember
  $ 17.60staf_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_DerivativeByNatureAxis
= us-gaap_WarrantMember
$ 19.70staf_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_DerivativeByNatureAxis
= us-gaap_WarrantMember
Number Exercisable 1,637,903staf_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercisableNumber
/ us-gaap_DerivativeByNatureAxis
= us-gaap_WarrantMember
     
Warrants Exercisable Weighted Average Exercise Price $ 15.80staf_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_DerivativeByNatureAxis
= us-gaap_WarrantMember
     
Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise Price $ 20.00us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
     
Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Exercise Price $ 10us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_RangeAxis
= us-gaap_MinimumMember