Sales by Product Group - Summary of Sales by Product Group (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2017	Sep. 30, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Product category:
Net sales	$ 134,100	$ 126,876	$ 137,384	$ 112,721	$ 109,504	$ 129,807	$ 119,033	$ 100,206	$ 511,081	$ 458,550	$ 389,810
Impact-Resistant Window and Door Products [Member]
Product category:
Net sales									433,400	381,600	319,200
Non-impact Window and Door Products [Member]
Product category:
Net sales									$ 77,700	$ 77,000	$ 70,600