Segment Information and Geographic Area Information - Information about Reportable Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	May 03, 2014	Feb. 01, 2014	Oct. 26, 2013	Jul. 27, 2013	Apr. 27, 2013	Jan. 26, 2013	Oct. 27, 2012	Jul. 28, 2012	May 03, 2014 segment	Apr. 27, 2013	Apr. 28, 2012
Segment Reporting Information [Line Items]
Number of reportable segments									4
Litigation Settlement Amount									$ 20.0
Net sales									772.8	519.8	465.1
Transfers between segments									(772.8)	(519.8)	(465.1)
Net sales to unaffiliated customers	224.8	189.8	190.9	167.3	148.4	123.0	129.7	118.7	772.8	519.8	465.1
Income/(loss) from operations									73.6	39.2	11.4
Interest (income)/expense, net									0.3		(0.3)
Other (income)/expense, net									(2.6)	1.3	0.3
Income before income taxes									75.9	37.9	11.4
Depreciation and amortization									25.6	18.8	16.1
Identifiable assets	575.5				434.9				575.5	434.9	403.6
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales									0	0	0
Transfers between segments									0	0	0
Automotive
Segment Reporting Information [Line Items]
Depreciation and amortization									16.2		9.0
Identifiable assets	366.1								366.1		225.8
Automotive | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									524.3	311.0	274.7
Transfers between segments									(524.3)	(311.0)	(274.7)
Net sales to unaffiliated customers									522.1	310.1	271.6
Income/(loss) from operations									71.6	38.8	10.0
Depreciation and amortization										11.3
Identifiable assets					276.9					276.9
Automotive | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales									2.2	0.9	3.1
Transfers between segments									(2.2)	(0.9)	(3.1)
Interconnect
Segment Reporting Information [Line Items]
Depreciation and amortization									2.8		3.0
Identifiable assets	155.0								155.0		135.5
Interconnect | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									170.7	142.6	130.6
Transfers between segments									(170.7)	(142.6)	(130.6)
Net sales to unaffiliated customers									167.9	140.2	127.7
Income/(loss) from operations									23.6	19.0	18.1
Depreciation and amortization										3.0
Identifiable assets					138.0					138.0
Interconnect | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales									2.8	2.4	2.9
Transfers between segments									(2.8)	(2.4)	(2.9)
Power Products
Segment Reporting Information [Line Items]
Depreciation and amortization									4.6		2.3
Identifiable assets	32.2								32.2		36.5
Power Products | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									72.7	52.9	52.4
Transfers between segments									(72.7)	(52.9)	(52.4)
Net sales to unaffiliated customers									72.5	52.7	52.0
Income/(loss) from operations									8.3	(2.1)	1.7
Depreciation and amortization										2.4
Identifiable assets					30.8					30.8
Power Products | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales									0.2	0.2	0.4
Transfers between segments									(0.2)	(0.2)	(0.4)
All Other Segments
Segment Reporting Information [Line Items]
Depreciation and amortization									0.6		0.8
Identifiable assets	4.7								4.7		5.8
All Other Segments | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									10.4	16.7	14.0
Transfers between segments									(10.4)	(16.7)	(14.0)
Net sales to unaffiliated customers									10.2	16.6	13.9
Income/(loss) from operations									(1.7)	3.5	(0.2)
Depreciation and amortization										0.9
Identifiable assets					5.2					5.2
All Other Segments | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales									0.2	0.1	0.1
Transfers between segments									(0.2)	(0.1)	(0.1)
Corporate And Intersegment Elimination
Segment Reporting Information [Line Items]
Net sales									(5.3)	(3.4)	(6.6)
Transfers between segments									5.3	3.4	6.6
Net sales to unaffiliated customers									0.1	0.2	(0.1)
Income/(loss) from operations									(28.2)	(20.0)	(18.2)
Depreciation and amortization									1.4	1.2	1.0
Identifiable assets	17.5				(16.0)				17.5	(16.0)	0
Corporate And Intersegment Elimination | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales									(5.4)	(3.6)	(6.5)
Transfers between segments									$ 5.4	$ 3.6	$ 6.5