Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenues	$ 2,984,859	$ 2,290,188	$ 8,406,958	$ 6,353,128
Cost of revenues	1,992,980	1,532,844	5,552,312	4,375,482
Marketing	312,490	282,043	858,083	706,082
Technology and development	255,236	216,099	779,427	626,907
General and administrative	215,526	153,166	623,760	418,798
Operating income	208,627	106,036	593,376	225,859
Other income (expense):
Interest expense	(60,688)	(35,536)	(162,912)	(106,528)
Interest and other income (expense)	(31,702)	8,627	(76,473)	50,907
Income before income taxes	116,237	79,127	353,991	170,238
Provision for (benefit from) income taxes	(13,353)	27,610	(19,421)	50,308
Net income	$ 129,590	$ 51,517	$ 373,412	$ 119,930
Earnings per share:
Basic (in dollars per share)	$ 0.30	$ 0.12	$ 0.87	$ 0.28
Diluted (in dollars per share)	$ 0.29	$ 0.12	$ 0.84	$ 0.27
Weighted-average common shares outstanding:
Basic (in shares)	432,404	428,937	431,473	428,514
Diluted (in shares)	447,362	438,389	446,367	438,180