Note 6 - Investment Securities (Details) - The Amortized Cost and Estimated Fair Value of the Securities Portfolio by Contractual Maturity - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
The Amortized Cost and Estimated Fair Value of the Securities Portfolio by Contractual Maturity [Abstract]
Due in one year or less	$ 11,605
Due in one year or less	11,634
Due in one year or less	0
Due in one year or less	0
Due after one year through five years	163,820
Due after one year through five years	165,394
Due after one year through five years	0
Due after one year through five years	0
Due after five years through ten years	66,708
Due after five years through ten years	68,367
Due after five years through ten years	640
Due after five years through ten years	740
Due after ten years	12,941
Due after ten years	11,749
Due after ten years	2,958
Due after ten years	3,086
Mortgage-backed securities	321,687
Mortgage-backed securities	328,668
Mortgage-backed securities	0
Mortgage-backed securities	0
Total	576,761
Total	585,812
Total	3,598	$ 3,611
Total	$ 3,826	$ 3,809