Derivative Instruments - Components of life retrocession embedded derivative (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Derivative [Line Items]
Net realized and unrealized gains (losses) on derivative instruments	$ 16,521	$ 1,810
Life Funds Withheld Assets
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	(203,730)	0
Net adjustments related to future policy benefit reserves, net of tax	(11,954)
Net realized and unrealized gains (losses) on derivative instruments - Life Funds Withheld Assets	(13,683)	0
Net realized and unrealized gains (losses) on derivative instruments	(229,367)	0
Life Funds Withheld Assets \| Interest Income [Member]
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	(50,996)	0
Life Funds Withheld Assets \| Net realized and unrealized gains (losses) on derivative instruments
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	(152,830)	0
Life Funds Withheld Assets \| Other Income [Member]
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	96	0
Life Funds Withheld Assets \| Unrealized gains (losses) on investments
Derivative [Line Items]
Net adjustments related to future policy benefit reserves, net of tax		$ 0

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (a),(c),(d),(e)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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Net Increase or Decrease in the fair value of the embedded derivative or group of embedded derivatives included 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

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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Net Increase or Decrease in the fair value of other derivative or group of other derivatives included in earnings in the period.

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Cumulative adjustment to future policy benefit reserve, excluding foreign exchange effects.

+ References

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