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

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
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-SubTopic 10
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-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611

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- Definition

The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

+ References

No definition available.

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- Definition

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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No definition available.

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- Definition

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
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The cash inflow provided by derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments.

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No definition available.

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Derivative Instruments (Narrative) (Details) $ in Thousands, £ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 GBP (£) instrument	Jul. 01, 2016 instrument	Jun. 30, 2016 USD ($)
Derivative [Line Items]
Gain (loss) to be reclassified within twelve months	$ 6,600
Proceeds from forward contracts	0	$ 51,308
Designated as Hedging Instrument \| Currency forward contracts
Derivative [Line Items]
Number of Instruments \| instrument			4	4
Notional amount \| £			£ 357.3
Proceeds from forward contracts	64,000
Amount of AOCI to remain in AOCI	$ 26,200
Not Designated as Hedging Instrument \| Currency forward contracts
Derivative [Line Items]
Fair value of derivatives					$ 37,800