Summary of Quarterly Results of Operations (Unaudited) - Summary of Unaudited Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	May 02, 2020	Feb. 01, 2020	Oct. 26, 2019	Jul. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	May 02, 2020	May 02, 2020	Apr. 27, 2019	Apr. 28, 2018
Segment Reporting Information [Line Items]
Net Sales	$ 210.6	$ 285.9	$ 257.2	$ 270.2	$ 266.0	$ 246.9	$ 264.0	$ 223.4		$ 1,023.9	$ 1,000.3	$ 908.3
Gross Profit	59.2	79.3	68.6	75.8	70.6	64.3	70.8	60.1		282.9	265.8	239.6
Net Income	$ 30.1	$ 41.2	$ 23.8	$ 28.3	$ 22.6	$ 30.7	$ 14.6	$ 23.7	$ 123.4	$ 123.4	$ 91.6	$ 57.2
Net Income per Basic Common Share	$ 0.80	$ 1.10	$ 0.63	$ 0.75	$ 0.61	$ 0.82	$ 0.39	$ 0.63	$ 3.28	$ 3.28	$ 2.45	$ 1.54
Net Income per Diluted Common Share	$ 0.79	$ 1.09	$ 0.63	$ 0.75	$ 0.60	$ 0.82	$ 0.39	$ 0.63	$ 3.26	$ 3.26	$ 2.43	$ 1.52
Acquisition-related Expenses					$ 0.1	$ 3.8	$ 10.9	$ 0.6
Grant Income	$ (4.4)	$ (5.5)	$ 0.0	$ 0.0	(1.4)	(1.9)	(1.4)	(1.1)
Expense for Initiatives to Reduce Overall Costs and Improve Operational Profitability	0.2	1.1	0.5	0.0	1.0	2.6	2.5	0.8
Hetronic Lawsuit
Segment Reporting Information [Line Items]
Legal Fees	2.1	1.1	1.4	0.8	0.8	0.8	1.0	0.9
RSAs | Executives and non-executive members of management | 2014 Incentive Plan
Segment Reporting Information [Line Items]
Allocated share-based compensation expense, amount recorded to true-up prior periods	$ (6.5)	$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 7.4	$ 0.0		$ 5.2	$ 7.4	$ 6.0