Note 5 - Securities - Securities Held-to-maturity (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
US Government Agencies Debt Securities [Member]
Securities held-to-maturity, AmortizedCosts	$ 3,934,000	$ 13,909,000
Securities held-to-maturity, Gross Unrealized Gains	401,000	288,000
Securities held-to-maturity, Gross Unrealized Losses	0	177,000
Securities held-to-maturity, Fair Values	4,335,000	14,020,000
US States and Political Subdivisions Debt Securities [Member]
Securities held-to-maturity, AmortizedCosts	132,409,000	136,373,000
Securities held-to-maturity, Gross Unrealized Gains	6,781,000	6,179,000
Securities held-to-maturity, Gross Unrealized Losses	25,000	330,000
Securities held-to-maturity, Fair Values	139,165,000	142,222,000
Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, AmortizedCosts	281,000	327,000
Securities held-to-maturity, Gross Unrealized Gains	35,000	36,000
Securities held-to-maturity, Gross Unrealized Losses	0	0
Securities held-to-maturity, Fair Values	316,000	363,000
Corporate Debt Securities [Member]
Securities held-to-maturity, AmortizedCosts	1,423,000	1,419,000
Securities held-to-maturity, Gross Unrealized Gains	39,000	10,000
Securities held-to-maturity, Gross Unrealized Losses	0	2,000
Securities held-to-maturity, Fair Values	1,462,000	1,427,000
Securities held-to-maturity, AmortizedCosts	138,047,000	152,028,000
Securities held-to-maturity, Gross Unrealized Gains	7,256,000	6,513,000
Securities held-to-maturity, Gross Unrealized Losses	25,000	509,000
Securities held-to-maturity, Fair Values	$ 145,278,000	$ 158,032,000