Note 3 - Loans and Allowance for Credit Losses - Impaired Loans, Supplemental Schedule (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Average Recorded Investment	$ 16,075
Recognized Interest Income	283
Commercial Portfolio Segment [Member]
Average Recorded Investment	8,412
Recognized Interest Income	140
Commercial Real Estate Portfolio Segment [Member]
Average Recorded Investment	7,428
Recognized Interest Income	139
Residential Portfolio Segment [Member]
Average Recorded Investment	191
Recognized Interest Income	3
Consumer Portfolio Segment [Member]
Average Recorded Investment	44
Recognized Interest Income	$ 1

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration