Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenues	$ 2,290,188	$ 1,738,355	$ 6,353,128	$ 4,956,178
Cost of revenues	1,532,844	1,173,958	4,375,482	3,342,111
Marketing	282,043	208,102	706,082	599,919
Technology and development	216,099	171,762	626,907	469,929
General and administrative	153,166	110,892	418,798	298,287
Operating income	106,036	73,641	225,859	245,932
Other income (expense):
Interest expense	(35,536)	(35,333)	(106,528)	(97,287)
Interest and other income (expense)	8,627	3,930	50,907	(27,491)
Income before income taxes	79,127	42,238	170,238	121,154
Provision for income taxes	27,610	12,806	50,308	41,691
Net income	$ 51,517	$ 29,432	$ 119,930	$ 79,463
Earnings per share:
Basic (in dollars per share)	$ 0.12	$ 0.07	$ 0.28	$ 0.19
Diluted (in dollars per share)	$ 0.12	$ 0.07	$ 0.27	$ 0.18
Weighted-average common shares outstanding:
Basic (in shares)	428,937	426,869	428,514	425,289
Diluted (in shares)	438,389	437,606	438,180	435,849