Note 2 - Investment Securities - Available-for-sale Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Less than one year, available-for-sale securities, amortized cost
Less than one year, available-for-sale securities, fair value
Over one through five years, available-for-sale securities, amortized cost	2,835
Over one through five years, available-for-sale securities, fair value	2,791
Over five through ten years, available-for-sale securities, amortized cost	14,396
Over five through ten years, available-for-sale securities, fair value	14,528
Greater than 10 years, available-for-sale securities, amortized cost	33,329
Greater than 10 years, available-for-sale securities, fair value	32,252
Available-for-sale securities, amortized cost	50,560	$ 55,523
Available-for-sale securities, fair value	$ 49,571	$ 55,344

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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