Note 13 - Regulatory Capital (Details Textual)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2019
Capital Conservation Buffer Required for Capital Adequacy	1.25%
Capital Conservation Buffer Required for Capital Adequacy Annual Increase	0.625%
Savings Bank [Member]
Capital Conservation Buffer	6.60%
Holding Company [Member]
Capital Conservation Buffer	6.61%
Scenario, Forecast [Member]
Capital Conservation Buffer Required for Capital Adequacy		2.50%