Schedule of Net Periodic Pension Cost (Detail) - Pension Plans, Defined Benefit - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,287	$ 2,871	$ 10,012	$ 8,773
Interest cost	3,838	4,412	11,293	13,052
Expected return on plan assets	(6,241)	(6,060)	(18,796)	(17,964)
Amortization of prior service cost	114	119	343	345
Amortization of actuarial (gain) loss	1,996	1,580	5,397	4,639
Net periodic cost (benefit)	$ 2,994	$ 2,922	$ 8,249	$ 8,845