Note 7 - Marketable Securities (Details Textual) - USD ($) $ in Thousands, shares in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Marketable Securities, Gain (Loss)	$ (75,491)	$ 457,127	$ (215,194)	$ 542,510
Albertsons Companies, Inc [Member]
Investment Owned, Balance, Shares (in shares)	22		22

Balance held at close of period in number of shares.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-12B(Column B))
-URI https://asc.fasb.org/extlink&oid=122147990&loc=d3e611197-123010

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant