RESEARCH AND DEVELOPMENT, NET RESEARCH AND DEVELOPMENT, NET - R&D EXPENSES AND GRANTS (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Research and Development Expense [Abstract]
Gross research and development expenses	$ 192.6	$ 174.6	$ 181.7
Grants from IIA and other government programs recorded as a reduction in gross research and development expenses	$ 2.0	$ 3.5	$ 4.0