Other Comprehensive Income (Summary Of Tax Expense (Benefit) Of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Comprehensive Income (Loss), Tax [Abstract]
Net holding gains (losses) arising during the period	$ 13,018	$ (24,047)	$ 88,168	$ (84,825)
Reclassification adjustments for net losses included in net income (loss)	54	2,810	202	1,461
Change in net unrealized gains (losses) on available-for-sale investments	13,072	(21,237)	88,370	(83,364)
Change in foreign currency translation adjustments	0	6,594	0	3,072
Change in net actuarial pension loss	123	135	622	463
Total	$ 13,195	$ (14,508)	$ 88,992	$ (79,829)

Amount of tax expense (benefit), before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount of tax expense (benefit), after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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