Segment Information - Net Sales Activity by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 26, 2015	Jul. 27, 2014	Jul. 26, 2015	Jul. 27, 2014
Revenue from External Customer [Line Items]
Net sales	$ 125,712	$ 145,742	$ 255,800	$ 278,601
Semiconductor Products Group [Member]
Revenue from External Customer [Line Items]
Net sales	125,648	145,451	253,895	277,195
All others [Member]
Revenue from External Customer [Line Items]
Net sales	$ 64	$ 291	$ 1,905	$ 1,406

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.

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)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration