Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock
Balance, shares at Dec. 31, 2018			32,887,000						796,000
Balance at Dec. 31, 2018	$ 596,693	$ 1,582	$ 329	$ 282,525	$ 338,995	$ 1,582	$ (7,234)	$ 0	$ (17,922)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	65,091				65,091
Foreign currency translation adjustment	1,766						1,766
Adjustment to post-retirement healthcare benefit liability, net of taxes	77						77
Stock compensation expense	$ 12,570			12,570
Accounting standards update	Accounting Standards Update 2016-02 [Member]
Net settlement of restricted stock units, shares			255,000						110,000
Net settlement of restricted stock units	$ (4,305)		$ 3	(3)					$ (4,305)
Issuance of restricted stock, shares			8,000
Stock options exercised, shares	42,350		42,000
Stock options exercised	$ 490			490
Balance, shares at Dec. 31, 2019			33,192,000						906,000
Balance at Dec. 31, 2019	673,964	$ (291)	$ 332	295,582	405,668	$ (291)	(5,391)		$ (22,227)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	64,566				64,566
Foreign currency translation adjustment	3,301						3,301
Adjustment to post-retirement healthcare benefit liability, net of taxes	(371)						(371)
Stock compensation expense	8,173			8,173
Net settlement of restricted stock units, shares			296,000						122,000
Net settlement of restricted stock units	(6,656)		$ 4	(4)					$ (6,656)
Issuance of restricted stock, shares			4,000
Stock options exercised, shares			76,000
Stock options exercised	1,119			1,119
Balance, shares at Dec. 31, 2020			33,568,000						1,028,000
Balance at Dec. 31, 2020	743,805		$ 336	304,870	469,943		(2,461)		$ (28,883)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	75,629				75,629
Foreign currency translation adjustment	2,512						2,512
Adjustment to post-retirement healthcare benefit liability, net of taxes	136						136
Stock compensation expense	8,652			8,652
Net settlement of restricted stock units, shares			192,000						79,000
Net settlement of restricted stock units	$ (6,497)		$ 2	(2)					$ (6,497)
Issuance of restricted stock, shares			3,000
Stock options exercised, shares	36,500		36,000
Stock options exercised	$ 1,021			1,021
Balance, shares at Dec. 31, 2021			33,799,000						1,107,000
Balance at Dec. 31, 2021	$ 825,258		$ 338	$ 314,541	$ 545,572		$ 187		$ (35,380)