Goodwill Impairment Test, Access of Fair Value over Carrying Value, Percentage

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Number of Reporting Units, Step One of Goodwill Impairment Test Performed

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- Definition

Number of Reporting Units with Goodwill

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Number of Reporting Units with Goodwill, Fair Value Exceeds Carrying Value

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Intangible Assets and Goodwill - Narrative - Goodwill Impairment Test (Details) $ in Millions	3 Months Ended	12 Months Ended
	Apr. 30, 2016 USD ($) reporting_unit	Apr. 30, 2016 USD ($) reporting_unit	May 02, 2015 USD ($) reporting_unit	May 03, 2014 USD ($)	Apr. 27, 2013 USD ($)
Goodwill [Line Items]
Goodwill	$ 1.7	$ 1.7	$ 1.7	$ 13.0	$ 12.9
Goodwill impairment charge		$ 0.0	11.1
Number of reporting units where Step 1 of goodwill impairment test was performed \| reporting_unit	2	2
Minimum
Goodwill [Line Items]
Percentage by which fair value exceeded carrying value	135.00%	135.00%
Maximum
Goodwill [Line Items]
Percentage by which fair value exceeded carrying value	163.00%	163.00%
Interface
Goodwill [Line Items]
Goodwill	$ 0.7	$ 0.7	$ 0.7	12.0	11.9
Number of reporting units with goodwill \| reporting_unit	1	1
Number of reporting units where fair value exceeded carrying value \| reporting_unit			2
Goodwill impairment charge		$ 0.0	$ 11.1
Power Products
Goodwill [Line Items]
Goodwill	$ 1.0	$ 1.0	1.0	1.0	$ 1.0
Number of reporting units with goodwill \| reporting_unit	1	1
Goodwill impairment charge		$ 0.0	0.0
TouchSensor \| Interface
Goodwill [Line Items]
Goodwill impairment charge	$ 11.1		$ 11.1
Eetrex \| Power Products
Goodwill [Line Items]
Asset impairment charge				$ 1.7