CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash dividends declared per common share (in dollars per share)	$ 0.24	$ 0.24	$ 0.24
Issuance of shares of common stock as s result of stock options exercised (in shares)	41,650	59,393	60,127
Bates Companies
Issuance of common stock, net of issuance costs, shares (in shares)			23,501
Retained Earnings [Member]
Cash dividends declared per common share (in dollars per share)	$ 0.24	$ 0.24	$ 0.24
Common Stock [Member]
Repurchase and cancellation of common stock as a result of share repurchase program (in shares)	100,932
Issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan (in shares)	37,114	28,775	15,528
Issuance of shares of common stock as s result of stock options exercised (in shares)	41,650	59,393	60,127
Exchange of shares of common stock in connection with stock options exercised and restricted stock vested (in shares)	9,057	7,547	21,190
Common Stock [Member] | Springfield Bancshares
Issuance of common stock, net of issuance costs, shares (in shares)			1,699,414
Stock issuance costs			$ 106,327
Common Stock [Member] | Bates Companies
Issuance of shares of common stock as a result of the acquisition, net of issuance cost (in shares)		9,400	23,501
Issuance of common stock, net of issuance costs, shares (in shares)		9,400