Foreign Currencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Schedule of Foreign Currency Balance [Line Items]
Investment subject to foreign currency fluctuations	$ 89,350	$ 89,350
Cumulative foreign currency translation loss, net of deferred income tax benefit	(3,053)	(3,053)	(1,940)
Amount reclassified to net income