Segment Information Net Sales Activity by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Oct. 25, 2015	Jul. 26, 2015	Apr. 26, 2015	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Revenue from External Customer [Line Items]
Net sales	$ 118,609	$ 115,810	$ 125,712	$ 130,088	$ 130,394	$ 148,890	$ 145,742	$ 132,859	$ 490,219	$ 557,885	$ 594,977
Semiconductor Products Group [Member]
Revenue from External Customer [Line Items]
Net sales									485,570	555,399	577,312
All Other Segments [Member]
Revenue from External Customer [Line Items]
Net sales									$ 4,649	$ 2,486	$ 17,665