Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues	$ 2,636,635	$ 1,957,736
Cost of revenues	1,657,024	1,369,540
Marketing	271,270	208,010
Technology and development	257,108	203,508
General and administrative	194,291	127,225
Operating income	256,942	49,453
Other income (expense):
Interest expense	(46,742)	(35,537)
Interest and other income (expense)	13,592	25,963
Income before income taxes	223,792	39,879
Provision for income taxes	45,570	12,221
Net income	$ 178,222	$ 27,658
Earnings per share:
Basic (in dollars per share)	$ 0.41	$ 0.06
Diluted (in dollars per share)	$ 0.40	$ 0.06
Weighted-average common shares outstanding:
Basic (in shares)	430,600	428,117
Diluted (in shares)	445,458	437,993