Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 28, 2012	Sep. 28, 2012
Allowance for doubtful accounts	$ 699	$ 956
Class A Common Stock [Member]
Common stock, par value	$ 0.001	$ 0.001
Common stock voting right per share	1	1
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	46,703,839	46,496,635
Common stock, shares outstanding	46,703,839	46,496,635
Class B Common Stock [Member]
Common stock, par value	$ 0.001	$ 0.001
Common stock voting right per share	10	10
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	55,116,153	56,598,829
Common stock, shares outstanding	55,116,153	56,598,829