Note 10 - Financial Instrument Commitments (Details Textual) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Standby letters of credit	$ 11,110
Maximum [Member]
Commitments And Contingencies Disclosure [Line Items]
Standby letters of credit expiration period	1 year