Note 4 -Investment Securities Available-for-sale (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	$ 379,545	$ 390,475
Investment securities available-for-sale, gross unrealized holding gains	975	2,186
Investment securities available-for-sale, gross unrealized holding losses	(7,166)	(7,879)
Investment securities available-for-sale, amortized cost	385,736	396,168
US Government Agencies Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	70,524	76,650
Investment securities available-for-sale, gross unrealized holding gains		36
Investment securities available-for-sale, gross unrealized holding losses	(1,948)	(2,118)
Investment securities available-for-sale, amortized cost	72,472	78,732
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	76,804	72,295
Investment securities available-for-sale, gross unrealized holding gains	717	614
Investment securities available-for-sale, gross unrealized holding losses	(113)	(398)
Investment securities available-for-sale, amortized cost	76,200	72,079
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	142,703	145,301
Investment securities available-for-sale, gross unrealized holding gains	195	561
Investment securities available-for-sale, gross unrealized holding losses	(2,401)	(2,241)
Investment securities available-for-sale, amortized cost	144,909	146,981
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	76,302	77,415
Investment securities available-for-sale, gross unrealized holding gains	29	109
Investment securities available-for-sale, gross unrealized holding losses	(2,292)	(1,846)
Investment securities available-for-sale, amortized cost	78,565	79,152
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	215	2,281
Investment securities available-for-sale, gross unrealized holding gains		263
Investment securities available-for-sale, gross unrealized holding losses	(26)	(891)
Investment securities available-for-sale, amortized cost	241	2,909
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	8,022	8,030
Investment securities available-for-sale, gross unrealized holding gains	6	16
Investment securities available-for-sale, gross unrealized holding losses	(37)	(57)
Investment securities available-for-sale, amortized cost	8,053	8,071
Equity Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale	4,975	8,503
Investment securities available-for-sale, gross unrealized holding gains	28	587
Investment securities available-for-sale, gross unrealized holding losses	(349)	(328)
Investment securities available-for-sale, amortized cost	$ 5,296	$ 8,244

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 1
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