Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balances at Dec. 31, 2019	$ 30	$ 162,154	$ (93,357)	$ (2,209)	$ (33,726)	$ 32,892
Purchase of shares of treasury stock					(4,425)	(4,425)
Issuance of common shares for the exercise of stock options		3,145				3,145
Non-cash stock compensation expense		332				332
Other comprehensive income, foreign currency translation adjustment				(1,124)		(1,124)
Net income			11,755			11,755
Dividends declared common share			(5,278)			(5,278)
Balances at Mar. 31, 2020	30	165,631	(86,880)	(3,333)	(38,151)	37,297
Balances at Dec. 31, 2019	30	162,154	(93,357)	(2,209)	(33,726)	32,892
Other comprehensive income, foreign currency translation adjustment						(414)
Net income						29,048
Balances at Sep. 30, 2020	31	170,052	(69,587)	(2,623)	(41,144)	56,729
Balances at Mar. 31, 2020	30	165,631	(86,880)	(3,333)	(38,151)	37,297
Purchase of shares of treasury stock					(2,077)	(2,077)
Issuance of common shares for the exercise of stock options	1	2,036				2,037
Non-cash stock compensation expense		141				141
Other comprehensive income, foreign currency translation adjustment				461		461
Net income			7,715			7,715
Balances at Jun. 30, 2020	31	167,808	(79,165)	(2,872)	(40,228)	45,574
Purchase of shares of treasury stock					(916)	(916)
Issuance of common shares for the exercise of stock options		1,970				1,970
Non-cash stock compensation expense		274				274
Other comprehensive income, foreign currency translation adjustment				249		249
Net income			9,578			9,578
Balances at Sep. 30, 2020	31	170,052	(69,587)	(2,623)	(41,144)	56,729
Balances at Dec. 31, 2020	31	171,785	(61,375)	(2,399)	(43,727)	64,315
Purchase of shares of treasury stock					(1,210)	(1,210)
Issuance of common shares for the exercise of stock options		911				911
Non-cash stock compensation expense		(54)				(54)
Other comprehensive income, foreign currency translation adjustment				56		56
Net income			9,232			9,232
Balances at Mar. 31, 2021	31	172,642	(52,143)	(2,343)	(44,937)	73,250
Balances at Dec. 31, 2020	31	171,785	(61,375)	(2,399)	(43,727)	64,315
Other comprehensive income, foreign currency translation adjustment						22
Net income						27,833
Balances at Sep. 30, 2021	31	173,112	(42,701)	(2,377)	(44,937)	83,128
Balances at Mar. 31, 2021	31	172,642	(52,143)	(2,343)	(44,937)	73,250
Non-cash stock compensation expense		202				202
Other comprehensive income, foreign currency translation adjustment				74		74
Net income			8,944			8,944
Dividends declared common share			(6,105)			(6,105)
Balances at Jun. 30, 2021	31	172,844	(49,304)	(2,269)	(44,937)	76,365
Issuance of common shares for the exercise of stock options		142				142
Non-cash stock compensation expense		126				126
Other comprehensive income, foreign currency translation adjustment				(108)		(108)
Net income			9,657			9,657
Dividends declared common share			(3,054)			(3,054)
Balances at Sep. 30, 2021	$ 31	$ 173,112	$ (42,701)	$ (2,377)	$ (44,937)	$ 83,128