Foreign Currency Translation - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Foreign Currency [Abstract]
Accumulated other comprehensive income (loss)	$ 309,306	$ 253,282
Cumulative foreign currency adjustments	$ 309,609	$ 253,565
Cumulative inflation rate	100.00%
Cumulative inflation period	3 years

Accumulated adjustment, net of tax, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains or losses.

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Name:	us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant