Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenues	$ 2,785,464	$ 2,105,204	$ 5,422,099	$ 4,062,940
Cost of revenues	1,902,308	1,473,098	3,559,332	2,842,638
Marketing	274,323	216,029	545,593	424,039
Technology and development	267,083	207,300	524,191	410,808
General and administrative	213,943	138,407	408,234	265,632
Operating income	127,807	70,370	384,749	119,823
Other income (expense):
Interest expense	(55,482)	(35,455)	(102,224)	(70,992)
Interest and other income (expense)	(58,363)	16,317	(44,771)	42,280
Income before income taxes	13,962	51,232	237,754	91,111
Provision for (benefit from) income taxes	(51,638)	10,477	(6,068)	22,698
Net income	$ 65,600	$ 40,755	$ 243,822	$ 68,413
Earnings per share:
Basic (in dollars per share)	$ 0.15	$ 0.10	$ 0.57	$ 0.16
Diluted (in dollars per share)	$ 0.15	$ 0.09	$ 0.55	$ 0.16
Weighted-average common shares outstanding:
Basic (in shares)	431,396	428,483	431,000	428,300
Diluted (in shares)	446,262	438,154	445,862	438,073