Stockholders' Equity and Stock Compensation Plans (Details) (USD $)	12 Months Ended				1 Months Ended	12 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Oct. 03, 2010	Sep. 30, 2012 2003 Outside Director Stock Option Plan	Mar. 31, 2006 2005 Equity Incentive Plan	Sep. 30, 2012 2005 Equity Incentive Plan	Sep. 30, 2012 Restricted Stock Program	Oct. 02, 2011 Restricted Stock Program	Oct. 03, 2010 Restricted Stock Program	Sep. 30, 2012 Employee Stock Purchase Plan ("ESPP")	Oct. 02, 2011 Employee Stock Purchase Plan ("ESPP")	Oct. 03, 2010 Employee Stock Purchase Plan ("ESPP")
Stockholder's Equity and Stock Compensation Plans
Aggregate number of shares of common stock that may be granted				400,000		6,086,216	1,251,518			2,373,290
Vesting period, minimum (in years)							P3Y
Vesting period, maximum (in years)					P4Y
Minimum percentage of market value on the grant date at which participant has option to purchase common stock				100.00%
Expiration period, maximum				P10Y	P10Y	P8Y
Percentage of vesting rights after specified period					25% on each anniversary of the grant date	25% on the first anniversary of the grant date, and the balance vests monthly thereafter
Maximum amount that an employee can contribute during a purchase right period										$ 5,000
Exercise price as percentage of fair market value on first day of purchase right period										100.00%
Exercise price as percentage of fair market value on last day of purchase right period										85.00%
Stock-based compensation and related income tax benefits
Stock-based compensation expense	10,839,000	10,582,000	10,178,000				2,200,000	1,700,000	1,200,000	900,000	1,000,000	1,300,000
Income tax benefit related to stock-based compensation	(4,288,000)	(3,804,000)	(3,590,000)
Stock-based compensation, net of tax benefit	$ 6,551,000	$ 6,778,000	$ 6,588,000