INTANGIBLE ASSETS AND GOODWILL INTANGIBLE ASSETS AND GOODWILL - AMORTIZATION AND IMPAIRMENT (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Finite-Lived Intangible Assets
Amortization of intangible assets	$ 13,500,000	$ 16,200,000	$ 41,600,000	$ 55,000,000
Impairment of goodwill			0	0
Impairment of acquired intangible assets			$ 0	$ 0