Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Oct. 01, 2011
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income	$ 17,051,000	$ 19,113,000
Other comprehensive income (loss):
Translation adjustment	(10,321,000)	(11,426,000)
Changes in unrealized gains on available-for-sale securities, net of taxes	16,000	(1,000)
Other comprehensive income (loss), net of tax	(10,305,000)	(11,427,000)
Comprehensive income (loss)	6,746,000	7,686,000
Foreign Currency Translation [Abstract]
Accumulated translation adjustments	$ 40,900,000		$ 51,200,000