Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands		6 Months Ended			12 Months Ended
		Jun. 30, 2019		Jun. 30, 2018	Dec. 31, 2018
Average recorded investment in impaired loans(1)	[1],[2]	$ 6,703		$ 12,326	$ 9,788	[3]
Interest income recognized on impaired loans, after designation as impaired		52		239	250	[3]
Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	939		667	1,202
Interest income recognized on impaired loans, after designation as impaired	[3]	7		15	41
Construction, 1-4 Family Residential [Member] | Real Estate Construction Portfolio Segment[Member]
Average recorded investment in impaired loans(1)	[2],[3]			2,788
Interest income recognized on impaired loans, after designation as impaired	[3]			74
Closed End Junior Liens [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	198		167	159
Interest income recognized on impaired loans, after designation as impaired	[3]	12		5	9
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	447		317	808
Interest income recognized on impaired loans, after designation as impaired	[3]	1		8	23
Multifamily Real Estate [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	466		301	491
Interest income recognized on impaired loans, after designation as impaired	[3]	5		8	20
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	1,187		4,007	3,038
Interest income recognized on impaired loans, after designation as impaired	[3]	15		98	75
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	2,467		2,852	2,744
Interest income recognized on impaired loans, after designation as impaired	[3]			11	54
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Average recorded investment in impaired loans(1)	[2],[3]	990		1,201	1,326
Interest income recognized on impaired loans, after designation as impaired	[3]	12		19	27
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Average recorded investment in impaired loans(1)	[2]	9	[3]	26	20
Interest income recognized on impaired loans, after designation as impaired			[3]	$ 1	$ 1	[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.