Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

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+ References

No definition available.

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- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

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Derivative Financial Instruments - Summary of Non-designated Hedges (Detail) € in Thousands, £ in Thousands, $ in Thousands, $ in Thousands	Jun. 30, 2019 AUD ($) DerivativeInstrument	Jun. 30, 2019 CAD ($) DerivativeInstrument	Jun. 30, 2019 EUR (€) DerivativeInstrument	Dec. 31, 2018 AUD ($) DerivativeInstrument	Dec. 31, 2018 EUR (€) DerivativeInstrument	Dec. 31, 2018 GBP (£) DerivativeInstrument
AUD [Member] \| Buy AUD / Sell USD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount \| $				$ 55,000
AUD [Member] \| Buy USD / Sell AUD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount \| $				$ 55,000
EUR [Member] \| Buy GBP / Sell EUR Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount \| €			€ 12,857
Not Designated as Hedging Instrument [Member] \| AUD [Member] \| Buy AUD / Sell USD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments	1	1	1	1	1	1
Notional Amount \| $	$ 99,000
Not Designated as Hedging Instrument [Member] \| AUD [Member] \| Buy USD / Sell AUD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments	1	1	1	1	1	1
Notional Amount \| $	$ 99,000
Not Designated as Hedging Instrument [Member] \| GBP [Member] \| Buy GBP / Sell USD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments				1	1	1
Notional Amount \| £						£ 23,200
Not Designated as Hedging Instrument [Member] \| GBP [Member] \| Buy USD / Sell GBP Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments				1	1	1
Notional Amount \| £						£ 23,200
Not Designated as Hedging Instrument [Member] \| EUR [Member] \| Buy GBP / Sell EUR Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments	1	1	1	1	1	1
Notional Amount \| €					€ 12,857
Not Designated as Hedging Instrument [Member] \| CAD [Member] \| Buy USD / Sell CAD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments	3	3	3
Notional Amount \| $		$ 19,400
Not Designated as Hedging Instrument [Member] \| CAD [Member] \| Buy CAD / Sell USD Forward [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Instruments	3	3	3
Notional Amount \| $		$ 19,400