Note 15 - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	$ 0	$ 0
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	24,207,000	49,500,000
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
US Treasury and Government [Member]
Available-for-sale Securities	24,207,000	49,500,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	70,064,000	63,933,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities	70,064,000	63,933,000
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	97,240,000	85,152,000
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Collateralized Mortgage Backed Securities [Member]
Available-for-sale Securities	97,240,000	85,152,000
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	191,511,000	198,585,000
Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Available-for-sale Securities	$ 191,511,000	$ 198,585,000