Investments - Analysis of net realized gains (losses) and the change in unrealized (losses) gains on investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net realized gains (losses): [Abstract]
Net realized gains (losses) on investments	$ 72,697	$ 40,968	$ 91,926	$ 77,477
Excluding Life Funds Withheld Assets
Net realized gains (losses): [Abstract]
Gross realized gains	118,947	64,865	170,160	138,038
Gross realized losses on investments sold	(13,487)	(21,508)	(41,744)	(53,534)
OTTI on investments, net of amounts transferred to other comprehensive income	(24,616)	(2,389)	(28,343)	(7,027)
Net realized gains (losses) on investments	80,844	40,968	100,073	77,477
Life Funds Withheld Assets
Net realized gains (losses): [Abstract]
Gross realized gains	624	0	624	0
Gross realized losses on investments sold	0	0	0	0
OTTI on investments, net of amounts transferred to other comprehensive income	(8,771)	0	(8,771)	0
Net realized gains (losses) on investments	$ (8,147)	$ 0	$ (8,147)	$ 0