Consolidated Statements Of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2017	$ 376	$ 249,935	$ 37,609	$ 1,857	$ (12,719)	$ 277,058
Balance, shares at Dec. 31, 2017	37,618				(1,386)
Net income (loss) | ASU 606 [Member]			(3,629)			(3,629)
Net income (loss)						(3,629)
Foreign currency translation income (loss) | ASU 606 [Member]				(4,626)		(4,626)
Foreign currency translation income (loss)						(4,626)
Comprehensive income (loss) | ASU 606 [Member]						(8,040)
Comprehensive income (loss)						(8,255)
Equity compensation	$ 1	3,354				3,355
Equity compensation, shares	289
Exercise of options	$ 5	2,222			$ (1,872)	355
Exercise of options, shares	354				(98)
Employee stock purchase plan		588				588
Employee stock purchase plan, shares	37
Redemption and repurchase of stock to cover tax withholdings		(1,811)				(1,811)
Redemption and repurchase of stock to cover tax withholdings, shares	(94)
Balance at Jun. 30, 2018	$ 382	254,288	34,195	(2,769)	$ (14,591)	271,505
Balance, shares at Jun. 30, 2018	38,204				(1,484)
Balance at Mar. 31, 2018	$ 381	252,251	33,969	8,996	$ (14,591)	281,006
Balance, shares at Mar. 31, 2018	38,115				(1,484)
Net income (loss)			226			226
Foreign currency translation income (loss)				(11,765)		(11,765)
Comprehensive income (loss)						(11,539)
Equity compensation		2,001				2,001
Equity compensation, shares	64
Exercise of options	$ 1	336				337
Exercise of options, shares	37
Redemption and repurchase of stock to cover tax withholdings		(300)				(300)
Redemption and repurchase of stock to cover tax withholdings, shares	(12)
Balance at Jun. 30, 2018	$ 382	254,288	34,195	(2,769)	$ (14,591)	271,505
Balance, shares at Jun. 30, 2018	38,204				(1,484)
Balance at Mar. 31, 2018	$ 381	252,251	33,969	8,996	$ (14,591)	281,006
Balance, shares at Mar. 31, 2018	38,115				(1,484)
Balance at Jun. 30, 2019	$ 389	265,694	37,519	(6,858)	$ (14,591)	282,153
Balance, shares at Jun. 30, 2019	38,943				(1,484)
Cumulative effect of adjustment | ASU 606 [Member]			215			215
Balance at Dec. 31, 2018	$ 385	260,361	34,984	(6,072)	$ (14,591)	275,067
Balance, shares at Dec. 31, 2018	38,463				(1,484)
Net income (loss)			2,535			2,535
Foreign currency translation income (loss)				(786)		(786)
Comprehensive income (loss)						1,749
Equity compensation	$ 2	4,417				4,419
Equity compensation, shares	245
Exercise of options	$ 3	3,001				3,004
Exercise of options, shares	301
Employee stock purchase plan		578				578
Employee stock purchase plan, shares	25
Redemption and repurchase of stock to cover tax withholdings	$ (1)	(2,663)				(2,664)
Redemption and repurchase of stock to cover tax withholdings, shares	(91)
Balance at Jun. 30, 2019	$ 389	265,694	37,519	(6,858)	$ (14,591)	282,153
Balance, shares at Jun. 30, 2019	38,943				(1,484)
Balance at Mar. 31, 2019	$ 388	261,991	34,687	(9,853)	$ (14,591)	272,622
Balance, shares at Mar. 31, 2019	38,756				(1,484)
Net income (loss)			2,832			2,832
Foreign currency translation income (loss)				2,995		2,995
Comprehensive income (loss)						5,827
Equity compensation		2,439				2,439
Equity compensation, shares	40
Exercise of options	$ 2	1,551				1,553
Exercise of options, shares	156
Redemption and repurchase of stock to cover tax withholdings	$ (1)	(287)				(288)
Redemption and repurchase of stock to cover tax withholdings, shares	(9)
Balance at Jun. 30, 2019	$ 389	$ 265,694	$ 37,519	$ (6,858)	$ (14,591)	$ 282,153
Balance, shares at Jun. 30, 2019	38,943				(1,484)