CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Common stock [Member]	Additional paid-in capital [Member]	Retained earnings (deficit) [Member]	Accumulated other comprehensive income [Member]	Total
Balance at beginning of period at Dec. 31, 2020	$ 711	$ 1,280,841	$ (1,139,139)	$ (2,155)	$ 140,258
Balance (in shares) at Dec. 31, 2020	71,123,000
Net income			501,609		501,609
Other comprehensive income				(4,143)	(4,143)
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes		4,090			4,090
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	11,000
Net issuance of common stock upon exercise of stock options	$ 1	9,844			9,845
Net issuance of common stock upon exercise of stock options, shares	76,000
Share-based compensation		5,912			5,912
Share repurchases, including fees	$ (15)	(26,654)	(637,879)		$ (664,548)
Share repurchases, including fees, shares	(1,475,000)				(1,475,000)
Balance at end of period at Mar. 31, 2021	$ 697	1,274,033	(1,275,409)	(6,298)	$ (6,977)
Balance (in shares) at Mar. 31, 2021	69,735,000
Balance at beginning of period at Dec. 31, 2021	$ 670	1,305,508	(1,365,802)	(6,799)	$ (66,423)	[1]
Balance (in shares) at Dec. 31, 2021	67,029,000				67,029,042
Net income			481,880		$ 481,880
Other comprehensive income				5,063	5,063
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes		4,882			4,882
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	8,000
Net issuance of common stock upon exercise of stock options	$ 1	15,438			15,439
Net issuance of common stock upon exercise of stock options, shares	50,000
Share-based compensation		6,094			6,094
Share repurchases, including fees	$ (12)	(22,851)	(752,345)		$ (775,208)
Share repurchases, including fees, shares	(1,167,000)				(1,167,000)
Balance at end of period at Mar. 31, 2022	$ 659	$ 1,309,071	$ (1,636,267)	$ (1,736)	$ (328,273)
Balance (in shares) at Mar. 31, 2022	65,920,000				65,919,929

[1] The balance sheet at December 31, 2021, has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by United States generally accepted accounting principles for complete financial statements.