Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income, Net of Tax) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 348,419	$ 764,072	$ 555,767	$ 426,830
Other comprehensive loss before reclassifications	(111,887)	(115,676)	(333,650)	202,717
Amounts reclassified from accumulated other comprehensive income	9,506	11,350	23,921	30,199
Total other comprehensive (loss) income	(102,381)	(104,326)	(309,729)	232,916
Ending balance	246,038	659,746	246,038	659,746
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(173,511)	(18,937)	(127,711)	(38,767)
Other comprehensive loss before reclassifications	(68,499)	(54,264)	(114,299)	(34,434)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Total other comprehensive (loss) income	(68,499)	(54,264)	(114,299)	(34,434)
Ending balance	(242,010)	(73,201)	(242,010)	(73,201)
Unrealized gains on securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	627,477	837,038	793,082	526,071
Other comprehensive loss before reclassifications	(41,507)	(60,219)	(217,590)	235,940
Amounts reclassified from accumulated other comprehensive income	6,788	8,602	17,266	23,410
Total other comprehensive (loss) income	(34,719)	(51,617)	(200,324)	259,350
Ending balance	592,758	785,421	592,758	785,421
OTTI
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	25,419	28,811	26,594	26,427
Other comprehensive loss before reclassifications	(1,881)	(1,193)	(1,761)	1,211
Amounts reclassified from accumulated other comprehensive income	(33)	1,104	(1,328)	1,084
Total other comprehensive (loss) income	(1,914)	(89)	(3,089)	2,295
Ending balance	23,505	28,722	23,505	28,722
Pension under- funding
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(130,966)	(82,840)	(136,198)	(86,901)
Other comprehensive loss before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	2,751	1,644	7,983	5,705
Total other comprehensive (loss) income	2,751	1,644	7,983	5,705
Ending balance	$ (128,215)	$ (81,196)	$ (128,215)	$ (81,196)