CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury stock [Member]	Accumulated other comprehensive income (loss) [Member]	Parent [Member]	Noncontrolling interest [Member]
Balance, Beginning (in shares) at Dec. 31, 2019		60,283,212
Balance, Beginning at Dec. 31, 2019	$ (238,988)		$ (532,070)	$ 74,334	$ 4,234	$ 218,651	$ (234,851)	$ (4,137)
Net income (loss)	(27,499)			(25,486)			(25,486)
Currency translation adjustment, net	(33,786)					(32,004)	(32,004)	(1,782)
Temporary Equity, Foreign Currency Translation Adjustments	(33,786)
Pension liability adjustments, net of tax	1,308					(1,308)	1,308
Dividends declared	(302)			(302)			(302)
Redemption value adjustment	0
Stock Issued During Period, Shares, Restricted Stock Award, Gross		2,500
Stock-based compensation	490		468		22		490
VIE distributions	559						0	559
Issuance of stock under 401(k) plan		76,280
Issuance of stock under 401(k) plan	(282)		(282)				(282)
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	(27,499)							(2,013)
Balance, Ending (in shares) at Mar. 31, 2020		60,361,992
Balance, Ending at Mar. 31, 2020	(178,922)		(532,820)	100,122	4,212	249,347	(179,139)	217
Balance, Beginning (in shares) at Dec. 31, 2020		61,376,981
Balance, Beginning at Dec. 31, 2020	(176,265)		(532,742)	135,025	1,199	217,254	(179,264)	2,999
Net income (loss)	13,223			13,574			13,574
Currency translation adjustment, net	(27,178)					(26,665)	(26,665)	(513)
Temporary Equity, Foreign Currency Translation Adjustments	(27,178)
Pension liability adjustments, net of tax	873					873	873
Derivative, Gain on Derivative	40						40
Redemption value adjustment	0
Stock Issued During Period, Shares, Restricted Stock Award, Gross		146,322
Stock-based compensation	569		487		82		569
Issuance of stock under 401(k) plan		70,416
Issuance of stock under 401(k) plan	(340)		(340)				(340)
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	13,223							(351)
Balance, Ending (in shares) at Mar. 31, 2021		61,593,719
Balance, Ending at Mar. 31, 2021	$ (164,132)		$ (533,569)	$ 121,451	$ 1,117	$ 243,006	$ (167,995)	$ 3,863