CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balances at Dec. 31, 2017	$ 110,445	$ 74,983	$ (2,073)	$ 183,355
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	14,529	0	14,529
Other comprehensive income (loss)	0	0	(5,067)	(5,067)
Cash dividends paid	0	(5,611)	0	(5,611)
Cash in lieu of fractional share for 5 for 4 stock split	0	(13)	0	(13)
Stock options exercised	168	0	0	168
Stock based compensation expense	217	0	0	217
Balances at Sep. 30, 2018	110,830	83,888	(7,140)	187,578
Balances at Jun. 30, 2018	110,727	80,872	(5,994)	185,605
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	5,021	0	5,021
Other comprehensive income (loss)	0	0	(1,146)	(1,146)
Cash dividends paid	0	(2,005)	0	(2,005)
Stock options exercised	67	0	0	67
Stock based compensation expense	36	0	0	36
Balances at Sep. 30, 2018	110,830	83,888	(7,140)	187,578
Balances at Dec. 31, 2018	133,248	87,333	(3,852)	216,729
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	18,302	0	18,302
Other comprehensive income (loss)	0	0	7,933	7,933
Cash dividends paid	0	(6,588)	0	(6,588)
Stock options exercised	176	0	0	176
Stock based compensation expense	256	0	0	256
Balances at Sep. 30, 2019	133,680	99,047	4,081	236,808
Balances at Jun. 30, 2019	133,597	94,978	3,727	232,302
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	6,267	0	6,267
Other comprehensive income (loss)	0	0	354	354
Cash dividends paid	0	(2,198)	0	(2,198)
Stock options exercised	36	0	0	36
Stock based compensation expense	47	0	0	47
Balances at Sep. 30, 2019	$ 133,680	$ 99,047	$ 4,081	$ 236,808