Note 9 - Marketable Securities (Details Textual) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions			1 Months Ended	12 Months Ended
	Jan. 20, 2023	Nov. 07, 2022	Oct. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Proceeds from Sale and Maturity of Marketable Securities				$ 302,504	$ 377	$ 931
Marketable Securities, Total				597,732	1,211,739
Dividend Income, Operating, Total				$ 18,002	$ 16,958	$ 4,096
Albertsons Companies, Inc [Member]
Sale of Marketable Securities (in shares)			11.5
Proceeds from Sale and Maturity of Marketable Securities			$ 301,100
Equity Securities, FV-NI, Realized Gain (Loss), Total			251,500
Equity Securities, Taxes Paid on Capital Gains			$ 57,200
Investment Owned, Balance, Shares (in shares)				28.3
Marketable Securities, Total				$ 587,700
Marketable Securities, Cash Dividend Receivable, Per Share (in dollars per share)		$ 6.85
Albertsons Companies, Inc [Member] | Subsequent Event [Member]
Dividend Income, Operating, Total	$ 194,100