Note 18 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities	$ 328,060,000	$ 346,992,000
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0
US Government Agencies Debt Securities [Member]
Available-for-sale Securities	152,040,000	147,040,000
Collateralized Mortgage Backed Securities [Member]
Available-for-sale Securities	47,392,000	67,074,000
Municipal General Obligation Bonds [Member]
Available-for-sale Securities	119,047,000	122,023,000
Municipal Revenue Bonds [Member]
Available-for-sale Securities	7,631,000	8,914,000
Other Debt Obligations [Member]
Available-for-sale Securities	1,950,000	1,941,000
Fair Value, Measurements, Recurring [Member]
Total	327,976,000	346,739,000
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member]
Interest rate swap agreement	(84,000)	(253,000)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Total	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member]
Interest rate swap agreement	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Total	321,577,000	338,320,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Interest rate swap agreement	(84,000)	(253,000)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Total	6,399,000	8,419,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member]
Interest rate swap agreement	0	0
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member]
Available-for-sale Securities	152,040,000	147,040,000
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	152,040,000	147,040,000
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member]
Available-for-sale Securities	47,392,000	67,074,000
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	47,392,000	67,074,000
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Municipal General Obligation Bonds [Member]
Available-for-sale Securities	119,047,000	122,023,000
Fair Value, Measurements, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	112,648,000	113,604,000
Fair Value, Measurements, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	6,399,000	8,419,000
Fair Value, Measurements, Recurring [Member] | Municipal Revenue Bonds [Member]
Available-for-sale Securities	7,631,000	8,914,000
Fair Value, Measurements, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	7,631,000	8,914,000
Fair Value, Measurements, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Available-for-sale Securities	1,950,000	1,941,000
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	1,950,000	1,941,000
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	$ 0	$ 0