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 (loss) [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			1,645,712		1,645,712
Other comprehensive income				(5,673)	(5,673)
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes	$ 1	14,152			14,153
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	32,000
Net issuance of common stock upon exercise of stock options	$ 3	54,488			54,491
Net issuance of common stock upon exercise of stock options, shares	331,000
Share-based compensation		17,367			17,367
Share repurchases, including fees	$ (38)	(70,490)	(1,936,633)		$ (2,007,161)
Share repurchases, including fees, shares	(3,801,000)				(3,801,000)
Balance at end of period at Sep. 30, 2021	$ 677	1,296,358	(1,430,060)	(7,828)	$ (140,853)
Balance (in shares) at Sep. 30, 2021	67,685,000
Balance at beginning of period at Jun. 30, 2021	$ 691	1,295,363	(1,075,769)	(2,591)	217,694
Balance (in shares) at Jun. 30, 2021	69,133,000
Net income			558,652		558,652
Other comprehensive income				(5,237)	(5,237)
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes	$ 1	4,722			4,723
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	10,000
Net issuance of common stock upon exercise of stock options	$ 1	20,718			20,719
Net issuance of common stock upon exercise of stock options, shares	125,000
Share-based compensation		5,568			5,568
Share repurchases, including fees	$ (16)	(30,013)	(912,943)		$ (942,972)
Share repurchases, including fees, shares	(1,583,000)				(1,583,000)
Balance at end of period at Sep. 30, 2021	$ 677	1,296,358	(1,430,060)	(7,828)	$ (140,853)
Balance (in shares) at Sep. 30, 2021	67,685,000
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			1,644,078		$ 1,644,078
Other comprehensive income				2,816	2,816
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes		15,272			15,272
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	26,000
Net issuance of common stock upon exercise of stock options	$ 2	42,786			42,788
Net issuance of common stock upon exercise of stock options, shares	169,000
Share-based compensation		17,563			17,563
Share repurchases, including fees	$ (44)	(88,404)	(2,773,109)		$ (2,861,557)
Share repurchases, including fees, shares	(4,425,000)				(4,425,000)
Balance at end of period at Sep. 30, 2022	$ 628	1,292,725	(2,494,833)	(3,983)	$ (1,205,463)
Balance (in shares) at Sep. 30, 2022	62,799,000				62,798,821
Balance at beginning of period at Jun. 30, 2022	$ 638	1,286,651	(2,391,108)	(3,611)	$ (1,107,430)
Balance (in shares) at Jun. 30, 2022	63,753,000
Net income			585,438		585,438
Other comprehensive income				(372)	(372)
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes		4,698			4,698
Issuance of common stock under employee benefit plans, net of forfeitures and shares withheld to cover taxes, shares	7,000
Net issuance of common stock upon exercise of stock options	$ 1	16,765			16,766
Net issuance of common stock upon exercise of stock options, shares	78,000
Share-based compensation		5,752			5,752
Share repurchases, including fees	$ (11)	(21,141)	(689,163)		$ (710,315)
Share repurchases, including fees, shares	(1,039,000)				(1,039,000)
Balance at end of period at Sep. 30, 2022	$ 628	$ 1,292,725	$ (2,494,833)	$ (3,983)	$ (1,205,463)
Balance (in shares) at Sep. 30, 2022	62,799,000				62,798,821

[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.