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, 2018	$ 30	$ 157,312	$ (106,339)	$ (2,916)	$ (29,004)	$ 19,083
Purchase of shares treasury stock					(1,116)	(1,116)
Issuance of common shares for the exercise of stock options		633				633
Non-cash stock compensation expense		302				302
Dividends declared			(4,724)			(4,724)
Other comprehensive loss, foreign currency translation adjustment				365		365
Net income			8,196			8,196
Balances at Mar. 31, 2019	30	158,247	(102,867)	(2,551)	(30,120)	22,739
Balances at Dec. 31, 2018	30	157,312	(106,339)	(2,916)	(29,004)	19,083
Other comprehensive loss, foreign currency translation adjustment						474
Net income						23,708
Balances at Sep. 30, 2019	30	160,524	(96,817)	(2,442)	(32,320)	28,975
Balances at Mar. 31, 2019	30	158,247	(102,867)	(2,551)	(30,120)	22,739
Purchase of shares treasury stock					(137)	(137)
Issuance of common shares for the exercise of stock options		137				137
Non-cash stock compensation expense		307				307
Dividends declared			(4,727)			(4,727)
Other comprehensive loss, foreign currency translation adjustment				255		255
Net income			7,393			7,393
Balances at Jun. 30, 2019	30	158,691	(100,201)	(2,296)	(30,257)	25,967
Purchase of shares treasury stock					(2,063)	(2,063)
Issuance of common shares for the exercise of stock options		1,525				1,525
Non-cash stock compensation expense		308				308
Dividends declared			(4,735)			(4,735)
Other comprehensive loss, foreign currency translation adjustment				(146)		(146)
Net income			8,119			8,119
Balances at Sep. 30, 2019	30	160,524	(96,817)	(2,442)	(32,320)	28,975
Balances at Dec. 31, 2019	30	162,154	(93,357)	(2,209)	(33,726)	32,892
Purchase of shares 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
Dividends declared			(5,278)			(5,278)
Other comprehensive loss, foreign currency translation adjustment				(1,124)		(1,124)
Net income			11,755			11,755
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 loss, 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 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 loss, 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 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 loss, 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