Statements of Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2013	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]	Sep. 30, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]	Mar. 31, 2013 Accumulated Net Unrealized Investment Gain (Loss) [Member]	Sep. 30, 2013 Currency Translation Adjustments [Member]	Sep. 30, 2013 Currency Translation Adjustments [Member]	Sep. 30, 2012 Currency Translation Adjustments [Member]	Mar. 31, 2013 Currency Translation Adjustments [Member]	Sep. 30, 2013 Net Pension Asset [Member]	Sep. 30, 2013 Net Pension Asset [Member]	Mar. 31, 2013 Net Pension Asset [Member]	Sep. 30, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Sep. 30, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Mar. 31, 2013 Accumulated Other Comprehensive Income (Loss) [Member]	Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Accumulated Net Unrealized Investment Gain (Loss) [Member]		Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Accumulated Net Unrealized Investment Gain (Loss) [Member]		Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Currency Translation Adjustments [Member]	Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Currency Translation Adjustments [Member]	Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Net Pension Asset [Member]		Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Net Pension Asset [Member]		Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Member]	Sep. 30, 2013 Reclassification out of Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period			$ 465,631			$ 517,658	$ 328,403		$ (36,676)		$ (106,455)		$ (15,351)	$ (11,723)		$ 465,631	$ 210,225
Other comprehensive income (loss) before reclassifications					(10,331)	(172,276)		44,328	(25,451)			0	0		33,997	(197,727)
Amounts reclassified from AOCI					(28,548)	(55,853)		0	0			1,814	5,442		(26,734)	(50,411)
Other comprehensive income (loss)	7,263	91,840	(248,138)	153,372	(38,879)	(228,129)		44,328	(25,451)			1,814	5,442		7,263	(248,138)
Unrealized investment gain related to non-controlling interest					(9)	(14)									(9)	(14)
Accumulated Other Comprehensive Income (Loss), End of Period	217,479		217,479		289,515	289,515	328,403	(62,127)	(62,127)		(106,455)	(9,909)	(9,909)	(11,723)	217,479	217,479	210,225
Net investment gains	43,869	17,226	96,896	84,989														(43,920)	[1]	(85,928)	[1]
Income before income taxes	198,233	133,693	517,162	469,435																		0	0					(41,130)	(77,556)
Income before taxes	504,096	451,487	1,479,986	1,332,024																				2,790	[2]	8,372	[2]
Tax effect	(60,045)	(32,685)	(147,249)	(124,291)														15,372	[3]	30,075	[3]	0	0	(976)	[3]	(2,930)	[3]	14,396	27,145
After-tax amounts reclassified	138,188	101,008	369,913	345,144														(28,548)		(55,853)		0	0	1,814		5,442		(26,734)	(50,411)
Unrealized investment gains, pre-tax	(59,814)		(350,968)
Unrealized investment gains, tax effect	20,935		122,839
Unrealized investment gains, after-tax amounts	(38,879)		(228,129)
Currency translation adjustment, pre-tax	44,328		(25,451)
Currency translation adjustment, tax effect	0		0
Change in unrealized currency translation adjustments	44,328	26,056	(25,451)	24,382					(25,451)	24,382
Net pension asset, pre-tax	2,790		8,372
Net pension asset, tax effect	(976)		(2,930)
Met pension asset, after-tax amounts	1,814		5,442
Other comprehensive income (loss), pre-tax	(12,696)		(368,047)
Other comprehensive income (loss), tax effect	$ 19,959		$ 119,909

[1] Net investment gains in the consolidated statements of operations.

[2] Other operating costs and expenses in the consolidated statements of operations.

[3] Income tax expense in the consolidated statements of operations.