CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Total
Balance at Dec. 31, 2018	$ 191	$ 30,111	$ 286,756	$ (15,876)	$ 301,182
Balance (in shares) at Dec. 31, 2018	17,919,021
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, net		979		3,099	4,078
Exercise of stock options, net (in shares)	222,362
Stock-based compensation expense		4,125			4,125
Net income			31,816		31,816
Balance at Dec. 31, 2019	$ 191	35,215	318,572	(12,777)	341,201
Balance (in shares) at Dec. 31, 2019	18,141,383
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, net		(4,650)		3,905	(745)
Exercise of stock options, net (in shares)	284,747
Stock-based compensation expense		3,855			3,855
Capital contribution		78			78
Net income			23,678		23,678
Balance at Dec. 31, 2020	$ 191	34,498	342,250	(8,872)	$ 368,067
Balance (in shares) at Dec. 31, 2020	18,426,130				18,426,130
Increase (Decrease) in Stockholders' Equity
Exercise of stock options, net		2,868		4,531	$ 7,399
Exercise of stock options, net (in shares)	338,410
Stock-based compensation expense		4,060			4,060
Net income			68,488		68,488
Balance at Dec. 31, 2021	$ 191	$ 41,426	$ 410,738	$ (4,341)	$ 448,014
Balance (in shares) at Dec. 31, 2021	18,764,540				18,764,540