Note 14 - Concentrations of Credit Risk (Details Textual) - Credit Concentration Risk [Member] - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Commercial Real Estate Loans [Member]
Concentration Risk, Percentage	50.00%	50.00%
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	$ 365,373	$ 353,546
College Housing and Professional Office Buildings [Member]
Concentration Risk, Percentage	25.00%	26.00%
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	$ 181,705	$ 184,203
Residential [Member]
Concentration Risk, Percentage	25.00%	25.00%
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	$ 181,472	$ 175,456

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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