Note 13 - Regulatory Capital and Oversight - Capital Amounts and Ratios (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Common equity tier 1 capital, actual amount	$ 81,340
Common equity tier 1 capital, actual percent of asset	13.06%	[1]
Common equity tier 1 capital, amount required to be adequately capitalized	$ 28,020
Common equity tier 1 capital, percent of assets required to be adequately capitalized	4.50%	[1]
Common equity tier 1 capital, excess capital amount	$ 53,320
Common equity tier 1 capital, excess capital percent of assets	8.56%	[1]
Common equity tier 1 capital, amount to be well capitalized under prompt corrective action provisions	$ 40,473
Common equity tier 1 capital, percent of assets to be well capitalized under prompt corrective action provisions	6.50%	[1]
Tier 1 leverage, actual amount	$ 81,340
Tier 1 leverage, actual percent of asset	11.27%	[1]
Tier 1 leverage, amount required to be adequately capitalized	$ 28,871
Tier 1 leverage, percent of assets required to be adequately capitalized	4.00%	[1]
Tier 1 leverage, excess capital amount	$ 52,469
Tier 1 leverage, excess capital percent of assets	7.27%	[1]
Tier 1 leverage, amount to be well capitalized under prompt corrective action provisions	$ 36,089
Tier 1 leverage, percent of assets to be well capitalized under prompt corrective action provisions	5.00%	[1]
Tier 1 risk-based capital, actual amount	$ 81,340
Tier 1 risk-based capital, actual percent of asset	13.06%	[1]
Tier 1 risk-based capital, amount required to be adequately capitalized	$ 37,360
Tier 1 risk-based capital, percent of assets required to be adequately capitalized	6.00%	[1]
Tier 1 risk-based capital, excess capital amount	$ 43,980
Tier 1 risk-based capital, excess capital percent of assets	7.06%	[1]
Tier 1 risk-based capital, amount to be well capitalized under prompt corrective action provisions	$ 49,813
Tier 1 risk-based capital, percent of assets to be well capitalized under prompt corrective action provisions	8.00%	[1]
Total risk-based capital, actual amount	$ 89,134
Total risk-based capital, actual percent of asset	14.31%	[1]
Total risk-based capital, amount required to be adequately capitalized	$ 49,813
Total risk-based capital, percent of assets required to be adequately capitalized	8.00%	[1]
Total risk-based capital, excess capital amount	$ 39,321
Total risk-based capital, excess capital percent of assets	6.31%	[1]
Total risk-based capital, amount to be well capitalized under prompt corrective action provisions	$ 62,267
Total risk-based capital, percent of assets to be well capitalized under prompt corrective action provisions	10.00%	[1]

[1] Based upon the Bank's adjusted total assets for the purpose of the Tier 1 leverage capital ratio and risk-weighted assets for the purpose of the risk-based capital ratios.