COMMITMENTS - General Information (Details) $ in Millions	12 Months Ended
	Jan. 31, 2017 USD ($) item	Jan. 31, 2016 USD ($)	Jan. 31, 2015 USD ($)
Commitments
The number of option terms remaining | item	1
The period of the option terms	2 years
Costs of Revenues
Commitments
Rent incurred on construction projects included in the costs of revenues	$ 13.2	$ 15.0	$ 14.4
Selling, General and Administrative Expenses
Commitments
Rent expense included in selling, general and administrative expenses of continuing operations	0.6	$ 0.3	$ 0.2
TRC
Commitments
Annual lease amount for primary offices and plant	0.3
APC
Commitments
Annual lease amount for primary offices and plant	$ 0.1