Note 14 - Regulatory Matters Subsequent Event - Risk-based Capital and Related Ratios (Details) - USD ($) $ in Thousands	Dec. 31, 2018		Dec. 31, 2017		Jan. 01, 2015	Dec. 31, 2014
Total capital (to risk-weighted assets), Amount	$ 117,213		$ 101,135
Total capital (to risk-weighted assets), Ratio	12.69%		12.08%
Total capital (to risk-weighted assets), Minimum required for capital adequacy purposes	8.00%		8.00%		8.00%
Total capital (to risk-weighted assets), Minimum required for capital adequacy purposes with conservation buffer	9.875%		9.25%
Total capital (to risk-weighted assets), To be well capitalized under prompt corrective action	10.00%	[1]	10.00%	[1]	10.00%
Tier I capital (to risk-weighted assets), Amount	$ 105,439		$ 89,220
Tier I capital (to risk-weighted assets), Ratio	11.42%		10.66%
Tier I capital (to risk-weighted assets), Minimum required for capital adequacy purposes	6.00%		6.00%		6.00%	4.00%
Tier I capital (to risk-weighted assets), Minimum required for capital adequacy purposes with conservation buffer	7.875%		7.25%
Tier I capital (to risk-weighted assets), To be well capitalized under prompt corrective action	8.00%	[1]	8.00%	[1]	8.00%	6.00%
Tier I common equity (to risk-weighted assets), Amount	$ 96,692		$ 81,493
Tier I common equity (to risk-weighted assets), Ratio	10.47%		9.74%
Tier I common equity (to risk-weighted assets), Minimum required for capital adequacy purposes	4.50%		4.50%		4.50%
Tier I common equity (to risk-weighted assets), Minimum required for capital adequacy purposes with conservation buffer	6.375%		5.75%
Tier I common equity (to risk-weighted assets), To be well capitalized under prompt corrective action	6.50%	[1]	6.50%	[1]	6.50%
Tier I capital (to average assets), Amount	$ 105,439		$ 89,220
Tier I capital (to average assets), Ratio	8.50%		7.74%
Tier I capital (to average assets), Minimum required for capital adequacy purposes	4.00%		4.00%		4.00%
Tier I capital (to average assets), Minimum required for capital adequacy purposes with conservation buffer	4.00%		4.00%
Tier I capital (to average assets), To be well capitalized under prompt corrective action	5.00%	[1]	5.00%	[1]	5.00%
Total risk-weighted assets, Amount	$ 923,441		$ 837,032
Total average assets, Amount	1,239,898		1,152,776
Subsidiaries [Member]
Total capital (to risk-weighted assets), Amount	$ 112,128		$ 104,272
Total capital (to risk-weighted assets), Ratio	12.17%		12.49%
Tier I capital (to risk-weighted assets), Amount	$ 102,354		$ 94,856
Tier I capital (to risk-weighted assets), Ratio	11.11%		11.36%
Tier I common equity (to risk-weighted assets), Amount	$ 102,354		$ 94,856
Tier I common equity (to risk-weighted assets), Ratio	11.11%		11.36%
Tier I capital (to average assets), Amount	$ 102,354		$ 94,856
Tier I capital (to average assets), Ratio	8.27%		8.24%
Total risk-weighted assets, Amount	$ 921,126		$ 834,959
Total average assets, Amount	$ 1,238,347		$ 1,151,539

[1] Applies to the Bank only.