Note 6 - Other Assets - Summary of Major Components of Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash surrender value of life insurance other than BOLI	$ 19,770		$ 18,426
Net deferred tax asset	25,275		22,320
Investments in tax credit related ventures	11,515		9,552
Swap assets	5,668		8,374
Prepaid assets	3,515		2,935
Trust fees receivable	2,556		2,192
Mortgage servicing rights	4,657	$ 2,865	2,710	$ 1,888	$ 1,446	$ 1,372
Other real estate owned	648		281
Other	13,386		4,575
Total other assets	$ 86,990		$ 71,365