Voluntary Employee Separation Progaram (Details) - Voluntary Employee Separation Program - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Apr. 30, 2017	Jan. 29, 2017	Oct. 30, 2016	Oct. 29, 2017
Voluntary Employee Separation Program
Total voluntary employee separation program's expenses, pretax	$ 8.4
Incurred voluntary employee separation program's expenses, pretax	$ 0.8	$ 6.9	$ 0.2
Forecasted
Voluntary Employee Separation Program
Incurred voluntary employee separation program's expenses, pretax				$ 0.5