Consolidated Statement Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 565,350	$ 141,555	$ 470,907
Other comprehensive (loss) income:
Change in unrealized gains on securities, net of taxes of $18,945, $158,653, and $(135,743), respectively	(36,176)	(297,639)	267,011
Change in other-than-temporary impairment gains, net of taxes of $971, $2,240, and $(90), respectively	(1,802)	(4,160)	167
Change in foreign currency translation, net of taxes of $(429), $5,100, and $2,745, respectively	(51,372)	(143,023)	(88,944)
Amortization of pension and postretirement unrecognized net periodic benefit cost and change in funded status, net of taxes of $(35,224), $(4,091), and $26,534, respectively	65,403	7,604	(49,297)
Total other comprehensive (loss) income	(23,947)	(437,218)	128,937
Total comprehensive income (loss)	$ 541,403	$ (295,663)	$ 599,844