Commitments and Contingencies - Summary of Company's Purchases from Manufacturing Cooperatives (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Loss Contingencies [Line Items]
Total purchases from manufacturing cooperatives	$ 70,948	$ 66,611	$ 210,342	$ 191,709
SAC [Member]
Loss Contingencies [Line Items]
Total purchases from manufacturing cooperatives	38,569	37,267	117,729	111,408
Southeastern [Member]
Loss Contingencies [Line Items]
Total purchases from manufacturing cooperatives	$ 32,379	$ 29,344	$ 92,613	$ 80,301