Borrowing Arrangements (Narrative) (Details) (USD $)	12 Months Ended
	Sep. 30, 2011	Oct. 01, 2010	Oct. 02, 2009	Mar. 02, 2007
Principal amount of convertible subordinated notes issued				$ 200,000,000
Debt Offering Number of Tranches				2
Non convertible borrowing rate for estimating fair value	6.86%	6.86%
Convertible Notes Payable	26,089,000	24,743,000
Gains (Losses) on Extinguishment of Debt	0	(79,000)	4,590,000
Principal amount of the convertible notes	26,677,000	26,677,000
Fair value of equity component	6,061,000	6,061,000
Amortized Period, in months	6.0
Long-term debt consists of convertible notes	0	24,743,000
Termination of credit facility	50,000,000	0	0
Short-term debt	26,089,000	50,000,000
Convertible Subordinated Notes 1.25% due March 2010 [Member]
Principal amount of convertible subordinated notes issued				100,000,000
Percentage of convertible subordinated notes				1.25%
Convertible debt Premium Paid Upon Retirement		15,100,000
Extinguishment of Debt, Amount		32,600,000
Convertible Subordinated Notes 1.50% Due March 2012 [Member]
Principal amount of convertible subordinated notes issued				100,000,000
Debt instrument actual if converted value	50,300,000
Non convertible borrowing rate for estimating fair value	6.86%
Percentage of convertible subordinated notes				1.50%
Convertible debt Premium Paid Upon Retirement		12,400,000
Extinguishment of Debt, Amount		20,400,000
Conversion price of the 1.50% Notes per $1000 of principal amount	$ 105.0696
Conversion price	$ 9.52
Principal amount of the convertible notes			77,300,000
Fair value of equity component			22,700,000
Stock price to calculate if converted value	$ 17.96
If-converted value of the remaining Notes exceeds the related principal amount by	$ 23,600,000
Number of shares underlying the remaining 1.50% Notes	2,800,000	2,802,206