Goodwill and Intangible Assets - Schedule of Carrying Value of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Oct. 01, 2017
Goodwill [Roll Forward]
Balance at beginning of the period	$ 740,886	$ 717,988
Acquisition activity	85,879	7,055
Divestiture activity	(12,160)
Translation and other	(15,785)	15,843
Balance at end of the period	798,820	740,886
GSG
Goodwill [Roll Forward]
Balance at beginning of the period	361,761	357,050
Acquisition activity	27,526	0
Divestiture activity	0
Translation and other	454	4,711
Balance at end of the period	389,741	361,761
CIG
Goodwill [Roll Forward]
Balance at beginning of the period	379,125	360,938
Acquisition activity	58,353	7,055
Divestiture activity	(12,160)
Translation and other	(16,239)	11,132
Balance at end of the period	$ 409,079	$ 379,125