Note 5 - Qualified Affordable Housing Partnership Investments (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Qualified Affordable Housing Project Investments Term	18 years
Proportional Amortization Method Qualified Affordable Housing Project Investments	$ 2,888	$ 3,020
Proportional Amortization Method Qualified Affordable Housing Project Investments Unfunded Liability Obligation	$ 343	$ 343
Minimum [Member]
Qualified Affordable Housing Project Investments Return Rate	3.00%
Maximum [Member]
Qualified Affordable Housing Project Investments Return Rate	5.00%