Note 3 - Securities- Securities in a Continuous Loss Position (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Securities available for sale, continuous unrealized loss position, less than 12 months	$ 183,125,000	$ 21,452,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	8,655,000	78,000
Securities available for sale, continuous unrealized loss position, 12 months or more	70,085,000	142,424,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	774,000	1,991,000
Securities available for sale, continuous unrealized loss position	253,210,000	163,876,000
Securities available for sale, continuous unrealized loss position, unrealized loss	9,429,000	2,069,000
US Government Agencies Debt Securities [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	110,160,000	0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	7,172,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more	5,073,000	76,496,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	165,000	1,552,000
Securities available for sale, continuous unrealized loss position	115,233,000	76,496,000
Securities available for sale, continuous unrealized loss position, unrealized loss	7,337,000	1,552,000
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	3,670,000	18,025,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	4,000	69,000
Securities available for sale, continuous unrealized loss position, 12 months or more	37,072,000	34,660,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	419,000	235,000
Securities available for sale, continuous unrealized loss position	40,742,000	52,685,000
Securities available for sale, continuous unrealized loss position, unrealized loss	423,000	304,000
Municipal General Obligation Bonds [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	65,895,000	1,981,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	1,360,000	4,000
Securities available for sale, continuous unrealized loss position, 12 months or more	27,734,000	30,134,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	189,000	201,000
Securities available for sale, continuous unrealized loss position	93,629,000	32,115,000
Securities available for sale, continuous unrealized loss position, unrealized loss	1,549,000	205,000
Municipal Revenue Bonds [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	1,921,000	0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	90,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more	206,000	1,134,000
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	1,000	3,000
Securities available for sale, continuous unrealized loss position	2,127,000	1,134,000
Securities available for sale, continuous unrealized loss position, unrealized loss	91,000	3,000
Other Debt Obligations [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	1,479,000	1,446,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	29,000	5,000
Securities available for sale, continuous unrealized loss position, 12 months or more	0	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	0	0
Securities available for sale, continuous unrealized loss position	1,479,000	1,446,000
Securities available for sale, continuous unrealized loss position, unrealized loss	$ 29,000	$ 5,000