Derivative Financial Instruments - Summary of Effect of Derivative Financial Instruments on Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of (Loss) Gain Recognized in OCI on Derivatives	$ (21,459)	$ 25,444	$ 23,882
Amount of Loss Reclassified from Accumulated OCI into Income	(831)	(798)	(4)
Net Investment [Member] \| Foreign Currency Contracts [Member] \| Interest Expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of (Loss) Gain Recognized in OCI on Derivatives	(22,216)	25,355	25,356
Cash Flow Hedges [Member] \| Interest Rate Swaps/Derivatives [Member] \| Interest Expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of (Loss) Gain Recognized in OCI on Derivatives	757	89	(1,474)
Amount of Loss Reclassified from Accumulated OCI into Income	$ (831)	$ (798)	$ (4)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

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