Other Comprehensive Income (Loss) (Components Of Comprehensive Income (Loss) In The Consolidated Statements Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Before Tax	$ (961,050)	$ (339,110)
Total, Tax Effect	116,707	39,290
Total, Net of Tax	(844,343)	(299,820)
URA(D) On Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(932,309)	(329,166)
Tax Effect	117,132	40,551
Net of Tax	(815,177)	(288,615)
Reclassification, Before Tax	4,902	(3,542)
Reclassification, Tax Effect	(724)	(124)
Reclassification, Net of Tax	4,178	(3,666)
Total, Net of Tax	(810,999)	(292,281)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(34,603)	(8,988)
Tax Effect	501	(594)
Net of Tax	(34,102)	(9,582)
Total, Net of Tax	(34,102)	(9,582)
Benefit Plan Net Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification, Before Tax	960	2,586
Reclassification, Tax Effect	(202)	(543)
Reclassification, Net of Tax	758	2,043
Total, Net of Tax	$ 758	$ 2,043