Note 5 - Qualified Affordable Housing Partnership Investments - Generated Tax Credits and Benefits From Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Generated tax credits	$ 125	$ 114	$ 372	$ 342
Tax benefits from taxable losses	30	25	89	75
Raymond James California Housing Opportunities Fund II [Member]
Generated tax credits	43	43	128	128
Tax benefits from taxable losses	7	7	21	22
WNC Institutional Tax Credit Fun 38 L.P. [Member]
Generated tax credits	22	23	66	70
Tax benefits from taxable losses	4	4	12	11
Merritt Community Capital Corporation Fund XV, L.P. [Member]
Generated tax credits	48	48	144	144
Tax benefits from taxable losses	8	8	23	24
California Affordable Housing Fund [Member]
Generated tax credits	1	0	0	0
Tax benefits from taxable losses	6	6	18	18
Boston Capital [Member]
Generated tax credits	11	0	34	0
Tax benefits from taxable losses	$ 5	$ 0	$ 15	$ 0