Income Taxes (Income Tax Reconciliation, Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 27, 2021	Mar. 28, 2020	Dec. 26, 2020
Income Tax Disclosure [Abstract]
Effective income tax (benefit) rate	1.40%	0.10%
Deferred Tax Liabilities, Net	$ 91		$ 91

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=123427490&loc=d3e31931-109318

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32537-109319

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant