Note 12 - Regulatory Capital - Capital Amounts and Ratios (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Common equity tier 1 capital, actual amount	$ 77,931
Common equity tier 1 capital, actual percent of asset	12.67%	[1]
Common equity tier 1 capital, amount required to be adequately capitalized	$ 27,669
Common equity tier 1 capital, percent of assets required to be adequately capitalized	4.50%	[1]
Common equity tier 1 capital, excess capital amount	$ 50,262
Common equity tier 1 capital, excess capital percent of assets	8.17%	[1]
Common equity tier 1 capital, amount to be well capitalized under prompt corrective action provisions	$ 39,966
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	$ 77,931
Tier 1 leverage, actual percent of asset	10.97%	[1]
Tier 1 leverage, amount required to be adequately capitalized	$ 28,408
Tier 1 leverage, percent of assets required to be adequately capitalized	4.00%	[1]
Tier 1 leverage, excess capital amount	$ 49,523
Tier 1 leverage, excess capital percent of assets	6.97%	[1]
Tier 1 leverage, amount to be well capitalized under prompt corrective action provisions	$ 35,510
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	$ 77,931
Tier 1 risk-based capital, actual percent of asset	12.67%	[1]
Tier 1 risk-based capital, amount required to be adequately capitalized	$ 38,892
Tier 1 risk-based capital, percent of assets required to be adequately capitalized	6.00%	[1]
Tier 1 risk-based capital, excess capital amount	$ 41,039
Tier 1 risk-based capital, excess capital percent of assets	6.67%	[1]
Tier 1 risk-based capital, amount to be well capitalized under prompt corrective action provisions	$ 49,189
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	$ 85,634
Total risk-based capital, actual percent of asset	13.93%	[1]
Total risk-based capital, amount required to be adequately capitalized	$ 49,189
Total risk-based capital, percent of assets required to be adequately capitalized	8.00%	[1]
Total risk-based capital, excess capital amount	$ 36,445
Total risk-based capital, excess capital percent of assets	5.93%	[1]
Total risk-based capital, amount to be well capitalized under prompt corrective action provisions	$ 61,486
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.