Stockholders' Equity and Stock Compensation Plans (Details 3) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Oct. 03, 2010
ESPP
Stock-based compensation expense	$ 10,839,000	$ 10,582,000	$ 10,178,000
Employee Stock Purchase Plan ("ESPP")
Stockholder's Equity and Stock Compensation Plans
Shares purchased	289	246	208
Weighted-average purchase price (in dollars per share)	$ 18.35	$ 21.30	$ 22.87
Cash received from exercise of purchase rights	5,300,000	5,249,000	4,733,000
Aggregate intrinsic value	935,000	926,000	892,000
Assumptions used in the Black-Scholes option-pricing model
Expected stock price volatility (as a percent)	34.70%	38.00%	38.50%
Risk-free rate of return, annual (as a percent)	0.10%	0.30%	0.50%
Expected life (in years)	1	1	1
ESPP
Stock-based compensation expense	900,000	1,000,000	1,300,000
Unrecognized compensation cost	200,000	300,000
Accumulated amount by participants to purchase entity's common stock	$ 2,800,000