Goodwill - Schedule of Reconciliation of Activity for Goodwill (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jul. 02, 2017	Jul. 03, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill, Beginning Balance	$ 144,586	$ 117,954
Goodwill, Expansion Transactions	15,076	20,528
Goodwill, Lexington Expansion Territory adjustment		(682)
Goodwill, Measurement period adjustment	765	1,956
Goodwill, Ending Balance	$ 160,427	$ 139,756