Retirement Plans - Schedule of Assumptions Used to Determine Net Periodic Benefit Cost (Detail) - Defined Benefit Plans	12 Months Ended
	Oct. 02, 2015	Sep. 26, 2014	Sep. 27, 2013
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	2.58%	3.11%	2.94%
Rate of compensation increase (as a percent)	2.45%	2.51%	2.37%
Expected long-term return on assets (as a percent)	3.90%	4.21%	3.82%