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
Beginning balance (in shares) at Dec. 31, 2019		24,118	(10,174)
Beginning 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
Ending balance (in shares) at Mar. 31, 2020		24,256	(10,343)
Ending balance at Mar. 31, 2020	269,959	$ 243	$ (284,108)	291,350	(29,790)	292,264
Beginning balance (in shares) at Dec. 31, 2019		24,118	(10,174)
Beginning 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)	26,414
Currency translation adjustment	(2,774)
Change in foreign currency translation due to sale of Argentina subsidiary	$ 0
Purchase of treasury shares (in shares)	(263)
Purchase of treasury shares	$ (9,822)
Ending balance (in shares) at Sep. 30, 2020		24,293	(10,437)
Ending balance at Sep. 30, 2020	296,555	$ 243	$ (287,639)	296,674	(25,555)	312,832
Beginning balance (in shares) at Mar. 31, 2020		24,256	(10,343)
Beginning 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			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
Ending balance (in shares) at Jun. 30, 2020		24,269	(10,346)
Ending balance at Jun. 30, 2020	286,132	$ 243	$ (284,222)	294,007	(30,560)	306,664
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	6,168					6,168
Currency translation adjustment	5,005				5,005
Change in foreign currency translation due to sale of Argentina subsidiary	0
Shares issued for employee benefit plan and compensation (in shares)		15
Shares issued for employee benefit plan and compensation	220			220
Purchase of treasury shares (in shares)			(91)
Purchase of treasury shares	(3,417)		$ (3,417)
Shares issued to directors (in shares)		9
Shares issued to directors	0
Employee and director stock-based compensation	2,260			2,260
Performance-based common stock warrants	187			187
Ending balance (in shares) at Sep. 30, 2020		24,293	(10,437)
Ending balance at Sep. 30, 2020	296,555	$ 243	$ (287,639)	296,674	(25,555)	312,832
Beginning balance (in shares) at Dec. 31, 2020		24,392	(10,618)
Beginning balance at Dec. 31, 2020	313,301	$ 244	$ (295,495)	302,084	(18,522)	324,990
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	6,993					6,993
Currency translation adjustment	(2,868)				(2,868)
Shares issued for employee benefit plan and compensation (in shares)		160
Shares issued for employee benefit plan and compensation	410	$ 2		408
Purchase of treasury shares (in shares)			(191)
Purchase of treasury shares	(10,951)		$ (10,951)
Stock options exercised (in shares)		22
Stock options exercised	991			991
Shares issued to directors (in shares)		7
Shares issued to directors	0
Employee and director stock-based compensation	2,600			2,600
Performance-based common stock warrants	143			143
Ending balance (in shares) at Mar. 31, 2021		24,581	(10,809)
Ending balance at Mar. 31, 2021	310,619	$ 246	$ (306,446)	306,226	(21,390)	331,983
Beginning balance (in shares) at Dec. 31, 2020		24,392	(10,618)
Beginning balance at Dec. 31, 2020	313,301	$ 244	$ (295,495)	302,084	(18,522)	324,990
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	11,631
Currency translation adjustment	(784)
Change in foreign currency translation due to sale of Argentina subsidiary	$ 5,425
Purchase of treasury shares (in shares)	(859)
Purchase of treasury shares	$ (44,217)
Stock options exercised (in shares)	22
Ending balance (in shares) at Sep. 30, 2021		24,628	(11,477)
Ending balance at Sep. 30, 2021	$ 295,238	$ 246	$ (339,712)	311,964	(13,881)	336,621
Beginning balance (in shares) at Mar. 31, 2021		24,581	(10,809)
Beginning balance at Mar. 31, 2021	310,619	$ 246	$ (306,446)	306,226	(21,390)	331,983
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	5,593					5,593
Currency translation adjustment	4,043				4,043
Shares issued for employee benefit plan and compensation (in shares)		15
Shares issued for employee benefit plan and compensation	271			271
Purchase of treasury shares (in shares)			(320)
Purchase of treasury shares	(15,733)		$ (15,733)
Shares issued to directors (in shares)		8
Shares issued to directors	0
Employee and director stock-based compensation	2,444			2,444
Performance-based common stock warrants	131			131
Ending balance (in shares) at Jun. 30, 2021		24,604	(11,129)
Ending balance at Jun. 30, 2021	307,368	$ 246	$ (322,179)	309,072	(17,347)	337,576
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(955)					(955)
Currency translation adjustment	(1,959)				(1,959)
Change in foreign currency translation due to sale of Argentina subsidiary	5,425				5,425
Shares issued for employee benefit plan and compensation (in shares)		16
Shares issued for employee benefit plan and compensation	296			296
Purchase of treasury shares (in shares)			(348)
Purchase of treasury shares	(17,533)		$ (17,533)
Shares issued to directors (in shares)		8
Shares issued to directors	0
Employee and director stock-based compensation	2,472			2,472
Performance-based common stock warrants	124			124
Ending balance (in shares) at Sep. 30, 2021		24,628	(11,477)
Ending balance at Sep. 30, 2021	$ 295,238	$ 246	$ (339,712)	$ 311,964	$ (13,881)	$ 336,621