Other Comprehensive Income (Loss) (Summary Of Tax Expense (Benefit) Of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Other Comprehensive Income (Loss), Tax [Abstract]
Net holding gains (losses) arising during the period	$ 34,332	$ (32,548)	$ 75,150	$ (60,778)
Reclassification adjustments for net gains (losses) included in net income (loss)	214	(1,566)	148	(1,349)
Change in net unrealized gains (losses) on available-for-sale investments	34,546	(34,114)	75,298	(62,127)
Change in foreign currency translation adjustments	0	(4,288)	0	(3,522)
Change in net actuarial pension loss	137	192	499	328
Total	$ 34,683	$ (38,210)	$ 75,797	$ (65,321)

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) 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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