Note 5 - Credit Quality - Loans Modified as Troubled Debt Restructurings (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Total contracts		2	6
Pre-modification recorded investment		$ 52	$ 243
Post-modification recorded investment	[1]	$ 52	$ 243
Total contracts, payment default		1	1
Recorded investment, payment default		$ 521	$ 14
Single Family Owner Occupied [Member]
Total contracts, payment default		1	1
Recorded investment, payment default		$ 521	$ 14
Below Market Interest Rate [Member] | Single Family Owner Occupied [Member]
Total contracts		1
Pre-modification recorded investment		$ 11
Post-modification recorded investment	[1]	$ 11
Below Market Interest Rate and Extended Payment Term [Member] | Single Family Owner Occupied [Member]
Total contracts		1	5
Pre-modification recorded investment		$ 41	$ 207
Post-modification recorded investment	[1]	$ 41	$ 207
Below Market Interest Rate and Extended Payment Term [Member] | Consumer Loans [Member]
Total contracts			1
Pre-modification recorded investment			$ 36
Post-modification recorded investment			$ 36

[1] Represents the loan balance immediately following modification