Cash, Cash Equivalents, and Investments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Gross realized gains on sale of investments	$ 787	$ 361	$ 3,613	$ 818
Gross realized losses on sale of investments	1	$ 67	22	$ 103
Other Current Assets
Cash and Cash Equivalents [Line Items]
Accrued interest receivable	$ 1,912		$ 1,912		$ 2,874

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

No definition available.

+ Details

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

- Definition

This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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