BUSINESS COMBINATIONS BUSINESS COMBINATIONS - YEAR ENDED JANUARY 31, 2018 - INTANGIBLE ASSETS USEFUL LIVES (Details)	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	10 years
Weighted-average estimated useful life of all finite-lived identifiable intangible assets (in years)		7 years 9 months 17 days
Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Weighted-average estimated useful life of all finite-lived identifiable intangible assets (in years)	6 years 10 months
Minimum | Customer Relationships | Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	3 years
Minimum | Acquired Technology | Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	3 years
Minimum | Trademarks and Trade Names | Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	1 year
Maximum | Customer Relationships | Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	10 years
Maximum | Acquired Technology | Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	8 years
Maximum | Trademarks and Trade Names | Individually Insignificant Business Combinations - Year Ended January 31, 2018
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)	7 years