Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 30, 2012	Sep. 30, 2011
Allowance for doubtful accounts	$ 2,098	$ 2,466
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	50,284,419	51,860,546
Common stock, shares outstanding	50,284,419	51,860,546
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	57,183,964	57,559,554
Common stock, shares outstanding	57,183,964	57,559,554