Accumulated Other Comprehensive Income (Components of Accumulated Other Comprehensive Income, Net of Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income, beginning balance	$ 555,767	$ 426,830	$ 830,403
Amounts reclassified from accumulated other comprehensive income (loss)	(473,833)	88,088	(448,801)
Amounts reclassified from accumulated other comprehensive income (loss)	36,615	40,849	45,228
Net current-period other comprehensive (loss) income	(437,218)	128,937	(403,573)
Accumulated other comprehensive income, ending balance	118,549	555,767	426,830
Accumulated Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income, beginning balance	(127,711)	(38,767)	6,882
Amounts reclassified from accumulated other comprehensive income (loss)	(143,023)	(88,944)	(45,649)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Net current-period other comprehensive (loss) income	(143,023)	(88,944)	(45,649)
Accumulated other comprehensive income, ending balance	(270,734)	(127,711)	(38,767)
Accumulated Net Unrealized Investment Gain (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income, beginning balance	793,082	526,071	981,879
Amounts reclassified from accumulated other comprehensive income (loss)	(324,934)	235,000	(478,853)
Amounts reclassified from accumulated other comprehensive income (loss)	27,295	32,011	23,045
Net current-period other comprehensive (loss) income	(297,639)	267,011	(455,808)
Accumulated other comprehensive income, ending balance	495,443	793,082	526,071
Accumulated Other-than-Temporary Impairment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income, beginning balance	26,594	26,427	23,861
Amounts reclassified from accumulated other comprehensive income (loss)	(2,746)	(1,321)	(2,237)
Amounts reclassified from accumulated other comprehensive income (loss)	(1,414)	1,488	4,803
Net current-period other comprehensive (loss) income	(4,160)	167	2,566
Accumulated other comprehensive income, ending balance	22,434	26,594	26,427
Accumulated Defined Benefit Plans Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income, beginning balance	(136,198)	(86,901)	(182,219)
Amounts reclassified from accumulated other comprehensive income (loss)	(3,130)	(56,647)	77,938
Amounts reclassified from accumulated other comprehensive income (loss)	10,734	7,350	17,380
Net current-period other comprehensive (loss) income	7,604	(49,297)	95,318
Accumulated other comprehensive income, ending balance	$ (128,594)	$ (136,198)	$ (86,901)