Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Average recorded investment in impaired loans(1)	[2]	$ 9,788	[1]	$ 13,344	[1]	$ 11,585	[3]
Income recognized on impaired loans, after designation as impaired		250		528		553	[3]
Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	1,202		781		642
Income recognized on impaired loans, after designation as impaired	[3]	41		57		38
Construction Loans [Member] | Real Estate Construction Portfolio Segment[Member]
Average recorded investment in impaired loans(1)	[2],[3]			3,298
Income recognized on impaired loans, after designation as impaired	[3]			177
Construction, 1-4 Family Residential [Member] | Real Estate Construction Portfolio Segment[Member]
Average recorded investment in impaired loans(1)	[2],[3]					462
Income recognized on impaired loans, after designation as impaired	[3]					10
Closed End Junior Liens [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	159		185		207
Income recognized on impaired loans, after designation as impaired	[3]	9		11		13
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	808		329		74
Income recognized on impaired loans, after designation as impaired	[3]	23		1		4
Multifamily Real Estate [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	491		748		1,366
Income recognized on impaired loans, after designation as impaired	[3]	20		16		12
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	3,038		4,047		4,342
Income recognized on impaired loans, after designation as impaired	[3]	75		200		206
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	2,744		2,638		3,947
Income recognized on impaired loans, after designation as impaired	[3]	54				263
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	1,326		1,282		541
Income recognized on impaired loans, after designation as impaired	[3]	27		64		7
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2]	20	[3]	36		4
Income recognized on impaired loans, after designation as impaired		$ 1	[3]	$ 2			[3]

[1] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

[2] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

[3] Only classes with impaired loans are shown.