Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 01, 2020	Jan. 26, 2019	Feb. 01, 2020	Jan. 26, 2019
Disaggregation of Revenue [Line Items]
Net Sales	$ 285.9	$ 246.9	$ 813.3	$ 734.3
Goods Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Net Sales	274.2	239.7	783.0	709.3
Goods Transferred Over Time
Disaggregation of Revenue [Line Items]
Net Sales	11.7	7.2	30.3	25.0
U.S.
Disaggregation of Revenue [Line Items]
Net Sales	160.4	127.9	452.6	368.9
Malta
Disaggregation of Revenue [Line Items]
Net Sales	41.4	33.8	111.4	109.7
China
Disaggregation of Revenue [Line Items]
Net Sales	32.4	30.1	85.2	90.6
CANADA
Disaggregation of Revenue [Line Items]
Net Sales	23.5	26.6	79.3	74.2
Other
Disaggregation of Revenue [Line Items]
Net Sales	28.2	28.5	84.8	90.9
Auto
Disaggregation of Revenue [Line Items]
Net Sales	210.3	172.9	576.6	549.8
Auto | Goods Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Net Sales	198.6	165.7	546.3	524.8
Auto | Goods Transferred Over Time
Disaggregation of Revenue [Line Items]
Net Sales	11.7	7.2	30.3	25.0
Auto | U.S.
Disaggregation of Revenue [Line Items]
Net Sales	111.0	80.7	295.2	254.7
Auto | Malta
Disaggregation of Revenue [Line Items]
Net Sales	33.7	26.7	88.4	86.8
Auto | China
Disaggregation of Revenue [Line Items]
Net Sales	22.8	20.5	59.1	63.0
Auto | CANADA
Disaggregation of Revenue [Line Items]
Net Sales	19.3	21.1	63.4	66.2
Auto | Other
Disaggregation of Revenue [Line Items]
Net Sales	23.5	23.9	70.5	79.1
Industrial
Disaggregation of Revenue [Line Items]
Net Sales	60.1	60.2	195.8	139.8
Industrial | Goods Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Net Sales	60.1	60.2	195.8	139.8
Industrial | Goods Transferred Over Time
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Industrial | U.S.
Disaggregation of Revenue [Line Items]
Net Sales	34.2	33.8	117.3	70.8
Industrial | Malta
Disaggregation of Revenue [Line Items]
Net Sales	7.7	7.0	22.8	22.7
Industrial | China
Disaggregation of Revenue [Line Items]
Net Sales	9.5	9.6	26.0	27.5
Industrial | CANADA
Disaggregation of Revenue [Line Items]
Net Sales	4.2	5.5	15.9	8.0
Industrial | Other
Disaggregation of Revenue [Line Items]
Net Sales	4.5	4.3	13.8	10.8
Interface
Disaggregation of Revenue [Line Items]
Net Sales	14.9	13.7	39.7	44.0
Interface | Goods Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Net Sales	14.9	13.7	39.7	44.0
Interface | Goods Transferred Over Time
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Interface | U.S.
Disaggregation of Revenue [Line Items]
Net Sales	14.6	13.3	38.9	42.7
Interface | Malta
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.1	0.2	0.2
Interface | China
Disaggregation of Revenue [Line Items]
Net Sales	0.1	0.0	0.1	0.1
Interface | CANADA
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Interface | Other
Disaggregation of Revenue [Line Items]
Net Sales	0.2	0.3	0.5	1.0
Medical
Disaggregation of Revenue [Line Items]
Net Sales	0.6	0.1	1.2	0.7
Medical | Goods Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Net Sales	0.6	0.1	1.2	0.7
Medical | Goods Transferred Over Time
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Medical | U.S.
Disaggregation of Revenue [Line Items]
Net Sales	0.6	0.1	1.2	0.7
Medical | Malta
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Medical | China
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Medical | CANADA
Disaggregation of Revenue [Line Items]
Net Sales	0.0	0.0	0.0	0.0
Medical | Other
Disaggregation of Revenue [Line Items]
Net Sales	$ 0.0	$ 0.0	$ 0.0	$ 0.0