CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2018	$ 77,676	$ 555	$ 36,752	$ (357,569)	$ (9)	$ 397,947
Balance (shares) at Dec. 31, 2018		55,489
Purchase of treasury stock, at cost	(203,043)	$ 0	0	(203,043)	0	0
Stock Issued During Period, Value, Share-based Compensation, Gross	0	0	(7,695)	8,646	0	(951)
Stock-based compensation expense	23,993	0	16,899	7,094	0	0
Other	2,955	0	2,185	770	0	0
Dividends paid	(48,622)	0	0	0	0	(48,622)
Unrealized gain (loss) on marketable securities, net of tax	21	0	0	0	21	0
Net income	151,099	0	0	0	0	151,099
Balance at Dec. 31, 2019	4,079	$ 555	48,141	(544,102)	12	499,473
Balance (shares) at Dec. 31, 2019		55,489
Purchase of treasury stock, at cost	(99,415)	$ 0	0	(99,415)	0	0
Stock Issued During Period, Value, Share-based Compensation, Gross	0	0	(7,140)	7,953	0	(813)
Stock-based compensation expense	60,145	0	53,561	6,584	0	0
Other	2,962	0	966	1,996	0	0
Dividends paid	(61,869)	0	0	0	0	(61,869)
Unrealized gain (loss) on marketable securities, net of tax	(7)	0	0	0	(7)	0
Net income	138,237	0	0	0	0	138,237
Balance at Dec. 31, 2020	44,132	$ 555	95,528	(626,984)	5	575,028
Balance (shares) at Dec. 31, 2020		55,489
Purchase of treasury stock, at cost	(69,725)	$ 0	0	(69,725)	0	0
Stock Issued During Period, Value, Share-based Compensation, Gross	0	0	(25,140)	26,479	0	(1,339)
Stock-based compensation expense	40,623	0	37,381	3,242	0	0
Stock Issued During Period, Value, Stock Options Exercised	240	0	(329)	569	0	0
Other	3,069	0	1,739	1,330	0	0
Dividends paid	(144,179)	0	0	0	0	(144,179)
Unrealized gain (loss) on marketable securities, net of tax	(14)	0	0	0	(14)	0
Net income	124,080	0	0	0	0	124,080
Balance at Dec. 31, 2021	$ (1,774)	$ 555	$ 109,179	$ (665,089)	$ (9)	$ 553,590
Balance (shares) at Dec. 31, 2021		55,489