Schedule of Net Periodic Pension Cost (Detail) - Pension Plans, Defined Benefit - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Apr. 01, 2016	Mar. 31, 2017	Apr. 01, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,368	$ 2,945	$ 6,725	$ 5,902
Interest cost	3,734	4,247	7,455	8,640
Expected return on plan assets	(6,290)	(5,993)	(12,555)	(11,904)
Amortization of prior service cost	115	112	229	226
Amortization of actuarial (gain) loss	1,638	1,577	3,401	3,059
Net periodic cost (benefit)	$ 2,565	$ 2,888	$ 5,255	$ 5,923