Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period				$ 183,550
Other comprehensive income (loss)		$ (65,993)	$ 75,035	(97,507)	$ 144,545
Accumulated Other Comprehensive Income (Loss), End of Period		86,055		86,055
Net realized investment gains		27,557	109,168	46,601	161,922
Income before income taxes		178,187	263,454	346,904	511,039
Income before taxes		573,582	534,150	1,124,628	1,049,316
Tax effect		55,138	83,277	105,411	161,178
After-tax amounts reclassified		123,049	180,177	241,493	349,861
Unrealized investment gains, pre-tax		(151,991)	76,390	(127,455)	188,680
Unrealized investment gains, tax effect		52,371	(28,190)	44,126	(67,536)
Unrealized investment gains, after-tax amounts		(99,620)	48,200	(83,329)	121,144
Currency translation adjustment, pre-tax		33,627	24,815	(14,178)	20,790
Currency translation adjustment, tax effect		0	0	0	0
Change in unrealized currency translation adjustments		33,627	24,815	(14,178)	20,790
Net pension asset, pre-tax		0	3,108	0	4,017
Net pension asset, tax effect		0	(1,088)	0	(1,406)
Net pension asset, after-tax amounts		0	2,020	0	2,611
Other comprehensive income (loss), pre-tax		(118,364)	104,313	(141,633)	213,487
Other comprehensive income (loss), tax effect		52,371	(29,278)	44,126	(68,942)
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		322,512	329,492	306,199	256,566
Other comprehensive income (loss) before reclassifications		(97,613)	62,846	(73,021)	140,289
Amounts reclassified from AOCI		(2,007)	(14,646)	(10,308)	(19,145)
Other comprehensive income (loss)		(99,620)	48,200	(83,329)	121,144
Unrealized investment gain related to non-controlling interest		(10)	(19)	12	(37)
Accumulated Other Comprehensive Income (Loss), End of Period		222,882	377,673	222,882	377,673
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		(170,454)	(64,549)	(122,649)	(60,524)
Other comprehensive income (loss) before reclassifications		33,627	24,815	(14,178)	20,790
Amounts reclassified from AOCI		0	0	0	0
Other comprehensive income (loss)		33,627	24,815	(14,178)	20,790
Unrealized investment gain related to non-controlling interest		0	0	0	0
Accumulated Other Comprehensive Income (Loss), End of Period		(136,827)	(39,734)	(136,827)	(39,734)
Change in unrealized currency translation adjustments				(14,178)	20,790
Net Pension Asset [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		0	(6,060)	0	(6,651)
Other comprehensive income (loss) before reclassifications		0	0	0	0
Amounts reclassified from AOCI		0	2,020	0	2,611
Other comprehensive income (loss)		0	2,020	0	2,611
Unrealized investment gain related to non-controlling interest		0	0	0	0
Accumulated Other Comprehensive Income (Loss), End of Period		0	(4,040)	0	(4,040)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period		152,058	258,883	183,550	189,391
Other comprehensive income (loss) before reclassifications		(63,986)	87,661	(87,199)	161,079
Amounts reclassified from AOCI		(2,007)	(12,626)	(10,308)	(16,534)
Other comprehensive income (loss)		(65,993)	75,035	(97,507)	144,545
Unrealized investment gain related to non-controlling interest		(10)	(19)	12	(37)
Accumulated Other Comprehensive Income (Loss), End of Period		86,055	333,899	86,055	333,899
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]	(3,087)	(22,532)	(15,858)	(29,454)
Tax effect	[2]	1,080	7,886	5,550	10,309
After-tax amounts reclassified		(2,007)	(14,646)	(10,308)	(19,145)
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	[2]	0	0	0	0
After-tax amounts reclassified		0	0	0	0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Pension Asset [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before taxes	[3]	0	3,108	0	4,017
Tax effect	[2]	0	(1,088)	0	(1,406)
After-tax amounts reclassified		0	2,020	0	2,611
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		(3,087)	(19,424)	(15,858)	(25,437)
Tax effect	[2]	(1,080)	(6,798)	(5,550)	(8,903)
After-tax amounts reclassified		$ (2,007)	$ (12,626)	$ (10,308)	$ (16,534)

[1] Net investment gains in the consolidated statements of

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