Note 3 - Investment Securities Available-for-Sale (Details) - Securities in Continuous Unrealized Loss Position - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Note 3 - Investment Securities Available-for-Sale (Details) - Securities in Continuous Unrealized Loss Position [Line Items]
Less than 12 Months Estimated Fair Value	$ 99,982	$ 56,619
Less than 12 Months Unrealized Losses	445	242
12 Months or Greater Estimated Fair Value	61,610	98,693
12 Months or Greater Unrealized Losses	948	2,435
Total Estimated Fair Value	161,592	155,312
Total Unrealized Losses	1,393	2,677
US Government Agencies Debt Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities in Continuous Unrealized Loss Position [Line Items]
Less than 12 Months Estimated Fair Value	13,966	2,001
Less than 12 Months Unrealized Losses	90	7
12 Months or Greater Estimated Fair Value		1,750
12 Months or Greater Unrealized Losses		33
Total Estimated Fair Value	13,966	3,751
Total Unrealized Losses	90	40
Residential Mortgage Backed Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities in Continuous Unrealized Loss Position [Line Items]
Less than 12 Months Estimated Fair Value	58,925	49,644
Less than 12 Months Unrealized Losses	182	221
12 Months or Greater Estimated Fair Value	61,610	86,028
12 Months or Greater Unrealized Losses	948	2,295
Total Estimated Fair Value	120,535	135,672
Total Unrealized Losses	1,130	2,516
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities in Continuous Unrealized Loss Position [Line Items]
Less than 12 Months Estimated Fair Value	12,073	4,974
Less than 12 Months Unrealized Losses	95	14
12 Months or Greater Estimated Fair Value		10,915
12 Months or Greater Unrealized Losses		107
Total Estimated Fair Value	12,073	15,889
Total Unrealized Losses	95	$ 121
Corporate Debt Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities in Continuous Unrealized Loss Position [Line Items]
Less than 12 Months Estimated Fair Value	15,018
Less than 12 Months Unrealized Losses	78
Total Estimated Fair Value	15,018
Total Unrealized Losses	$ 78