Interim Condensed Consolidated Balance Sheets (Parenthetical) $ in Thousands	Jun. 26, 2015 USD ($) $ / shares vote / shares shares	Sep. 26, 2014 USD ($) $ / shares vote / shares shares
Allowance for doubtful accounts | $	$ (1,603)	$ (1,615)
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)	51,903,757	50,658,627
Common stock, shares outstanding (shares)	51,903,757	50,658,627
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)	50,743,661	51,610,239
Common stock, shares outstanding (shares)	50,743,661	51,610,239