Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenues	$ 3,907,270	$ 2,785,464	$ 7,608,126	$ 5,422,099
Cost of revenues	2,289,867	1,902,308	4,485,942	3,559,332
Marketing	526,780	274,323	1,006,002	545,593
Technology and development	317,213	267,083	617,943	524,191
General and administrative	311,197	213,943	589,448	408,234
Operating income	462,213	127,807	908,791	384,749
Other income (expense):
Interest expense	(101,605)	(55,482)	(182,824)	(102,224)
Interest and other income (expense)	68,028	(58,363)	2,285	(44,771)
Income before income taxes	428,636	13,962	728,252	237,754
Provision for (benefit from) income taxes	44,287	(51,638)	53,779	(6,068)
Net income	$ 384,349	$ 65,600	$ 674,473	$ 243,822
Earnings per share:
Basic (in dollars per share)	$ 0.88	$ 0.15	$ 1.55	$ 0.57
Diluted (in dollars per share)	$ 0.85	$ 0.15	$ 1.50	$ 0.55
Weighted-average common shares outstanding:
Basic (in shares)	435,097	431,396	434,638	431,000
Diluted (in shares)	451,552	446,262	450,958	445,862