Note 2 - Ownership Interests and Advances - Schedule of Carrying Value of Ownership Interests (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Dec. 30, 2020
Equity Method Companies	$ 23,945	$ 27,821
Ownership interests	10,792		$ 0
Other Method, fair value measurement alternative	11,564	19,951
Advances to companies	775	2,626
Investments and Advances to Affiliates, Current and Noncurrent	36,284	50,398
Partnership Interest [Member]
Equity Method Companies	23,828	27,550
Ownership interests	10,792	0
Other Method, fair value measurement alternative	514	19,683
Private Equity Funds [Member]
Equity Method Companies	117	271
Other Method, fair value measurement alternative	$ 258	$ 268