Schedule of Amounts Recognized in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Oct. 02, 2015
Amount Recognized in the Consolidated Balance Sheet
Non-current liability	$ (92,520)	$ (75,019)
Amounts Recognized in Accumulated Other Comprehensive Income
Ending balance	116,346	99,724
Pension Plan
Amount Recognized in the Consolidated Balance Sheet
Non-current asset	2,395	2,172
Current liability	(1,912)	(2,463)
Non-current liability	(80,000)	(63,531)
Net amount recognized	(79,517)	(63,822)
Amounts Recognized in Accumulated Other Comprehensive Income
Net actuarial loss (gain)	112,420	96,073
Prior service cost	2,951	3,436
Ending balance	115,371	99,509
Other Postretirement Benefit Plan
Amount Recognized in the Consolidated Balance Sheet
Non-current asset	0	0
Current liability	(716)	(699)
Non-current liability	(12,520)	(11,488)
Net amount recognized	(13,236)	(12,187)
Amounts Recognized in Accumulated Other Comprehensive Income
Net actuarial loss (gain)	975	232
Prior service cost	0	(17)
Ending balance	$ 975	$ 215