Goodwill and Intangible Assets Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Sep. 29, 2017
Finite-Lived Intangible Assets [Line Items]
Cost	$ 391,484		$ 379,292
Accumulated Amortization	(196,279)		(189,644)
Total	195,205		189,648
Purchases of intangible assets	$ 11,198	$ 0
Intangible Assets, Explanation of Significant Additions	12
Weighted average useful life	14 years 1 month
Amortization of Intangible Assets	$ 6,500	$ 8,400
Acquired Patents And Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	311,886		299,707
Accumulated Amortization	(134,929)		(128,986)
Total	176,957		170,721
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	56,849		56,843
Accumulated Amortization	(39,035)		(38,368)
Total	17,814		18,475
Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	22,749		22,742
Accumulated Amortization	(22,315)		(22,290)
Total	$ 434		$ 452