Segment and Other Information - Summary of Total Revenues Attributed to Geographic Sources (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 340,872	$ 306,584	$ 983,922	$ 844,733
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	305,585	264,719	877,397	727,200
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	26,076	32,578	82,837	87,608
All Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 9,211	$ 9,287	$ 23,688	$ 29,925