Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2018	20,000,022
Balance at Dec. 31, 2018	$ 288,610	$ 5,659	$ 81,618	$ 72	$ (1,338)	$ 374,621
Net income	0	0	28,534	0	0	28,534
Stock-based compensation	0	543	0	0	0	543
Cash dividend	0	0	(6,030)	0	0	(6,030)
Other comprehensive income, net of taxes	$ 0	0	0	0	1,669	1,669
Stock options exercised, net of expense recognized (in shares)	200,629
Stock options exercised, net of expense recognized	$ 2,694	0	0	0	0	2,694
Repurchase of common stock (in shares)	(169,785)
Repurchase of common stock	$ (2,442)	0	(748)	0	0	(3,190)
Balance (in shares) at Sep. 30, 2019	20,030,866
Balance at Sep. 30, 2019	$ 288,862	6,202	103,374	72	331	398,841
Balance (in shares) at Dec. 31, 2018	20,000,022
Balance at Dec. 31, 2018	$ 288,610	5,659	81,618	72	(1,338)	$ 374,621
Stock options exercised, net of expense recognized (in shares)						200,629
Balance (in shares) at Dec. 31, 2019	20,030,866					20,030,866
Balance at Dec. 31, 2019	$ 290,395	4,938	112,046	72	239	$ 407,690
Balance (in shares) at Jun. 30, 2019	20,077,524
Balance at Jun. 30, 2019	$ 289,577	6,055	98,126	72	(10)	393,820
Net income	0	0	8,012	0	0	8,012
Stock-based compensation	0	147	0	0	0	147
Cash dividend	0	0	(2,016)	0	0	(2,016)
Other comprehensive income, net of taxes	$ 0	0	0	0	341	341
Stock options exercised, net of expense recognized (in shares)	123,127
Stock options exercised, net of expense recognized	$ 1,727	0	0	0	0	1,727
Repurchase of common stock (in shares)	(169,785)
Repurchase of common stock	$ (2,442)	0	(748)	0	0	(3,190)
Balance (in shares) at Sep. 30, 2019	20,030,866
Balance at Sep. 30, 2019	$ 288,862	6,202	103,374	72	331	$ 398,841
Balance (in shares) at Dec. 31, 2019	20,030,866					20,030,866
Balance at Dec. 31, 2019	$ 290,395	4,938	112,046	72	239	$ 407,690
Net income	0	0	21,781	0	0	21,781
Stock-based compensation	0	493	0	0	0	493
Cash dividend	$ 0	0	(4,782)	0	0	(4,782)
Restricted stock vested (in shares)	0
Restricted stock vested	$ 425	(425)				0
Other comprehensive income, net of taxes	$ 0	0	0	0	776	$ 776
Stock options exercised, net of expense recognized (in shares)	56,498					56,498
Stock options exercised, net of expense recognized	$ 978	(266)	0	0	0	$ 712
Repurchase of common stock (in shares)	(348,084)
Repurchase of common stock	$ (5,023)	0	(231)	0	0	$ (5,254)
Balance (in shares) at Sep. 30, 2020	19,739,280					19,739,280
Balance at Sep. 30, 2020	$ 286,775	4,740	128,814	72	1,015	$ 421,416
Balance (in shares) at Jun. 30, 2020	19,739,280
Balance at Jun. 30, 2020	$ 286,350	4,999	121,478	72	1,126	414,025
Net income	0	0	8,520	0	0	8,520
Stock-based compensation	0	166	0	0	0	166
Cash dividend	$ 0	0	(1,184)	0	0	(1,184)
Restricted stock vested (in shares)	0
Restricted stock vested	$ 425	(425)	0	0	0	0
Other comprehensive income, net of taxes	$ 0	0	0	0	(111)	$ (111)
Balance (in shares) at Sep. 30, 2020	19,739,280					19,739,280
Balance at Sep. 30, 2020	$ 286,775	$ 4,740	$ 128,814	$ 72	$ 1,015	$ 421,416