CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2020	$ 44,132	$ 555	$ 95,528	$ (626,984)	$ 575,033
Balance (shares) at Dec. 31, 2020		55,489
Purchase of treasury stock, at cost	(38,536)	$ 0	0	38,536	0
Issuance of equity-based incentive awards and dividend equivalents	0	0	(25,085)	26,421	(1,336)
Stock-based compensation expense	25,603	0	23,439	2,164	0
Other	1,582	0	843	739	0
Dividends paid	(32,828)	0	0	0	(32,828)
Unrealized gain (loss) on marketable securities, net of tax	(7)	0	0	0	(7)
Net income	87,076	0	0	0	87,076
Balance at Jun. 30, 2021	87,262	$ 555	94,396	(635,627)	627,938
Balance (shares) at Jun. 30, 2021		55,489
Stock Issued During Period, Value, Stock Options Exercised	240	$ 0	329	569	0
Balance at Mar. 31, 2021	73,644	$ 555	81,329	(628,391)	620,151
Balance (shares) at Mar. 31, 2021		55,489
Purchase of treasury stock, at cost	(8,850)	$ 0	0	8,850	0
Stock-based compensation expense	13,781	0	12,588	1,193	0
Other	900	0	479	421	0
Dividends paid	(17,367)	0	0	0	(17,367)
Net income	25,154	0	0	0	25,154
Balance at Jun. 30, 2021	87,262	$ 555	94,396	(635,627)	627,938
Balance (shares) at Jun. 30, 2021		55,489
Balance at Dec. 31, 2021	(1,774)	$ 555	109,179	(665,089)	553,581
Balance (shares) at Dec. 31, 2021		55,489
Purchase of treasury stock, at cost	(56,805)	$ 0	0	56,805	0
Issuance of equity-based incentive awards and dividend equivalents	0	0	(9,248)	10,399	(1,151)
Stock-based compensation expense	25,477	0	24,527	950	0
Other	1,899	0	1,164	735	0
Dividends paid	(37,097)	0	0	0	(37,097)
Unrealized gain (loss) on marketable securities, net of tax	(51)	0	0	0	(51)
Net income	103,483	0	0	0	103,483
Balance at Jun. 30, 2022	35,132	$ 555	125,622	(709,810)	618,765
Balance (shares) at Jun. 30, 2022		55,489
Balance at Mar. 31, 2022	33,961	$ 555	110,053	(681,625)	604,978
Balance (shares) at Mar. 31, 2022		55,489
Purchase of treasury stock, at cost	(29,364)	$ 0	0	29,364	0
Issuance of equity-based incentive awards and dividend equivalents	0	0	(34)	34	0
Stock-based compensation expense	15,631	0	14,952	679	0
Other	1,117	0	651	466	0
Dividends paid	(19,853)	0	0	0	(19,853)
Unrealized gain (loss) on marketable securities, net of tax	41	0	0	0	41
Net income	33,599	0	0	0	33,599
Balance at Jun. 30, 2022	$ 35,132	$ 555	$ 125,622	$ (709,810)	$ 618,765
Balance (shares) at Jun. 30, 2022		55,489