Derivative Instruments - Hedged items - amount of gain/(loss) recognized in income attributable to risk (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments Gain Loss [Line Items]
Ineffective portion of hedging relationship - gain/(loss)	$ 0	$ 0	$ (256)
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	0	(15,663)
Ineffective portion of hedging relationship - gain/(loss)	0	0	(256)
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Fixed maturities
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	0	15,407
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Interest Rate Contract [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	0	0
Designated as Hedging Instrument \| Fair Value Hedging Member \| Net realized and unrealized gains (losses) on derivative instruments [Member] \| Foreign Exchange Exposure
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 0	$ 0	$ (15,663)

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.

No definition available.

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Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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