Note 8 - Loans - Mortgage Loans in Process of Foreclosure (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Residential Portfolio Segment [Member]
Residential real estate in process of foreclosure	$ 1,789	$ 2,738

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL49126937-111524

Name:	us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant