Customer Lists and Other Identifiable Intangible Assets, Net - Reconciliation of Activity for Other Identifiable Intangible Assets (Detail) - Customer Lists and Other Identifiable Intangible Assets [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Jan. 01, 2017
Finite Lived Intangible Assets [Line Items]
Total Other Identifiable Intangible Assets, Beginning Balance		$ 10,427	$ 6,662
System Transformation Transactions acquisitions	[1]	9,200	4,600
Measurement period adjustment	[2]	150
Additional accumulated amortization		(1,457)	(835)
Total Other Identifiable Intangible Assets, Ending Balance		$ 18,320	$ 10,427

[1] System Transformation Transactions acquisitions includes an increase of $0.5 million in 2017 from the opening balance sheets for the Expansion Territories and Expansion Facilities acquired in the System Transformation during 2017, as disclosed in the financial statements in the Company’s filed periodic reports. These adjustments are for post-closing adjustments made in accordance with the applicable asset purchase agreement or asset exchange agreement for each System Transformation Transaction. The adjustments to amortization expense associated with these measurement period adjustments were not material to the consolidated financial statements.

[2] Measurement period adjustment relates to post-closing adjustments made in accordance with the terms and conditions of the September 2016 Distribution APA and the September 2016 Manufacturing APA for the October 2016 Transactions. The adjustments to amortization expense associated with this measurement period adjustment were not material to the consolidated financial statements.