Business Segment Information (Geographical Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 778,032	$ 787,955	$ 650,147
Property and Equipment, Net	90,269	99,930	100,789
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	245,909	246,679	154,707
Property and Equipment, Net	69,782	78,080	79,794
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	223,236	192,491	163,944
Property and Equipment, Net	15,130	15,296	13,695
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	165,421	174,044	152,264
Property and Equipment, Net	4,858	5,542	5,630
Asia, Excluding China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	113,953	142,644	148,056
Property and Equipment, Net	499	1,012	1,670
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 29,513	$ 32,097	$ 31,176