Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period				$ (66,698)
Other comprehensive income (loss)		$ (67,146)	$ (58,038)	56,824	$ (155,545)
Accumulated Other Comprehensive Income (Loss), End of Period		(9,808)		(9,808)
Net realized investment gains		175,738	66,419	207,508	113,020
Income before income taxes		331,615	228,920	664,605	575,824
Income before taxes		606,348	573,541	1,770,450	1,698,169
Tax effect		(110,952)	(76,184)	(214,789)	(181,595)
After-tax amounts reclassified		220,663	152,736	449,816	394,229
Unrealized investment gains, pre-tax		(72,188)	(7,731)	198,808	(135,186)
Unrealized investment gains, tax effect		24,512	12,228	(64,595)	56,354
Unrealized investment gains, after-tax amounts		(47,676)	4,497	134,213	(78,832)
Currency translation adjustment, pre-tax		(19,470)	(62,535)	(77,389)	(76,713)
Currency translation adjustment, tax effect		0	0	0
Change in unrealized currency translation adjustments		(19,470)	(62,535)	(77,389)	(76,713)
Other comprehensive income (loss), pre-tax		(91,658)	(70,266)	121,419	(211,899)
Other comprehensive income (loss), tax effect		24,512	12,228	(64,595)	56,354
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		362,593	222,882	180,695	306,199
Other comprehensive income (loss) before reclassifications		(20,968)	3,943	170,824	(69,078)
Amounts reclassified from AOCI		(26,708)	554	(36,611)	(9,754)
Other comprehensive income (loss)		(47,676)	4,497	134,213	(78,832)
Unrealized investment gain related to non-controlling interest		57	94	66	106
Accumulated Other Comprehensive Income (Loss), End of Period		314,974	227,473	314,974	227,473
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		(305,312)	(136,827)	(247,393)	(122,649)
Other comprehensive income (loss) before reclassifications		(19,470)	(62,535)	(77,389)	(76,713)
Amounts reclassified from AOCI		0	0	0	0
Other comprehensive income (loss)		(19,470)	(62,535)	(77,389)	(76,713)
Unrealized investment gain related to non-controlling interest		0	0	0	0
Accumulated Other Comprehensive Income (Loss), End of Period		(324,782)	(199,362)	(324,782)	(199,362)
Change in unrealized currency translation adjustments				(77,389)	(76,713)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		57,281	86,055	(66,698)	183,550
Other comprehensive income (loss) before reclassifications		(40,438)	(58,592)	93,435	(145,791)
Amounts reclassified from AOCI		(26,708)	554	(36,611)	(9,754)
Other comprehensive income (loss)		(67,146)	(58,038)	56,824	(155,545)
Unrealized investment gain related to non-controlling interest		57	94	66	106
Accumulated Other Comprehensive Income (Loss), End of Period		(9,808)	28,111	(9,808)	28,111
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net realized investment gains	[1]	(41,090)	852	(56,325)	(15,006)
Tax effect	[2]	(14,382)	298	(19,714)	(5,252)
After-tax amounts reclassified		(26,708)	554	(36,611)	(9,754)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before income taxes		0	0	0	0
Tax effect		0	0	0	0
After-tax amounts reclassified		0	0	0	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before income taxes		(41,090)	852	(56,325)	(15,006)
Tax effect		14,382	(298)	19,714	5,252
After-tax amounts reclassified		$ (26,708)	$ 554	$ (36,611)	$ (9,754)

[1] Net investment (gains) losses in the consolidated statements of income.

[2] Income tax expense in the consolidated statements of income.