Changes In Outstanding Options Granted Under Equity Incentive Plans (Detail) - $ / shares	12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding, beginning of year, Shares Subject to Option	1,077,188	1,391,906	1,363,921
Granted, Shares Subject to Option	243,680	242,200	221,200
Exercised, Shares Subject to Options	(27,413)	(492,968)	(112,790)
Forfeited/cancelled Shares Subject to Option	(89,125)	(63,950)	(80,425)
Outstanding, end of year, Shares Subject to Option	1,204,330	1,077,188	1,391,906
Exercisable, end of year, Shares Subject to Option	707,725	594,863	918,706
Outstanding, beginning of year, Weighted Average Exercise Price	$ 82.30	$ 72.11	$ 68.04
Granted, Weighted Average Exercise Price	77.28	81.60	90.16
Exercised, Weighted Average Exercise Price	58.69	51.70	48.61
Forfeited/cancelled Weighted Average Exercise Price	88.93	93.73	85.73
Outstanding, end of year, Weighted Average Exercise Price	81.33	82.30	72.11
Exercisable, end of year, Weighted Average Exercise Price	$ 80.46	$ 76.64	$ 61.03