Retirement Plans - Actuarial Assumptions Used to Determine Net Pension Expense and Periodic Benefit Costs (Detail)	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 25, 2012	Mar. 31, 2013	Mar. 25, 2012
Disclosure Retirement Plans Actuarial Assumptions Used To Determine Net Pension Expense And Periodic Benefit Costs [Abstract]
Discount rate	3.70%	4.50%	3.70%	4.50%
Rate of increase in compensation levels	3.00%	3.00%	3.00%	3.00%
Expected long-term rate of return on assets	6.00%	6.50%	6.00%	6.50%