Interim Condensed Consolidated Balance Sheets (Parenthetical) $ in Thousands	Mar. 27, 2020 USD ($) vote $ / shares shares	Sep. 27, 2019 USD ($) vote $ / shares shares
Allowance for doubtful accounts | $	$ (11,262)	$ (9,775)
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	1	1
Common stock, shares authorized (shares)	500,000,000	500,000,000
Common stock, shares issued (shares)	64,422,131	63,911,270
Common stock, shares outstanding (shares)	64,422,131	63,911,270
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	10	10
Common stock, shares authorized (shares)	500,000,000	500,000,000
Common stock, shares issued (shares)	36,224,820	36,229,820
Common stock, shares outstanding (shares)	36,224,820	36,229,820