Note 9 - Deposits - (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Percentage of Certificate of Deposit Maturities Year One	71.30%
Percentage of Certificate of Deposit Maturities Year Two and Thereafter	28.70%
Deposits	$ 1,055,533	$ 932,795
Interest-bearing Domestic Deposit, Brokered	78,300	102,800
Interest Bearing Deposits Public Funds Brokered	23,100	27,200
Deposits Public Funds Non-brokered	147,700	113,500
Interest and Non-interest Bearing Deposits Liability [Member] | Top three customers [Member]
Deposits	$ 111,200	$ 114,200
Percentage of Interest and Non-interest Bearing Domestic Deposits to Deposits	10.50%	12.30%