Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance, shares at Dec. 31, 2020		33,568				1,028
Balance, value at Dec. 31, 2020	$ 743,805	$ 336	$ 304,870	$ 469,943	$ (2,461)	$ (28,883)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,762			12,762
Foreign currency translation adjustment	3,198				3,198
Minimum post retirement benefit plan adjustments, net of taxes	27				27
Stock compensation expense	2,368		2,368
Stock options exercised, shares		25
Stock options exercised	910		910
Net settlement of restricted stock units, shares		118				54
Net settlement of restricted stock units	(4,662)	$ 1	(1)			$ (4,662)
Balance, shares at Mar. 31, 2021		33,711				1,082
Balance, value at Mar. 31, 2021	758,408	$ 337	308,147	482,705	764	$ (33,545)
Balance, shares at Dec. 31, 2021		33,799				1,107
Balance, value at Dec. 31, 2021	825,258	$ 338	314,541	545,572	187	$ (35,380)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,456			15,456
Foreign currency translation adjustment	(227)				(227)
Minimum post retirement benefit plan adjustments, net of taxes	24				24
Stock compensation expense	1,352		1,352
Net settlement of restricted stock units, shares		173				72
Net settlement of restricted stock units	(3,461)	$ 2	(2)			$ (3,461)
Balance, shares at Mar. 31, 2022		33,972				1,179
Balance, value at Mar. 31, 2022	$ 838,402	$ 340	$ 315,891	$ 561,028	$ (16)	$ (38,841)