INTANGIBLE ASSETS AND GOODWILL - GOODWILL (Details) - USD ($)	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Goodwill activity
Goodwill, gross at the beginning of the period	$ 1,455,164,000	$ 1,331,683,000	$ 1,274,041,000
Accumulated impairment losses	(66,865,000)	(66,865,000)	(66,865,000)
Goodwill, net at the beginning of the period	1,264,818,000	1,207,176,000
Business combinations, including prior year adjustments	81,180,000	91,209,000
Foreign currency translation and other	42,301,000	(33,567,000)
Goodwill, net, at the end of the period	1,388,299,000	1,264,818,000	1,207,176,000
Goodwill Impairments
Impairments of goodwill	0	0	0
Customer Engagement
Goodwill activity
Goodwill, gross at the beginning of the period	1,307,136,000	1,188,022,000	1,131,249,000
Accumulated impairment losses	(56,043,000)	(56,043,000)	(56,043,000)
Goodwill, net at the beginning of the period	1,131,979,000	1,075,206,000
Business combinations, including prior year adjustments	77,345,000	91,209,000
Foreign currency translation and other	41,769,000	(34,436,000)
Goodwill, net, at the end of the period	1,251,093,000	1,131,979,000	1,075,206,000
Cyber Intelligence
Goodwill activity
Goodwill, gross at the beginning of the period	148,028,000	143,661,000	142,792,000
Accumulated impairment losses	(10,822,000)	(10,822,000)	(10,822,000)
Goodwill, net at the beginning of the period	132,839,000	131,970,000
Business combinations, including prior year adjustments	3,835,000	0
Foreign currency translation and other	532,000	869,000
Goodwill, net, at the end of the period	$ 137,206,000	$ 132,839,000	$ 131,970,000