Consolidated Statements of Shareholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2018	$ (166,494)		$ 1,300	$ (3,272,774)	$ 1,306,428	$ 1,856,951		$ (58,399)
Net income	563,648					563,648
Dividends declared	(221,075)				230	(221,305)
Other comprehensive income (loss), net of tax	(4,180)							(4,180)
Shares withheld for tax withholding and exercises	(189,994)			(189,994)
Common stock issued	23		23
Compensation payable in common stock and options	41,138				41,138
Common stock repurchased and held in treasury	(102,081)			(102,081)
Common stock issued to Directors and (held in)/released from treasury	(935)			(935)
Exercise of stock options	3,236		1		3,235
Balance at Dec. 31, 2019	(76,714)		1,324	(3,565,784)	1,351,031	2,199,294		(62,579)
Net income	601,822					601,822
Dividends declared	(247,452)					(247,452)
Dividends paid in shares	186				186
Other comprehensive income (loss), net of tax	3,720							3,720
Shares withheld for tax withholding and exercises	(51,176)			(51,176)
Common stock issued	4		4
Compensation payable in common stock and options	51,320				51,320
Common stock repurchased and held in treasury	(727,343)			(727,343)
Common stock issued to Directors and (held in)/released from treasury	1,768			1,768
Balance at Dec. 31, 2020	(443,234)	$ 631	1,328	(4,342,535)	1,402,537	2,554,295	$ 631	(58,859)
Net income	725,983					725,983
Dividends declared	(303,761)					(303,761)
Dividends paid in shares	128				128
Other comprehensive income (loss), net of tax	64							64
Shares withheld for tax withholding and exercises	(58,794)			(58,794)
Common stock issued	4		4
Compensation payable in common stock and options	54,958				54,958
Common stock repurchased and held in treasury	(139,580)			(139,580)
Common stock issued to Directors and (held in)/released from treasury	765			765
Balance at Dec. 31, 2021	$ (163,467)		$ 1,332	$ (4,540,144)	$ 1,457,623	$ 2,976,517		$ (58,795)