Note 6 - Investment Securities - The Amortized Costs and Estimated Fair Value of the Securities Portfolio (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available for Sale Securities - Amortized Cost	$ 496,613	$ 486,038
Available for Sale Securities - Gross Unrealized Gains	2,400	2,518
Available for Sale Securities - Gross Unrealized Losses	6,107	7,692
Available-for-sale Securities	492,906	480,864
Held to Maturity Securities - Amortized Cost	3,475	3,488
Held to Maturity Securities - Estimated Fair Value	3,600	3,597
US Government-sponsored Enterprises Debt Securities [Member]
Available for Sale Securities - Amortized Cost	95,120	71,941
Available for Sale Securities - Gross Unrealized Gains	168	213
Available for Sale Securities - Gross Unrealized Losses	405	460
Available-for-sale Securities	94,883	71,694
US States and Political Subdivisions Debt Securities [Member]
Available for Sale Securities - Amortized Cost	130,412	134,055
Available for Sale Securities - Gross Unrealized Gains	857	773
Available for Sale Securities - Gross Unrealized Losses	1,674	2,536
Available-for-sale Securities	129,595	132,292
Held to Maturity Securities - Amortized Cost	3,475	3,488
Held to Maturity Securities - Gross Unrealized Gains	125	109
Held to Maturity Securities - Gross Unrealized Losses	0	0
Held to Maturity Securities - Estimated Fair Value	3,600	3,597
Residential Mortgage Backed Securities [Member]
Available for Sale Securities - Amortized Cost	213,588	225,489
Available for Sale Securities - Gross Unrealized Gains	1,335	1,505
Available for Sale Securities - Gross Unrealized Losses	2,284	2,687
Available-for-sale Securities	212,639	224,307
Commercial Mortgage Backed Securities [Member]
Available for Sale Securities - Amortized Cost	49,039	47,164
Available for Sale Securities - Gross Unrealized Gains	1	6
Available for Sale Securities - Gross Unrealized Losses	1,505	1,557
Available-for-sale Securities	47,535	45,613
Corporate Debt Securities [Member]
Available for Sale Securities - Amortized Cost	7,627	6,565
Available for Sale Securities - Gross Unrealized Gains	1	1
Available for Sale Securities - Gross Unrealized Losses	235	441
Available-for-sale Securities	7,393	6,125
Mutual Funds and Equity Securities [Member]
Available for Sale Securities - Amortized Cost	827	824
Available for Sale Securities - Gross Unrealized Gains	38	20
Available for Sale Securities - Gross Unrealized Losses	4	11
Available-for-sale Securities	$ 861	$ 833

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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