Note 4 - Investments (Details Textual) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Other than Temporary Impairment Loss, Investments, Portion in Other Comprehensive Loss, Net of Tax, Attributable to Parent, Held-to-Maturity Securities	$ 0	$ 0	$ 0	$ 0

Amount after tax of amount of other than temporary impairment (OTTI) on investment in held-to-maturity debt security, recognized in other comprehensive loss, attributable to parent entity.

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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration