Note 19 - Fair Value Measurements - Available for Sale Investment Securities Measured At Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities	$ 480,864	$ 582,202
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	833	745
Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	480,031	581,457
Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
US Government-sponsored Enterprises Debt Securities [Member]
Available-for-sale Securities	71,694	106,906
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	71,694	106,906
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities	132,292	150,266
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	132,292	150,266
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Residential Mortgage Backed Securities [Member]
Available-for-sale Securities	224,307	297,861
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	224,307	297,861
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities	45,613	20,584
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	45,613	20,584
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Corporate Debt Securities [Member]
Available-for-sale Securities	6,125	5,840
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	6,125	5,840
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Mutual Funds and Equity Securities [Member]
Available-for-sale Securities	833	745
Mutual Funds and Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	833	745
Mutual Funds and Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	0	0
Mutual Funds and Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	$ 0	$ 0