SEGMENT INFORMATION - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jan. 28, 2017	Jan. 30, 2016	Jan. 28, 2017	Jan. 30, 2016
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	$ 195.6	$ 184.6	$ 596.7	$ 596.3
Income (loss) from operations	29.1	21.5	84.8	78.4
Interest income, net	(0.2)	(0.2)	(0.3)	(0.7)
Other income, net	(1.0)	(1.0)	(2.9)	(1.5)
Income before income taxes	30.3	22.7	88.0	80.6
Operating Segments
Segment Reporting Information [Line Items]
Net sales	195.6	184.6	596.7	596.3
Transfers between segments
Segment Reporting Information [Line Items]
Net sales	0.0	0.0	0.0	0.0
Automotive
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	150.4	138.5	461.6	452.8
Income (loss) from operations	36.9	28.7	111.2	99.7
Automotive \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	152.7	141.0	467.9	459.1
Automotive \| Transfers between segments
Segment Reporting Information [Line Items]
Net sales	(2.3)	(2.5)	(6.3)	(6.3)
Interface
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	29.8	34.8	94.9	104.3
Income (loss) from operations	1.3	0.5	(0.1)	2.6
Interface \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	29.8	35.2	95.6	105.4
Interface \| Transfers between segments
Segment Reporting Information [Line Items]
Net sales	0.0	(0.4)	(0.7)	(1.1)
Power Products
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	15.4	11.3	39.9	39.1
Income (loss) from operations	3.2	1.2	7.7	4.7
Power Products \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	15.4	11.4	40.0	39.6
Power Products \| Transfers between segments
Segment Reporting Information [Line Items]
Net sales	0.0	(0.1)	(0.1)	(0.5)
Other
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	0.1	0.1	0.2	0.1
Income (loss) from operations	(3.3)	(2.1)	(8.0)	(6.2)
Other \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	0.1	0.2	2.1	0.3
Other \| Transfers between segments
Segment Reporting Information [Line Items]
Net sales	0.0	(0.1)	(1.9)	(0.2)
Eliminations/Corporate
Segment Reporting Information [Line Items]
Net sales to unaffiliated customers	(0.1)	(0.1)	0.1	0.0
Income (loss) from operations	(9.0)	(6.8)	(26.0)	(22.4)
Eliminations/Corporate \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	(2.4)	(3.2)	(8.9)	(8.1)
Eliminations/Corporate \| Transfers between segments
Segment Reporting Information [Line Items]
Net sales	$ 2.3	$ 3.1	$ 9.0	$ 8.1

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
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The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
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