Note 10 - Derivatives and Risk Management Activities - Amounts Recorded in Statement of Financial Condition (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other Assets [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Asset, Fair Value	$ 8	$ 5
Derivative Asset, Notional Amount	2,775	1,807
Other Assets [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Asset, Fair Value	19	19
Derivative Asset, Notional Amount	6,481	4,566
Other Assets [Member] | Interest Rate Lock Commitments [Member]
Derivative Asset, Fair Value	417	363
Derivative Asset, Notional Amount	19,367	16,366
Other Liabilities [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Liability, Fair Value	90	93
Derivative Liability, Notional Amount	16,592	14,983
Other Liabilities [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Liability, Fair Value	103	195
Derivative Liability, Notional Amount	21,731	36,223
Other Liabilities [Member] | Interest Rate Lock Commitments [Member]
Derivative Liability, Fair Value		1
Derivative Liability, Notional Amount		$ 424