CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common stock amount	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	Total
Balance at beginning of period at Dec. 31, 2018	$ 32,857	$ 187,653	$ 166,526	$ (11,802)	$ (4,655)	$ 370,579
Increase (Decrease) in Stockholders' Equity
Net income	0	0	7,281	0	0	7,281
Other comprehensive income (loss)	0	0	0	6,174	0	6,174
Cash dividends declared	0	0	(3,105)	0	0	(3,105)
Net issuance to employee stock plans, including related tax effects	0	(173)	0	0	4	(169)
Recognition of stock based compensation	0	263	0	0	0	263
Balance at end of period at Mar. 31, 2019	32,857	187,743	170,702	(5,628)	(4,651)	381,023
Balance at beginning of period at Dec. 31, 2019	32,857	188,536	175,780	3,911	(4,677)	396,407
Increase (Decrease) in Stockholders' Equity
Net income	0	0	7,721	0	0	7,721
Other comprehensive income (loss)	0	0	0	2,279	0	2,279
Cash dividends declared	0	0	(3,429)	0	0	(3,429)
Treasury stock purchased	0	0	0	0	(130)	(130)
Net issuance to employee stock plans, including related tax effects	0	660	0	0	129	789
Recognition of stock based compensation	0	118	0	0	0	118
Balance at end of period at Mar. 31, 2020	$ 32,857	$ 189,314	$ 180,072	$ 6,190	$ (4,678)	$ 403,755