Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Revenues	$ 4,374,562	$ 3,609,282	$ 3,204,577
Cost of revenues	3,083,256	2,625,866	2,039,901
Marketing	503,889	465,400	381,269
Technology and development	378,769	329,008	259,033
General and administrative	180,301	139,016	148,306
Operating income	228,347	49,992	376,068
Other income (expense):
Interest expense	(29,142)	(19,986)	(20,025)
Interest and other income (expense)	(3,002)	474	3,479
Loss on extinguishment of debt	(25,129)	0	0
Income before income taxes	171,074	30,480	359,522
Provision for income taxes	58,671	13,328	133,396
Net income	$ 112,403	$ 17,152	$ 226,126
Earnings per share:
Basic (in dollars per share)	$ 1.93	$ 0.31	$ 4.28
Diluted (in dollars per share)	$ 1.85	$ 0.29	$ 4.16
Weighted-average common shares outstanding:
Basic (in shares)	58,198	55,521	52,847
Diluted (in shares)	60,761	58,904	54,369