Note 18 - Financial Instruments With Off-balance-sheet Risk - (Details Textual) $ in Millions	Dec. 31, 2017 USD ($)
Commitments to Extend Credit [Member]
Contractual Obligation	$ 256.9
Standby and commercial Letters of Credit [Member]
Contractual Obligation	$ 9.5

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

No definition available.

Name:	us-gaap_ContractualObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant