Note 10 - Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings - Securities Sold Under Agreements to Repurchase (Details) - Securities Sold under Agreements to Repurchase [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Average balance during the year	$ 62,580	$ 70,187
Average interest rate during the year	0.25%	0.19%
Maximum month-end balance during the year	$ 74,725	$ 75,365