Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 28, 2019	Sep. 28, 2018
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 927,455	$ 876,463
Less: accumulated depreciation	(402,814)	(362,281)
Property, Plant And Equipment, Net	524,641	514,182
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	41,950	43,342
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	282,857	283,474
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	67,748	66,866
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	117,058	111,603
Computer Systems and Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	217,087	194,079
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	30,807	30,556
Equipment Leased to Other Party [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	156,047	139,201
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant And Equipment, Gross	$ 13,901	$ 7,342