Note 10 - Derivatives and Risk Management Activities - Amounts Recorded in Statement of Financial Condition (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Other Assets [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Asset, Fair Value	$ 1	$ 5
Derivative Asset, Notional Amount	363	1,807
Other Assets [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Asset, Fair Value	6	19
Derivative Asset, Notional Amount	1,091	4,566
Other Assets [Member] | Interest Rate Lock Commitments [Member]
Derivative Asset, Fair Value	714	363
Derivative Asset, Notional Amount	32,937	16,366
Other Liabilities [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Liability, Fair Value	210	93
Derivative Liability, Notional Amount	33,261	14,983
Other Liabilities [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Liability, Fair Value	301	195
Derivative Liability, Notional Amount	33,168	36,223
Other Liabilities [Member] | Interest Rate Lock Commitments [Member]
Derivative Liability, Fair Value	3	1
Derivative Liability, Notional Amount	$ 687	$ 424