Retirement Benefit Plans Deferred Compensation (Details) - USD ($)	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Schedule of Deferred Compensation
Company's maximum match under employee deferred compensation program	$ 4,500
Deferred compensation arrangement with individual, employer contribution	$ 700,000	$ 600,000	$ 500,000

Amount of contributions made by employer into fund established for purposes of making future disbursement to individual in accordance with deferred compensation arrangement.

No definition available.

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