GOODWILL AND INTANGIBLE ASSETS - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Oct. 29, 2016	Apr. 30, 2016
Finite-lived Intangible Assets [Roll Forward]
Gross	$ 42.2	$ 42.2
Accumulated Amortization	34.4	33.3
Net	7.8	8.9
Customer relationships and agreements
Finite-lived Intangible Assets [Roll Forward]
Gross	16.3	16.3
Accumulated Amortization	15.4	15.3
Net	$ 0.9	$ 1.0
Wtd. Avg. Remaining Amortization Periods (Years)	7 years 3 months 12 days	7 years 9 months 15 days
Trade names, patents and technology licenses
Finite-lived Intangible Assets [Roll Forward]
Gross	$ 25.8	$ 25.8
Accumulated Amortization	18.9	17.9
Net	$ 6.9	$ 7.9
Wtd. Avg. Remaining Amortization Periods (Years)	1 year 11 months 3 days	2 years 4 months 21 days
Covenants not to compete
Finite-lived Intangible Assets [Roll Forward]
Gross	$ 0.1	$ 0.1
Accumulated Amortization	0.1	0.1
Net	$ 0.0	$ 0.0
Wtd. Avg. Remaining Amortization Periods (Years)	11 months	1 year 5 months