Note 9 - Employee Benefit Plans - Stock Options Activity (Details) (Parentheticals) - $ / shares	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Weighted average fair value (in dollars per share)	$ 5	$ 4.08

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration