CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock Issued	Common Stock in Treasury	Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance (in shares) at Dec. 31, 2018		23,933	(10,116)
Balance at Dec. 31, 2018	$ 262,960	$ 239	$ (275,889)	$ 276,103	$ (20,281)	$ 282,788
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(1,005)					(1,005)
Currency translation adjustment	1,733				1,733
Shares issued for employee benefit plan and compensation (in shares)		78
Shares issued for employee benefit plan and compensation	347	$ 1		346
Purchase of treasury shares (in shares)			(43)
Purchase of treasury shares	(1,215)		$ (1,215)
Shares issued to directors (in shares)		8
Shares issued to directors	0	$ 0		0
Employee and director stock-based compensation	1,918			1,918
Performance-based common stock warrants	434			434
Balance (in shares) at Mar. 31, 2019		24,019	(10,159)
Balance at Mar. 31, 2019	265,172	$ 240	$ (277,104)	278,801	(18,548)	281,783
Balance (in shares) at Dec. 31, 2018		23,933	(10,116)
Balance at Dec. 31, 2018	262,960	$ 239	$ (275,889)	276,103	(20,281)	282,788
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(6,066)
Currency translation adjustment	$ (100)
Purchase of treasury shares (in shares)	(48)
Purchase of treasury shares	$ (1,404)
Balance (in shares) at Jun. 30, 2019		24,043	(10,164)
Balance at Jun. 30, 2019	260,871	$ 240	$ (277,293)	281,583	(20,381)	276,722
Balance (in shares) at Mar. 31, 2019		24,019	(10,159)
Balance at Mar. 31, 2019	265,172	$ 240	$ (277,104)	278,801	(18,548)	281,783
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(5,061)					(5,061)
Currency translation adjustment	(1,833)				(1,833)
Shares issued for employee benefit plan and compensation (in shares)		17
Shares issued for employee benefit plan and compensation	273	$ 0		273
Purchase of treasury shares (in shares)			(5)
Purchase of treasury shares	(189)		$ (189)
Shares issued to directors (in shares)		7
Shares issued to directors	0	$ 0		0
Employee and director stock-based compensation	2,273			2,273
Performance-based common stock warrants	236			236
Balance (in shares) at Jun. 30, 2019		24,043	(10,164)
Balance at Jun. 30, 2019	260,871	$ 240	$ (277,293)	281,583	(20,381)	276,722
Balance (in shares) at Dec. 31, 2019		24,118	(10,174)
Balance at Dec. 31, 2019	274,399	$ 241	$ (277,817)	288,338	(22,781)	286,418
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	5,846					5,846
Currency translation adjustment	(7,009)				(7,009)
Shares issued for employee benefit plan and compensation (in shares)		129
Shares issued for employee benefit plan and compensation	527	$ 1		526
Purchase of treasury shares (in shares)			(169)
Purchase of treasury shares	(6,291)		$ (6,291)
Shares issued to directors (in shares)		9
Shares issued to directors	0	$ 1		(1)
Employee and director stock-based compensation	2,303			2,303
Performance-based common stock warrants	184			184
Balance (in shares) at Mar. 31, 2020		24,256	(10,343)
Balance at Mar. 31, 2020	269,959	$ 243	$ (284,108)	291,350	(29,790)	292,264
Balance (in shares) at Dec. 31, 2019		24,118	(10,174)
Balance at Dec. 31, 2019	274,399	$ 241	$ (277,817)	288,338	(22,781)	286,418
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	20,246
Currency translation adjustment	$ (7,779)
Purchase of treasury shares (in shares)	(172)
Purchase of treasury shares	$ (6,405)
Balance (in shares) at Jun. 30, 2020		24,269	(10,346)
Balance at Jun. 30, 2020	286,132	$ 243	$ (284,222)	294,007	(30,560)	306,664
Balance (in shares) at Mar. 31, 2020		24,256	(10,343)
Balance at Mar. 31, 2020	269,959	$ 243	$ (284,108)	291,350	(29,790)	292,264
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	14,400					14,400
Currency translation adjustment	(770)				(770)
Shares issued for employee benefit plan and compensation (in shares)		13
Shares issued for employee benefit plan and compensation	212	$ 0		212
Purchase of treasury shares (in shares)			(3)
Purchase of treasury shares	(114)		$ (114)
Employee and director stock-based compensation	2,291			2,291
Performance-based common stock warrants	154			154
Balance (in shares) at Jun. 30, 2020		24,269	(10,346)
Balance at Jun. 30, 2020	$ 286,132	$ 243	$ (284,222)	$ 294,007	$ (30,560)	$ 306,664