Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]
BALANCE at Dec. 31, 2021	$ 650,110	$ 887	$ (276,895)	$ 674,242	$ (96)	$ 251,972
BALANCE, shares at Dec. 31, 2021		88,724,000
BALANCE, shares at Dec. 31, 2021			(19,976,000)
Net income	57,845					57,845
Foreign currency translation	(245)				(245)
Unrealized loss on investments, net of tax	(2,833)				(2,833)
Treasury stock purchased	(15,670)		$ (15,670)
Treasury stock purchased, shares			(1,480,000)
Share-based compensation expense	4,316			4,316
Common stock issued	(763)	$ 7	$ (1,612)	842
Common stock issued, shares		635,000	(146,000)
BALANCE at Jun. 30, 2022	692,760	$ 894	$ (294,177)	679,400	(3,174)	309,817
BALANCE, shares at Jun. 30, 2022		89,359,000
BALANCE, shares at Jun. 30, 2022			(21,602,000)
BALANCE at Mar. 31, 2022	678,380	$ 893	$ (282,333)	677,311	(1,541)	284,050
BALANCE, shares at Mar. 31, 2022		89,264,000
BALANCE, shares at Mar. 31, 2022			(20,485,000)
Net income	25,767					25,767
Foreign currency translation	(164)				(164)
Unrealized loss on investments, net of tax	(1,469)				(1,469)
Treasury stock purchased	(11,842)		$ (11,842)
Treasury stock purchased, shares			(1,117,000)
Share-based compensation expense	1,900			1,900
Common stock issued	188	$ 1	$ (2)	189
Common stock issued, shares		95,000
BALANCE at Jun. 30, 2022	692,760	$ 894	$ (294,177)	679,400	(3,174)	309,817
BALANCE, shares at Jun. 30, 2022		89,359,000
BALANCE, shares at Jun. 30, 2022			(21,602,000)
BALANCE at Dec. 31, 2022	$ 725,845	$ 894	$ (301,624)	684,183	(5,447)	347,839
BALANCE, shares at Dec. 31, 2022	89,396,192	89,396,000
BALANCE, shares at Dec. 31, 2022	(22,220,707)		(22,221,000)
Net income	$ 89,157					89,157
Foreign currency translation	23				23
Unrealized loss on investments, net of tax	(197)				(197)
Treasury stock purchased	(2,729)		$ (2,729)
Treasury stock purchased, shares			(221,000)
Treasury stock acquired upon sale of asset, shares			(1,800,000)
Treasury stock acquired upon sale of asset	(22,086)		$ (22,086)
Share-based compensation expense	4,315			4,315
Common stock issued	(1,896)	$ 6	$ (2,209)	307
Common stock issued, shares		620,000	(165,000)
BALANCE at Jun. 30, 2023	$ 792,432	$ 900	$ (328,648)	688,805	(5,621)	436,996
BALANCE, shares at Jun. 30, 2023	90,016,490	90,016,000
BALANCE, shares at Jun. 30, 2023	(24,406,935)		(24,407,000)
BALANCE at Mar. 31, 2023	$ 761,172	$ 899	$ (304,648)	686,719	(4,121)	382,323
BALANCE, shares at Mar. 31, 2023		89,924,000
BALANCE, shares at Mar. 31, 2023			(22,446,000)
Net income	54,673					54,673
Foreign currency translation	(3)				(3)
Unrealized loss on investments, net of tax	(1,497)				(1,497)
Treasury stock purchased	(1,914)		$ (1,914)
Treasury stock purchased, shares			(161,000)
Treasury stock acquired upon sale of asset, shares			(1,800,000)
Treasury stock acquired upon sale of asset	(22,086)		$ (22,086)
Share-based compensation expense	2,021			2,021
Common stock issued	66	$ 1		65
Common stock issued, shares		92,000
BALANCE at Jun. 30, 2023	$ 792,432	$ 900	$ (328,648)	$ 688,805	$ (5,621)	$ 436,996
BALANCE, shares at Jun. 30, 2023	90,016,490	90,016,000
BALANCE, shares at Jun. 30, 2023	(24,406,935)		(24,407,000)