Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2018	$ 571,535	$ 103,801	$ 467,783	$ (49)
Balance, Shares at Dec. 31, 2018		24,182,000
Net income	96,806		96,806
Share-based compensation	5,892	$ 5,892
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		114,000
Taxes paid related to net share settlement of stock awards	(3,333)	$ (3,333)
Dividends accrued at $1.50, $1.68 and $1.74 per share in 2019, 2020 and 2021	(36,843)		(36,843)
Other comprehensive (loss) income	(21)			(21)
Balance at Dec. 31, 2019	634,036	$ 106,360	527,746	(70)
Balance, Shares at Dec. 31, 2019		24,296,000
Net income	101,984		101,984
Share-based compensation	5,549	$ 5,549
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		114,000
Repurchased common stock	(13,617)	$ (1,244)	(12,373)
Repurchased common stock, Shares		(282,000)
Taxes paid related to net share settlement of stock awards	(4,376)	$ (4,376)
Dividends accrued at $1.50, $1.68 and $1.74 per share in 2019, 2020 and 2021	(40,938)		(40,938)
Other comprehensive (loss) income	(34)			(34)
Balance at Dec. 31, 2020	$ 682,604	$ 106,289	576,419	(104)
Balance, Shares at Dec. 31, 2020	24,128,000	24,128,000
Net income	$ 89,705		89,705
Share-based compensation	7,666	$ 7,666
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		132,000
Taxes paid related to net share settlement of stock awards	(5,345)	$ (5,345)
Dividends accrued at $1.50, $1.68 and $1.74 per share in 2019, 2020 and 2021	(42,659)		(42,659)
Other comprehensive (loss) income	50			50
Balance at Dec. 31, 2021	$ 732,021	$ 108,610	$ 623,465	$ (54)
Balance, Shares at Dec. 31, 2021	24,260,000	24,260,000