Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class B [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balances at Dec. 31, 2020	$ 173	$ 24	$ 143,438	$ (17,067)	$ (2,251)	$ 166,325	$ 290,642
Net income (loss)	0	0	0	0	0	60,731	60,731
Share repurchase	(1)					(1,980)
Share repurchase		0	0	(8,367)	0		(10,348)
Other comprehensive loss	0	0	0	0	945	0	945
Stock-based employee compensation expense	0	0	9,059	0	0	0	9,059
Issuance of restricted shares, net	(11)	0	(3,091)	1,772	0	0	(1,330)
Share repurchase		0	0	(8,367)	0		(10,348)
Balances at Dec. 31, 2021	161	24	149,406	(23,662)	(1,306)	225,076	349,699
Net income (loss)	0	0	0	0	0	108,682	108,682
Share repurchase	0	0	0	(84,723)	0	0	(84,723)
Other comprehensive loss	0	0	0	0	2,392	0	2,392
Stock-based employee compensation expense	0	0	6,587	0	0	0	6,587
Issuance of restricted shares, net	0	0	(3,157)	1,551	0	0	(1,606)
Cash dividend	0	0	0	0	0	(4,287)	(4,287)
Share repurchase	0	0	0	(84,723)	0	0	(84,723)
Exercise of stock options	0	0	50	334	0	0	384
Balances at Dec. 31, 2022	161	24	152,886	(106,500)	1,086	329,471	377,128
Net income (loss)	0	0	0	0	0	55,229	55,229
Share repurchase	0	0	0	(25,430)	0	0	(25,430)
Other comprehensive loss	0	0	0	0	(270)	0	(270)
Stock-based employee compensation expense	0	0	7,100	0	0	0	7,100
Issuance of restricted shares, net	0	0	(4,182)	(610)	0	0	(4,792)
Cash dividend	0	0	0	0	0	(5,781)	(5,781)
Share repurchase	0	0	0	(25,430)	0	0	(25,430)
Exercise of stock options	0	0	42	194	0	0	236
Balances at Dec. 31, 2023	$ 161	$ 24	$ 155,846	$ (132,346)	$ 816	$ 378,919	$ 403,420