Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	3 Months Ended
	Dec. 27, 2020 USD ($)
Goodwill
Balance at beginning of the period	$ 993,498
Translation	24,411
Balance at end of the period	1,017,909
GSG
Goodwill
Balance at beginning of the period	516,315
Translation	5,834
Balance at end of the period	522,149
CIG
Goodwill
Balance at beginning of the period	477,183
Translation	18,577
Balance at end of the period	$ 495,760