Interim Condensed Consolidated Balance Sheets (Parenthetical) $ in Thousands	Dec. 28, 2018 USD ($) vote / shares $ / shares shares	Oct. 26, 2018 $ / shares	Sep. 29, 2017 vote / shares shares
Allowance for doubtful accounts | $	$ (6,860)
Class A Common Stock [Member]
Common stock, par value (usd per share) | $ / shares	$ 0.001	$ 0.001
Common stock voting right per share (votes per share) | vote / shares	1		1
Common stock, shares authorized (shares)	500,000,000		500,000,000
Common stock, shares issued (shares)	64,270,978		63,978,752
Common stock, shares outstanding (shares)	64,270,978		63,978,752
Class B Common Stock [Member]
Common stock, par value (usd per share) | $ / shares	$ 0.001	$ 0.001
Common stock voting right per share (votes per share) | vote / shares	10		10
Common stock, shares authorized (shares)	500,000,000		500,000,000
Common stock, shares issued (shares)	38,229,820		39,261,035
Common stock, shares outstanding (shares)	38,229,820		39,261,035