Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 29, 2019	Sep. 28, 2018
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 926,600	$ 876,463
Less: accumulated depreciation	(388,959)	(362,281)
Property, Plant And Equipment, Net	537,641	514,182
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	43,348	43,342
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	283,717	283,474
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	71,239	66,866
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	118,117	111,603
Computer Systems and Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	202,891	194,079
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	30,711	30,556
Equipment Leased to Other Party [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	148,700	139,201
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 27,877	$ 7,342