Components of Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Comprehensive Income (Loss) [Line Items]
Net income (loss)	$ 36,597	$ 30,443	$ (37,838)	$ 14,657
Other comprehensive income (loss):
Foreign currency translation adjustment	911	(67)	327	(34)
Comprehensive income (loss)	$ 37,508	$ 30,376	$ (37,511)	$ 14,623