Business Segment Information (Geographical Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 828,586	$ 892,518	$ 778,032
Property and Equipment, Net	95,110	101,083	90,269
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	288,276	306,574	245,909
Property and Equipment, Net	77,491	81,119	69,782
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	236,428	224,982	223,236
Property and Equipment, Net	12,311	13,927	15,130
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	161,622	189,227	165,421
Property and Equipment, Net	4,750	5,424	4,858
Asia, excluding China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	106,910	131,771	113,953
Property and Equipment, Net	558	613	499
Americas, excluding U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 35,350	$ 39,964	$ 29,513