CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Impact of adoption of ASC 326	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Impact of adoption of ASC 326	Treasury Stock	Accumulated Other Comprehensive (Loss) Income
Beginning balance at Dec. 31, 2018	$ 244,583		$ 12,835	$ 185,174	$ 80,088		$ (24,352)	$ (9,162)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	18,910				18,910
Other comprehensive income	7,484							7,484
Exercise of stock options	553		24	529
Purchase of treasury stock	(10,067)						(10,067)
Restricted stock grants			31	(31)
Stock based compensation	493			493
Dividends: Common Stock	(6,051)				(6,051)
Ending balance at Sep. 30, 2019	255,905		12,890	186,165	92,947		(34,419)	(1,678)
Beginning balance at Jun. 30, 2019	250,121		12,886	185,918	87,492		(33,549)	(2,626)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	7,530				7,530
Other comprehensive income	948							948
Exercise of stock options	72		4	68
Purchase of treasury stock	(870)						(870)
Stock based compensation	179			179
Dividends: Common Stock	(2,075)				(2,075)
Ending balance at Sep. 30, 2019	255,905		12,890	186,165	92,947		(34,419)	(1,678)
Beginning balance at Dec. 31, 2019	261,551	$ (3,593)	12,905	186,692	98,239	$ (3,593)	(34,492)	(1,793)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	17,487				17,487
Other comprehensive income	11,364							11,364
Exercise of stock options	72		4	68
Purchase of treasury stock	(14,110)						(14,110)
Stock based compensation	494			494
Dividends: Common Stock	(6,412)				(6,412)
Ending balance at Sep. 30, 2020	266,853		12,909	187,254	105,721		(48,602)	9,571
Beginning balance at Jun. 30, 2020	258,875		12,908	187,073	97,788		(47,969)	9,075
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	10,134				10,134
Other comprehensive income	496							496
Exercise of stock options			1	(1)
Purchase of treasury stock	(633)						(633)
Stock based compensation	182			182
Dividends: Common Stock	(2,201)				(2,201)
Ending balance at Sep. 30, 2020	$ 266,853		$ 12,909	$ 187,254	$ 105,721		$ (48,602)	$ 9,571