Note 7 - Selected Balance Sheet Data - Equity Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Investment in partnerships	$ 538	$ 570
Signison [Member]
Investment in partnerships	279	418
Other Investment [Member]
Investment in partnerships	$ 259	$ 152

Amount of investment in equity method investee and investment in and advance to affiliate.

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 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant