Investments - Analysis of net realized gains (losses) and the change in unrealized (losses) gains on investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net realized gains (losses): [Abstract]
Net realized gains (losses) on investments	$ 51,407	$ 4,341	$ 154,265	$ 96,267
Excluding Life Funds Withheld Assets
Net realized gains (losses): [Abstract]
Gross realized gains	88,224	37,875	199,070	208,035
Gross realized losses on investments sold	(45,711)	(26,918)	(120,440)	(68,662)
OTTI on investments, net of amounts transferred to other comprehensive income	(42,714)	(1,144)	(69,878)	(29,487)
Net realized gains (losses) on investments	(201)	9,813	8,752	109,886
Life Funds Withheld Assets
Net realized gains (losses): [Abstract]
Gross realized gains	60,643	4,511	198,412	5,135
Gross realized losses on investments sold	(6,863)	(2,489)	(23,857)	(2,489)
OTTI on investments, net of amounts transferred to other comprehensive income	(2,023)	(7,494)	(10,110)	(16,265)
Net unrealized gains (losses) on investments, trading securities	(149)	0	(18,932)	0
Net realized gains (losses) on investments	$ 51,608	$ (5,472)	$ 145,513	$ (13,619)