Goodwill and Intangible Assets - Schedule of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 25, 2021	Dec. 26, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Balance at beginning of period	$ 91,080	$ 74,458
Goodwill acquired	108,946	16,622
Balance at end of period	$ 200,026	$ 91,080