BUSINESS COMBINATIONS BUSINESS COMBINATIONS - YEAR ENDED JANUARY 31, 2018 - INTANGIBLE ASSETS USEFUL LIVES (Details)
3 Months Ended 12 Months Ended
Apr. 30, 2018
Jan. 31, 2018
Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life   6 years 4 months
Minimum | Customer Relationships | Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life   2 years
Minimum | Developed Technology | Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life   3 years
Minimum | Trademarks and Trade Names | Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life   1 year
Maximum    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life 10 years  
Maximum | Customer Relationships | Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life   10 years
Maximum | Developed Technology | Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life   5 years
Maximum | Trademarks and Trade Names | Individually Insignificant Business Combinations - Year Ended January 31, 2018    
Business Acquisition [Line Items]    
Finite-Lived Intangible Asset, Useful Life   7 years