Other Comprehensive Income (Loss) (Components Of Comprehensive Income (Loss) In The Consolidated Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Before Tax	$ (339,110)	$ (334,581)
Total, Tax Effect	39,290	36,678
Total, Net of Tax	(299,820)	(297,903)
URA(D) On Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(329,166)	(315,200)
Tax Effect	40,551	35,802
Net of Tax	(288,615)	(279,398)
Reclassification, Before Tax	(3,542)	38,177
Reclassification, Tax Effect	(124)	(6,778)
Reclassification, Net of Tax	(3,666)	31,399
URA(D) On Securities OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Net of Tax	(292,281)	(247,999)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(8,988)	(58,723)
Tax Effect	(594)	7,899
Net of Tax	(9,582)	(50,824)
Total, Net of Tax	(9,582)	(50,824)
Benefit Plan Net Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification, Before Tax	2,586	1,165
Reclassification, Tax Effect	(543)	(245)
Reclassification, Net of Tax	2,043	920
Total, Net of Tax	$ 2,043	$ 920