Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cash dividends declared, per share (in dollars per share)	$ 0.60	$ 0.55	$ 1.20	$ 1.10
Issuance of shares of common stock pursuant to dividend reinvestment plan, shares (in shares)	88,953	87,712	180,424	179,199
Issuance of shares of common stock, shares (in shares)	509	919	10,577	12,428
Net change in fair value of available-for-sale securities during the period, taxes	$ 6	$ 220	$ 2,341	$ 2,723
Repurchase of common shares (in shares)				31,774