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		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net realized gains (losses): [Abstract]
Net realized gains (losses) on investments	$ 4,341	$ (1,958)	$ 96,267	$ 75,519
Excluding Life Funds Withheld Assets
Net realized gains (losses): [Abstract]
Gross realized gains	37,875	22,517	208,035	160,555
Gross realized losses on investments sold	(26,918)	(21,288)	(68,662)	(74,822)
OTTI on investments, net of amounts transferred to other comprehensive income	(1,144)	(3,187)	(29,487)	(10,214)
Net realized gains (losses) on investments	9,813	(1,958)	109,886	75,519
Life Funds Withheld Assets
Net realized gains (losses): [Abstract]
Gross realized gains	4,511	0	5,135	0
Gross realized losses on investments sold	(2,489)	0	(2,489)	0
OTTI on investments, net of amounts transferred to other comprehensive income	(7,494)	0	(16,265)	0
Net realized gains (losses) on investments	$ (5,472)	$ 0	$ (13,619)	$ 0