Note 6 - Investment Securities (Details) - The Amortized Cost and Estimated Fair Value of the Securities Portfolio by Contractual Maturity (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
The Amortized Cost and Estimated Fair Value of the Securities Portfolio by Contractual Maturity [Abstract]
Due in one year or less	$ 13,764
Due in one year or less	13,797
Due in one year or less	0
Due in one year or less	0
Due after one year through five years	154,900
Due after one year through five years	156,299
Due after one year through five years	0
Due after one year through five years	0
Due after five years through ten years	98,195
Due after five years through ten years	99,409
Due after five years through ten years	705
Due after five years through ten years	787
Due after ten years	15,348
Due after ten years	15,036
Due after ten years	3,010
Due after ten years	3,118
Mortgage-backed securities	355,210
Mortgage-backed securities	363,721
Mortgage-backed securities	0
Mortgage-backed securities	0
Total	637,417
Total	648,262
Total	3,715	3,728
Total	$ 3,905	$ 3,923