Note 3 - Investment Securities Available for Sale - Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Government-sponsored mortgage-backed securities	$ 72,432
Government-sponsored mortgage-backed securities	73,300
	72,432	$ 72,965
	73,300	72,370
Within one year
Within one year
After one year through five years	1,602
After one year through five years	1,616
After five years through ten years	16,855
After five years through ten years	17,515
After ten years	7,926
After ten years	8,187
	98,815	96,776
	$ 100,618	$ 96,704