Note 6 - Investment Debt Securities Available-for-sale and Equity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	$ 344,194	$ 374,570
Investment securities available-for-sale, debt securities amortized cost	356,329	380,440
Investment securities, equity securities	9,600	4,975
Investment securities, equity securities gross unrealized holding gains	360	28
Investment securities, equity securities gross unrealized holding losses	(887)	(349)
Investment securities, equity securities amortized cost	10,127	5,296
Total investment debt securities available-for-sale and equity securities	353,794	379,545
Total investment debt securities available-for-sale and equity securities, gross unrealized holding gains	716	975
Total investment debt securities available-for-sale and equity securities, gross unrealized holding losses	(13,378)	(7,166)
Total investment debt securities available-for-sale and equity securities, amortized cost	366,456	385,736
US Government Agencies Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	69,495	70,524
Investment securities available-for-sale, debt securities gross unrealized holding losses	(2,982)	(1,948)
Investment securities available-for-sale, debt securities amortized cost	72,477	72,472
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	70,952	76,804
Investment securities available-for-sale, debt securities gross unrealized holding gains	236	717
Investment securities available-for-sale, debt securities gross unrealized holding losses	(662)	(113)
Investment securities available-for-sale, debt securities amortized cost	71,378	76,200
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	127,426	142,703
Investment securities available-for-sale, debt securities gross unrealized holding gains	95	195
Investment securities available-for-sale, debt securities gross unrealized holding losses	(5,214)	(2,401)
Investment securities available-for-sale, debt securities amortized cost	132,545	144,909
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	71,257	76,302
Investment securities available-for-sale, debt securities gross unrealized holding gains	11	29
Investment securities available-for-sale, debt securities gross unrealized holding losses	(3,525)	(2,292)
Investment securities available-for-sale, debt securities amortized cost	74,771	78,565
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	118	215
Investment securities available-for-sale, debt securities gross unrealized holding losses	(5)	(26)
Investment securities available-for-sale, debt securities amortized cost	123	241
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	4,946	8,022
Investment securities available-for-sale, debt securities gross unrealized holding gains	14	6
Investment securities available-for-sale, debt securities gross unrealized holding losses	(103)	(37)
Investment securities available-for-sale, debt securities amortized cost	$ 5,035	$ 8,053

Equity securities, fair value with change in fair value recognized in net income.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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