Summary of Total Revenues Attributed to Geographic Sources (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 291,230	$ 208,252	$ 538,149	$ 404,489
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	247,525	191,274	462,481	368,185
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	30,687	13,074	55,030	27,436
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 13,018	$ 3,904	$ 20,638	$ 8,868