Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.14)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 14

-Article 5

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- Definition

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

+ References

+ Details

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

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- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 7

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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

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Property, Plant and Equipment (Details) (USD $)	12 Months Ended
Property, Plant and Equipment (Details) (USD $)	Apr. 26, 2014	Apr. 27, 2013	Apr. 28, 2012
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	$ 455,180,000	$ 441,035,000
Construction in progress, gross	31,233,000	4,496,000
Accumulated depreciation	(327,645,000)	(322,975,000)
Net property, plant and equipment	127,535,000	118,060,000
Depreciation expense	19,300,000	19,700,000	21,200,000
Buildings and Building Fixtures [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	161,490,000	171,346,000
Buildings and Building Fixtures [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	3 years
Buildings and Building Fixtures [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	40 years
Machinery and equipment [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	140,561,000	141,924,000
Machinery and equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	3 years
Machinery and equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	15 years
Information systems and software [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	64,208,000	62,005,000
Information systems and software [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	3 years
Information systems and software [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	10 years
Land [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	15,344,000	18,433,000
Land improvements [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	10,820,000	10,772,000
Land improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	3 years
Land improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	30 years
Transportation equipment [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	17,420,000	17,855,000
Transportation equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	3 years
Transportation equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	10 years
Furniture and fixtures [Member]
Property, Plant and Equipment [Abstract]
Property, plant and equipment, gross	$ 14,104,000	$ 14,204,000
Furniture and fixtures [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	3 years
Furniture and fixtures [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated Useful Lives	15 years