Derivative Instruments - Components of life retrocession embedded derivative (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative [Line Items]
Net realized and unrealized gains (losses) on derivative instruments	$ 5,131	$ 880	$ 18,540	$ 3,660
Life Funds Withheld Assets
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	(172,077)	0	(189,623)	0
Net adjustments related to future policy benefit reserves, net of tax	(18,376)		(18,376)
Net realized and unrealized gains (losses) on derivative instruments - Life Funds Withheld Assets	(10,811)	0	(10,811)	0
Net realized and unrealized gains (losses) on derivative instruments	(201,264)	0	(218,810)	0
Life Funds Withheld Assets | Interest Income [Member]
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	(59,424)	0	(79,368)	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	(113,916)	0	(112,023)	0
Life Funds Withheld Assets | Other Income [Member]
Derivative [Line Items]
Net realized and unrealized gains (losses) on life retrocession embedded derivative	1,263	0	1,768	0
Life Funds Withheld Assets | Unrealized gains (losses) on investments
Derivative [Line Items]
Net adjustments related to future policy benefit reserves, net of tax	$ (18,376)	$ 0	$ (18,376)	$ 0