Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (shares) at Dec. 31, 2018		255,172
Beginning balance at Dec. 31, 2018	$ 4,435,203	$ 2,546	$ 7,421,476	$ 659	$ (2,989,478)
Increase (Decrease) in Stockholders' Equity
Other comprehensive income, net of tax	5,341			5,341
Net income	268,631				268,631
Repurchases of common stock (in shares)		(537)
Repurchase of common stock	(98,007)	$ (6)	(98,001)
Common stock withheld for employee tax obligations (shares)		(27)
Common stock withheld for employee tax obligations	(5,832)		(5,832)
Issuance of common stock under benefit plans (shares)		1,743
Issuance of common stock under benefit plans	64,044	$ 21	64,023
Stock-based compensation expense	94,243		94,243
Ending balance (shares) at Mar. 31, 2019		256,351
Ending Balance at Mar. 31, 2019	4,723,313	$ 2,561	7,475,909	6,000	(2,761,157)
Beginning balance (shares) at Dec. 31, 2019		258,993
Beginning balance at Dec. 31, 2019	6,085,244	$ 2,589	7,937,606	(1,973)	(1,852,978)
Increase (Decrease) in Stockholders' Equity
Other comprehensive income, net of tax	15,356			15,356
Net income	602,753				602,753
Repurchases of common stock (in shares)		(1,404)
Repurchase of common stock	(300,026)	$ (14)	(300,012)
Common stock withheld for employee tax obligations (shares)		(575)
Common stock withheld for employee tax obligations	(136,167)	$ (6)	(136,161)
Issuance of common stock under benefit plans (shares)		2,065
Issuance of common stock under benefit plans	77,594	$ 22	77,572
Stock-based compensation expense	116,900		116,900
Ending balance (shares) at Mar. 31, 2020		259,079
Ending Balance at Mar. 31, 2020	$ 6,461,654	$ 2,591	$ 7,695,905	$ 13,383	$ (1,250,225)