Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Income Statement [Abstract]
Net sales	$ 482,342	$ 464,107	$ 1,441,025	$ 1,233,013
Cost of sales	274,006	256,921	800,236	704,798
Gross profit	208,336	207,186	640,789	528,215
Operating expenses:
Research and development	34,303	30,483	100,478	88,103
Selling, general and administrative	70,291	72,383	220,874	218,602
Gain from business combination	0	0	0	(5,416)
Impairment and other charges	611	0	766	0
Amortization of intangible assets	2,607	3,743	8,163	13,060
Total operating expenses	107,812	106,609	330,281	314,349
Income from operations	100,524	100,577	310,508	213,866
Other income (expense):
Interest income	444	282	1,355	560
Interest expense	(4,737)	(7,494)	(21,209)	(24,456)
Other—net	(3,332)	(730)	(5,781)	10,871
Total other income (expense), net	(7,625)	(7,942)	(25,635)	(13,025)
Income from continuing operations before income taxes	92,899	92,635	284,873	200,841
Provision for income taxes	25,929	29,764	110,698	65,084
Net income from continuing operations	66,970	62,871	174,175	135,757
Loss from discontinued operations, net of income taxes	0	(1,754)	(2)	(2,387)
Net income	$ 66,970	$ 61,117	$ 174,173	$ 133,370
Basic net income per share:
Income per share from continuing operations (in USD per share)	$ 2.72	$ 2.56	$ 7.06	$ 5.55
Loss per share from discontinued operations, net of income taxes (in USD per share)	0.00	(0.07)	0.00	(0.10)
Net income per share (in USD per share)	2.72	2.49	7.06	5.45
Diluted net income per share:
Income per share from continuing operations (in USD per share)	2.69	2.53	6.98	5.49
Loss per share from discontinued operations, net of income taxes (in USD per share)	0.00	(0.07)	0.00	(0.10)
Net income per share (in USD per share)	$ 2.69	$ 2.46	$ 6.98	$ 5.39
Shares used in computation:
Basic (shares)	24,658	24,537	24,684	24,460
Diluted (shares)	24,877	24,823	24,971	24,741