Foreign Currencies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Schedule of Foreign Currency Balance [Line Items]
Investment subject to foreign currency fluctuations	$ 34,285,000		$ 34,285,000
Cumulative foreign currency translation loss, net of deferred income tax benefit	(22,406,000)		(22,406,000)		$ (22,969,000)
Amount reclassified to net income			0
Income taxes	$ (7,917,000)	$ 11,292,000	(21,959,000)	$ 20,368,000
Foreign Currency Exchange Loss, Net
Schedule of Foreign Currency Balance [Line Items]
Income taxes			$ 0