Acquisitions - Additional Information (Detail) (USD $)	9 Months Ended			9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Dec. 29, 2013	Sep. 28, 2014 Johnson City And Morristown Territory Acquisition [Member]	May 23, 2014 Johnson City And Morristown Territory Acquisition [Member]
Business Acquisition [Line Items]
Effective date of business acquisition				May 23, 2014
Cash purchase	$ 12,163,000	$ 0		$ 12,163,000
Goodwill	103,294,000	102,049,000	102,049,000	1,245,000	1,245,000
Contingent consideration liability	13,000,000			13,000,000
Goodwill recognized, expected to be deductible for tax purposes				0
Contingent consideration liability range, low				1,000,000
Contingent consideration liability range, high				$ 1,800,000