CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2022	$ 734,426	$ 2,236,869	$ (619,862)	$ (3,802)	$ 2,347,631
Balance (in shares) at Dec. 31, 2022	82,593		(31,994)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		(22,071)			(22,071)
Stock awards	$ 57				57
Stock awards (in shares)	130
Employee income tax paid on stock awards			$ (585)		(585)
Employee income tax paid on stock awards (in shares)			(32)
Sale of common stock under employee stock purchase plan	$ 1,218				1,218
Sale of common stock under employee stock purchase plan (in shares)	78
Stock based compensation expense	$ 4,329				4,329
Treasury stock purchases			$ (100,001)		(100,001)
Treasury stock purchases (in shares)			(5,067)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes				1,480	1,480
Balance at Mar. 31, 2023	$ 740,030	2,214,798	$ (720,448)	(2,322)	2,232,058
Balance (in shares) at Mar. 31, 2023	82,801		(37,093)
Balance at Dec. 31, 2022	$ 734,426	2,236,869	$ (619,862)	(3,802)	2,347,631
Balance (in shares) at Dec. 31, 2022	82,593		(31,994)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)					16,826
Net unrealized appreciation (depreciation) on marketable securities, net of taxes					3,618
Balance at Sep. 30, 2023	$ 750,133	2,253,695	$ (866,946)	(184)	2,136,698
Balance (in shares) at Sep. 30, 2023	82,840		(41,620)
Balance at Mar. 31, 2023	$ 740,030	2,214,798	$ (720,448)	(2,322)	2,232,058
Balance (in shares) at Mar. 31, 2023	82,801		(37,093)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		15,419			15,419
Stock based compensation expense	$ 4,246				4,246
Treasury stock purchases			$ (95,998)		(95,998)
Treasury stock purchases (in shares)			(3,335)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes				1,514	1,514
Balance at Jun. 30, 2023	$ 744,276	2,230,217	$ (816,446)	(808)	2,157,239
Balance (in shares) at Jun. 30, 2023	82,801		(40,428)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		23,478			23,478
Sale of common stock under employee stock purchase plan	$ 1,536				1,536
Sale of common stock under employee stock purchase plan (in shares)	39
Stock based compensation expense	$ 4,321				4,321
Treasury stock purchases			$ (50,500)		(50,500)
Treasury stock purchases (in shares)			(1,192)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes				624	624
Balance at Sep. 30, 2023	$ 750,133	2,253,695	$ (866,946)	(184)	2,136,698
Balance (in shares) at Sep. 30, 2023	82,840		(41,620)
Balance at Dec. 31, 2023	$ 754,362	2,271,211	$ (912,396)	325	2,113,502
Balance (in shares) at Dec. 31, 2023	82,840		(42,615)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		60,298			60,298
Stock awards (in shares)	269
Employee income tax paid on stock awards			$ (6,930)		(6,930)
Employee income tax paid on stock awards (in shares)			(117)
Sale of common stock under employee stock purchase plan	$ 1,446				1,446
Sale of common stock under employee stock purchase plan (in shares)	29
Stock based compensation expense	$ 5,510				5,510
Treasury stock purchases			$ (8,750)		(8,750)
Treasury stock purchases (in shares)			(136)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes				(173)	(173)
Balance at Mar. 31, 2024	$ 761,318	2,331,509	$ (928,076)	152	2,164,903
Balance (in shares) at Mar. 31, 2024	83,138		(42,868)
Balance at Dec. 31, 2023	$ 754,362	2,271,211	$ (912,396)	325	2,113,502
Balance (in shares) at Dec. 31, 2023	82,840		(42,615)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)					225,585
Net unrealized appreciation (depreciation) on marketable securities, net of taxes					50
Balance at Sep. 30, 2024	$ 772,320	2,496,796	$ (957,994)	375	2,311,497
Balance (in shares) at Sep. 30, 2024	83,601		(43,263)
Balance at Mar. 31, 2024	$ 761,318	2,331,509	$ (928,076)	152	2,164,903
Balance (in shares) at Mar. 31, 2024	83,138		(42,868)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		75,578			75,578
Stock awards (in shares)	1
Stock based compensation expense	$ 4,812				4,812
Treasury stock purchases			$ (13,453)		(13,453)
Treasury stock purchases (in shares)			(177)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes				(660)	(660)
Balance at Jun. 30, 2024	$ 766,130	2,407,087	$ (941,529)	(508)	2,231,180
Balance (in shares) at Jun. 30, 2024	83,139		(43,045)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		89,709			89,709
Sale of common stock under employee stock purchase plan	$ 1,418				1,418
Sale of common stock under employee stock purchase plan (in shares)	18
Issuance of common stock upon warrant exercise, net (in Shares)	444
Stock based compensation expense	$ 4,772				4,772
Treasury stock purchases			$ (16,465)		(16,465)
Treasury stock purchases (in shares)			(218)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes				883	883
Balance at Sep. 30, 2024	$ 772,320	$ 2,496,796	$ (957,994)	$ 375	$ 2,311,497
Balance (in shares) at Sep. 30, 2024	83,601		(43,263)