Segment and Geographic Information - Narrative (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 segment	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of operating segments (in number of segments)									1
Property and equipment, net	$ 601,591				$ 450,287				$ 601,591	$ 450,287
Revenue	536,295	498,042	476,035	453,502	435,980	395,790	378,106	368,046	1,963,874	1,577,922	1,373,947
United States
Segment Reporting Information [Line Items]
Property and equipment, net	249,500				210,900				249,500	210,900
Foreign locations
Segment Reporting Information [Line Items]
Property and equipment, net	175,800				124,900				175,800	124,900
Revenue									$ 531,900	$ 432,600	$ 369,000
Sales | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Concentration risk, number of foreign countries (in number of countries)									0		0
Concentration risk, percentage (in percentage)									10.00%		10.00%