Net Periodic Benefit Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 29, 2012	Jul. 01, 2011	Jun. 29, 2012	Jul. 01, 2011
Defined Benefit Plans
Defined Benefit Plan Disclosure
Service cost	$ 1,072	$ 945	$ 3,281	$ 2,713
Interest cost	1,325	1,283	4,016	3,710
Settlement gain	0	0	(161)	0
Expected return on plan assets	(1,316)	(1,251)	(3,982)	(3,622)
Amortization of prior service cost	40	38	120	113
Recognized actuarial loss	621	512	1,863	1,538
Net periodic benefit cost	1,742	1,527	5,137	4,452
Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure
Interest cost	55	62	165	186
Amortization of prior service cost	1	1	3	3
Recognized actuarial loss	21	13	63	39
Net periodic benefit cost	$ 77	$ 76	$ 231	$ 228