Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended
	Mar. 29, 2015	Mar. 30, 2014	Jan. 30, 2015	Feb. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Business Acquisition [Line Items]
Cash purchase	$ 33,389,000	$ 0
Goodwill	109,984,000	102,049,000			106,220,000
Net sales	453,253,000	388,582,000
Operating Income	16,902,000	12,116,000
Contingent consideration liability	98,505,000	0			46,850,000	0
Unfavorable fair value adjustment to contingent consideration liability	5,089,000	0
Cleveland and Cookeville, Tennessee Territory Acquisitions [Member]
Business Acquisition [Line Items]
Effective date of business acquisition	Jan. 30, 2015
Cash purchase			13,800,000
Goodwill			1,134,000
Goodwill recognized, expected to be deductible for tax purposes			100,000
Louisville, Kentucky and Evansville, Indiana [Member]
Business Acquisition [Line Items]
Effective date of business acquisition	Feb. 27, 2015
Cash purchase				19,800,000
Goodwill				2,670,000
Goodwill recognized, expected to be deductible for tax purposes				800,000
2015 Acquisitions [Member]
Business Acquisition [Line Items]
Net sales	18,100,000
Operating Income	1,800,000
Asset Purchase Agreements [Member]
Business Acquisition [Line Items]
Contingent consideration liability	98,500,000
Contingent consideration liability range, low	6,000,000
Contingent consideration liability range, high	11,000,000
Unfavorable fair value adjustment to contingent consideration liability	5,100,000
2014 Expansion Territories and January and February Expansion Territories [Member]
Business Acquisition [Line Items]
Net sales	53,300,000
Operating Income	$ 2,900,000