Fair Value Measurements and Other-Than-Temporary Impairments - Reconciliation of All Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Disposal of auction rate securities par value		$ 3,100,000
Available for sale auction rate securities called at par value		100,000
Available for sale auction rate securities tender value		3,000,000
Available for sale auction rate securities tender value as percent of par value		95.00%
Realized gains on calls	200,000	200,000
Fair value, measurements, recurring [Member] | Level 3 [Member] | Auction rate securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Beginning balance		2,873,000
Total Net Gains Included in Other Comprehensive Income		0
Calls		(92,000)	[1]
Sold		(2,781,000)	[2]
Ending balance		$ 0

[1] Amount represents the fair market value of the securities called. Realized gains on these calls were not significant in 2013.

[2] Amount represents the fair market value of the securities sold at 95% par value. Realized gains for 2013 were $0.2 million.