Financial Instruments Measured at Fair Value - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 28, 2015	Dec. 27, 2014
Schedule of Available-for-sale Securities [Line Items]
Variable rate demand notes maturity year	2034
Securities amortized cost, Due in one year or less	$ 1,110	$ 1,155
Due in one year or less, Estimated Fair Value	1,110	1,155
Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities amortized cost, Due in one year or less	100	200
Due in one year or less, Estimated Fair Value	$ 100	$ 200