Retirement Plans - Components of Net Pension Expense and Periodic Benefit Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 30, 2014	Mar. 31, 2013	Mar. 30, 2014	Mar. 31, 2013
Disclosure Retirement Plans Components Of Net Pension Expense And Periodic Benefit Costs [Abstract]
Expected return on assets	$ (1,325)	$ (1,175)	$ (2,658)	$ (2,350)
Service cost	872	1,223	1,908	2,445
Interest cost	1,222	1,119	2,479	2,239
Amortization of prior service cost	1	1	2	2
Amortization of recognized losses	258	747	556	1,494
Net pension expense	$ 1,028	$ 1,915	$ 2,287	$ 3,830