Foreign Currencies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Schedule of Foreign Currency Balance [Line Items]
Investment subject to foreign currency fluctuations	$ 25,031,000		$ 25,031,000
Cumulative foreign currency translation loss, net of deferred income tax benefit	(26,694,000)		(26,694,000)		$ (22,969,000)
Amount reclassified to net income			0
Income tax (benefit) expense	$ (5,387,000)	$ 5,312,000	(27,346,000)	$ 25,680,000
Foreign Currency Exchange Loss, Net
Schedule of Foreign Currency Balance [Line Items]
Income tax (benefit) expense			$ 0