Summary of Total Revenues Attributed to Geographic Sources (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 246,919	$ 196,237
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	214,956	176,911
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	24,343	14,362
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 7,620	$ 4,964