Shareholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016	Mar. 31, 2015	Jun. 19, 2014
Class Of Stock [Line Items]
Preferred stock shares authorized	25,000
Preferred stock, par value	$ 100
Common stock, shares authorized	60,000,000	60,000,000
Common stock, par value	$ 0.20	$ 0.20	$ 0.20
Preferred stock shares outstanding	0
Approved and authorized amount under the stock repurchase program				$ 400,000,000	$ 200,000,000
Additional approved and authorized amount under the stock repurchase program				$ 200,000,000
Stock repurchased during period, shares	601,400	0
Average price paid per share of repurchased stock	$ 72.25
Aggregate value of repurchased stock	$ 43,400,000
Stock repurchased during period, shares	3,737,327
Aggregate value of repurchased stock	$ 352,000,000
Remaining value of shares to repurchase in future	$ 48,000,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock shares authorized	475,000
Preferred stock, par value	$ 1.00
Preferred stock shares outstanding	0