BUSINESS COMBINATIONS BUSINESS COMBINATIONS - YEAR ENDED JANUARY 31, 2016 - INTANGIBLE ASSET USEFUL LIVES (Details)	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
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, 2016
Business Acquisition
Weighted-average estimated useful life of all finite-lived identifiable intangible assets (in years)			4 years 5 months
Customer Relationships | Minimum | Individually Insignificant Business Combinations - Year Ended January 31, 2016
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)			5 years
Customer Relationships | Maximum | Individually Insignificant Business Combinations - Year Ended January 31, 2016
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)			10 years
Acquired Technology | Minimum | Individually Insignificant Business Combinations - Year Ended January 31, 2016
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)			4 years
Acquired Technology | Maximum | Individually Insignificant Business Combinations - Year Ended January 31, 2016
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)			5 years
Trademarks and Trade Names | Individually Insignificant Business Combinations - Year Ended January 31, 2016
Business Acquisition
Estimated useful lives of finite-lived intangible assets (in years)			3 years