Note 2 - Investment Securities - Unrealized Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Securities in a continuous unrealized loss position, less than 12 months, fair value	$ 72,259	$ 73,386
Securities in a continuous unrealized loss position, less than 12 months, unrealized losses	555	404
Securities in a continuous unrealized loss position, 12 months or more, fair value	7,795	13,921
Securities in a continuous unrealized loss position, 12 months or more, unrealized losses	204	236
Securities in a continuous unrealized loss position, fair value	80,054	87,307
Securities in a continuous unrealized loss position, unrealized losses	759	640
US Government Agencies Debt Securities [Member]
Securities in a continuous unrealized loss position, less than 12 months, fair value	6,766	3,785
Securities in a continuous unrealized loss position, less than 12 months, unrealized losses	47	12
Securities in a continuous unrealized loss position, 12 months or more, fair value		0
Securities in a continuous unrealized loss position, 12 months or more, unrealized losses		0
Securities in a continuous unrealized loss position, fair value	6,766	3,785
Securities in a continuous unrealized loss position, unrealized losses	47	12
Collateralized Mortgage Backed Securities [Member]
Securities in a continuous unrealized loss position, less than 12 months, fair value	27,586	51,956
Securities in a continuous unrealized loss position, less than 12 months, unrealized losses	163	264
Securities in a continuous unrealized loss position, 12 months or more, fair value		2,641
Securities in a continuous unrealized loss position, 12 months or more, unrealized losses		7
Securities in a continuous unrealized loss position, fair value	27,586	54,597
Securities in a continuous unrealized loss position, unrealized losses	163	271
US States and Political Subdivisions Debt Securities [Member]
Securities in a continuous unrealized loss position, less than 12 months, fair value	24,156	1,530
Securities in a continuous unrealized loss position, less than 12 months, unrealized losses	319	8
Securities in a continuous unrealized loss position, 12 months or more, fair value	0	0
Securities in a continuous unrealized loss position, 12 months or more, unrealized losses	0	0
Securities in a continuous unrealized loss position, fair value	24,156	1,530
Securities in a continuous unrealized loss position, unrealized losses	319	8
Corporate Debt Securities [Member]
Securities in a continuous unrealized loss position, less than 12 months, fair value	13,751	16,115
Securities in a continuous unrealized loss position, less than 12 months, unrealized losses	26	120
Securities in a continuous unrealized loss position, 12 months or more, fair value	7,795	11,280
Securities in a continuous unrealized loss position, 12 months or more, unrealized losses	204	229
Securities in a continuous unrealized loss position, fair value	21,546	27,395
Securities in a continuous unrealized loss position, unrealized losses	$ 230	$ 349