Note 7 - Components of Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Income (Loss) (Details) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Unrealized holding gain (loss) on available for sale securities, tax	$ (8,992)	$ (3,271)
Reclassification adjustment for gain included in net income, taxes		(1)
AOCI Attributable to Parent [Member]
Unrealized holding gain (loss) on available for sale securities, tax	$ (8,992)	(3,271)
Reclassification adjustment for gain included in net income, taxes		$ (1)

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e640-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=124431353&loc=SL124442407-227067

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17A
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL34724391-108580

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration