Revenue Recognition and Contracts With Customers - Additional information (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 30, 2017
Contract assets, net	$ 11,012
Backlog	35,884	$ 39,202
Order or Production Backlog [Member]
Backlog	$ 98,900

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Name:	us-gaap_FiniteLivedIntangibleAssetsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant