Note 13 - Other Comprehensive Income (Loss) - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income tax expense	$ 2,941	$ 3,783	$ 1,030	$ 1,839	$ 2,265	$ 3,555	$ 3,159	$ 3,052	$ 5,542	$ 4,096	$ 4,359	$ 3,142	$ 9,593	$ 12,031	$ 17,139
Reclassification out of Accumulated Other Comprehensive Income [Member]
Income tax expense													0	0	81
Reclassification, net of income taxes													0	0	(151)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Realized loss on sale of securities available for sale													$ 0	$ 0	$ (232)