CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Treasury - Common Stock	Additional Paid-In Capital	Accumulated Income Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Income	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss)	Cumulative Effect, Period of Adoption, Adjustment [Member]	Total
Balance at Dec. 31, 2019									$ 262,294
Balance at Dec. 31, 2019	$ 40		$ 96,109		$ 179,440		$ (13,295)		262,294
Balance (in shares) at Dec. 31, 2019	40,207
Change in Stockholders' Equity
Net income (loss)					4				4
Foreign currency translation adjustment, net of tax							(4,278)		(4,278)
Restricted stock awards			1,350						1,350
Restricted stock awards, Shares	168
Tax payments for stock issuances			(293)						(293)
Tax payments for stock issuances, Shares	(61)
Pension adjustment, net of tax							(6)		(6)
Balance at Mar. 31, 2020									258,817
Balance at Mar. 31, 2020	$ 40		97,166	$ (254)	179,190	$ 0	(17,579)	$ (254)	258,817
Balance (in shares) at Mar. 31, 2020	40,314
Balance at Dec. 31, 2020	$ 40	$ (5,030)	98,819		173,731		(10,220)		257,340
Balance (in shares) at Dec. 31, 2020	40,103	250
Change in Stockholders' Equity
Net income (loss)					(9,151)				(9,151)
Foreign currency translation adjustment, net of tax					22		(919)		(897)
Restricted stock awards			1,342						1,342
Restricted stock awards, Shares	248
Tax payments for stock issuances			(2,139)						(2,139)
Tax payments for stock issuances, Shares	(86)
Unrealized gains (losses) on available-for-sale securities							(15)		(15)
Balance at Mar. 31, 2021	$ 40	$ (5,030)	$ 98,022		$ 164,602		$ (11,154)		$ 246,480
Balance (in shares) at Mar. 31, 2021	40,265	250