Intangible Assets - Summary of Activity in Intangible Assets and Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 29, 2017	Sep. 29, 2017	Sep. 30, 2016
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		$ 384,471	$ 318,006
Acquired		436,181	65,350
Placed in service		0
Fair value adjustment		0	1,678
Currency translation adjustments		(4,597)	8,857
Impairments of intangible assets		(4,352)	(10,088)
Other intangibles purchased			668
Ending balance	$ 811,703	811,703	384,471
In-process research and development
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		8,000	8,000
Acquired		0	0
Placed in service		(3,648)
Fair value adjustment		0	0
Currency translation adjustments		0	0
Impairments of intangible assets	(4,352)		0
Other intangibles purchased			0
Ending balance	0	0	8,000
Trade name
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		3,400	3,400
Acquired		0	0
Placed in service		0
Fair value adjustment		0	0
Currency translation adjustments		0	0
Impairments of intangible assets		0	0
Other intangibles purchased			0
Ending balance	3,400	3,400	3,400
Goodwill
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		120,024	93,346
Acquired		195,145	20,412
Placed in service		0
Fair value adjustment		220	3,475
Currency translation adjustments		(1,624)	2,791
Impairments of intangible assets		0	0
Other intangibles purchased			0
Ending balance	313,765	313,765	120,024
Acquired technology
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		165,397	162,536
Acquired		83,518	10,400
Placed in service	3,648
Fair value adjustment		0	78
Currency translation adjustments		(908)	1,803
Impairments of intangible assets		0	(10,088)
Other intangibles purchased			668
Ending balance	251,655	251,655	165,397
Customer relationships
Goodwill and Intangible Assets [Roll Forward]
Beginning balance		207,674	144,070
Acquired		352,663	54,950
Placed in service		0
Fair value adjustment		0	1,600
Currency translation adjustments		(3,689)	7,054
Impairments of intangible assets		0	0
Other intangibles purchased			0
Ending balance	$ 556,648	$ 556,648	$ 207,674