Derivatives and Hedging Activity - Designated and Non-Designated Hedges (Details) - 9 months ended Sep. 30, 2017 € in Thousands, £ in Thousands, $ in Thousands	GBP (£) instrument item	USD ($) instrument item	EUR (€) instrument item
Derivatives
Number of contracts	223	223	223
Foreign exchange contracts \| EUR \| Sell
Derivatives
Number of contracts	44	44	44
Aggregate notional amount \| €			€ 283,394
Foreign exchange contracts \| EUR \| Sell \| Ireland Portfolio
Derivatives
Number of contracts	33	33	33
Aggregate notional amount \| €			€ 231,100
Foreign exchange contracts \| GBP \| Sell
Derivatives
Number of contracts	129	129	129
Aggregate notional amount \| £	£ 263,925
Interest rate swaps \| Derivatives designated as hedging instruments
Derivatives
Number of contracts \| instrument	4	4	4
Aggregate notional amount \| $		$ 40,000
Hedging period for covering exposure to the variability in future cash flows	44 months
Interest rate swaps \| Derivatives designated as hedging instruments \| Minimum
Derivatives
Fixed monthly coupons at fixed rate (as a percent)	0.64%	0.64%	0.64%
Interest rate swaps \| Derivatives designated as hedging instruments \| Maximum
Derivatives
Fixed monthly coupons at fixed rate (as a percent)	1.52%	1.52%	1.52%
Interest rate swaps - Paying fixed rates \| USD
Derivatives
Number of contracts	30	30	30
Aggregate notional amount \| $		$ 815,730
Interest rate caps \| EUR
Derivatives
Number of contracts	2	2	2
Aggregate notional amount \| €			€ 294,000
Interest rate caps \| USD
Derivatives
Number of contracts	8	8	8
Aggregate notional amount \| $		$ 68,194
Credit index instruments \| USD
Derivatives
Number of contracts	10	10	10
Aggregate notional amount \| $		$ 59,000

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

Fixed interest rate related to the interest rate derivative.

+ 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.

+ 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579245-113959

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- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ 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 (d)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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