Note 4 - Loans Receivable and Allowance for Loan and Lease Losses - Impaired Loans (Details) - USD ($)	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Impaired loans, related allowance	$ 1,600,000		$ 1,500,000
Impaired loans, recorded investment	30,000,000		21,200,000
With no allowance recorded, average recorded investment	17,798,000	$ 6,977,000
With no allowance recorded, interest income recognized	175,000	35,000
With allowance recorded, average recorded investment	6,445,000	395,000
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	24,243,000	7,372,000
Impaired Loans, interest income recognized	175,000	35,000
Business Activities Loans [Member]
Impaired loans with no related allowance recorded, recorded investment	25,036,000		15,391,000
Impaired loans with no related allowance recorded, unpaid principal balance	25,163,000		16,799,000
Impaired loans with a related allowance recorded, recorded investment	5,015,000		5,827,000
Impaired loans with a related allowance recorded, unpaid principal balance	5,015,000		5,877,000
Impaired loans, related allowance	1,625,000		1,545,000
Impaired loans, recorded investment	30,051,000		21,218,000
Impaired loans, unpaid principal balance	30,178,000		22,676,000
Commercial Real Estate Portfolio Segment [Member]
With no allowance recorded, average recorded investment	6,440,000	2,205,000
With no allowance recorded, interest income recognized	13,000	25,000
With allowance recorded, average recorded investment	472,000
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	6,912,000	2,205,000
Impaired Loans, interest income recognized	13,000	25,000
Commercial Real Estate Portfolio Segment [Member] \| Business Activities Loans [Member]
Impaired loans with no related allowance recorded, recorded investment	12,026,000		4,606,000
Impaired loans with no related allowance recorded, unpaid principal balance	12,145,000		5,109,000
Impaired loans with a related allowance recorded, recorded investment
Impaired loans with a related allowance recorded, unpaid principal balance
Impaired loans, related allowance
Impaired loans, recorded investment	12,026,000		4,606,000
Impaired loans, unpaid principal balance	12,145,000		5,109,000
Residential Portfolio Segment [Member]
With no allowance recorded, average recorded investment	942,000	3,342,000
With no allowance recorded, interest income recognized	4,000	3,000
With allowance recorded, average recorded investment	2,089,000
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	3,031,000	3,342,000
Impaired Loans, interest income recognized	4,000	3,000
Residential Portfolio Segment [Member] \| Business Activities Loans [Member]
Impaired loans with no related allowance recorded, recorded investment	1,760,000		670,000
Impaired loans with no related allowance recorded, unpaid principal balance	1,768,000		703,000
Impaired loans with a related allowance recorded, recorded investment	2,006,000		1,632,000
Impaired loans with a related allowance recorded, unpaid principal balance	2,006,000		1,632,000
Impaired loans, related allowance	563,000		216,000
Impaired loans, recorded investment	3,766,000		2,302,000
Impaired loans, unpaid principal balance	3,774,000		2,335,000
Commercial Portfolio Segment [Member]
With no allowance recorded, average recorded investment	775,000	739,000
With no allowance recorded, interest income recognized
With allowance recorded, average recorded investment	3,863,000	393,000
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	4,638,000	1,132,000
Impaired Loans, interest income recognized
Commercial Portfolio Segment [Member] \| Business Activities Loans [Member]
Impaired loans with no related allowance recorded, recorded investment	1,589,000		488,000
Impaired loans with no related allowance recorded, unpaid principal balance	1,589,000		1,281,000
Impaired loans with a related allowance recorded, recorded investment	3,009,000		4,158,000
Impaired loans with a related allowance recorded, unpaid principal balance	3,009,000		4,208,000
Impaired loans, related allowance	1,062,000		1,299,000
Impaired loans, recorded investment	4,598,000		4,646,000
Impaired loans, unpaid principal balance	4,598,000		5,489,000
Consumer Portfolio Segment [Member]
With no allowance recorded, average recorded investment	841,000	691,000
With no allowance recorded, interest income recognized	8,000	7,000
With allowance recorded, average recorded investment	21,000	2,000
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	862,000	693,000
Impaired Loans, interest income recognized	8,000	7,000
Consumer Portfolio Segment [Member] \| Business Activities Loans [Member]
Impaired loans with no related allowance recorded, recorded investment	861,000		827,000
Impaired loans with no related allowance recorded, unpaid principal balance	861,000		867,000
Impaired loans with a related allowance recorded, recorded investment			37,000
Impaired loans with a related allowance recorded, unpaid principal balance			37,000
Impaired loans, related allowance			30,000
Impaired loans, recorded investment	861,000		864,000
Impaired loans, unpaid principal balance	861,000		904,000
Construction Portfolio Segment [Member]
With no allowance recorded, average recorded investment	8,800,000
With no allowance recorded, interest income recognized	150,000
With allowance recorded, average recorded investment
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	8,800,000
Impaired Loans, interest income recognized	150,000
Construction Portfolio Segment [Member] \| Business Activities Loans [Member]
Impaired loans with no related allowance recorded, recorded investment	8,800,000		8,800,000
Impaired loans with no related allowance recorded, unpaid principal balance	8,800,000		8,839,000
Impaired loans with a related allowance recorded, recorded investment
Impaired loans with a related allowance recorded, unpaid principal balance
Impaired loans, related allowance
Impaired loans, recorded investment	8,800,000		8,800,000
Impaired loans, unpaid principal balance	$ 8,800,000		$ 8,839,000

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=118936363&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=118936363&loc=d3e5258-111524

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