Note 6 - Other Assets - Amounts Recognized in Net Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Investment loss included in pre-tax income	$ 700	$ 450	$ 1,300	$ 900
Tax credits recognized in provision for income taxes	$ 336	$ 462	$ 672	$ 925

Amount of investment income (loss) of qualified affordable housing project investments accounted for using the equity method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration