Business Acquisitions - Results of operations from any business acquired (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Business Combinations [Abstract]
Gross revenues	$ 42,127	$ 33,468	$ 59,048
Income before income taxes	$ 3,170	$ 6,677	$ 10,755

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Name:	us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration