Distribution Agreements, Net - Other Identifiable Intangible Assets Net (Detail) - Distribution Agreements [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 30, 2018	Apr. 01, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Distribution agreements at cost	$ 950,549	$ 950,559
Less: Accumulated amortization	(56,280)	(50,176)
Total other identifiable intangible assets, net	$ 894,269	$ 900,383	$ 907,400	$ 913,352