Note 6 - Other Assets and Other Liabilities - Amounts Recognized in Net Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Investment loss included in pre-tax income	$ 600	$ 600
Tax credits recognized in provision for income taxes	$ 266	$ 336

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=116633289&loc=SL49122993-202985

Name:	us-gaap_IncomeLossFromAffordableHousingProjectsEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration