Restructuring (Details) $ in Millions	3 Months Ended
	Jul. 25, 2015 USD ($) facility	Jul. 26, 2014 USD ($)
Restructuring
Number of facilities sold | facility	2
Restructuring charges
Pre-tax restructuring charges since inception of plan	$ 7.9
Restructuring charges since inception of plan, net of tax	5.0
Pre-tax restructuring (income) expense	0.2	$ (0.4)
Restructuring (income) expense, net of tax	0.1	$ (0.2)
Restructuring liability	0.5
Continuing Operations
Restructuring charges
Pre-tax restructuring charges since inception of plan	4.7
Restructuring charges since inception of plan, net of tax	2.9
Discontinued Operations.
Restructuring charges
Pre-tax restructuring charges since inception of plan	3.2
Restructuring charges since inception of plan, net of tax	$ 2.1