Marketable Securities (Schedule Of Marketable Securities Classified As Cash Equivalents) (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Foreign Accounts
Gain (Loss) on Investments [Line Items]
Cash And Marketable Securities Held In Foreign Accounts	$ 1,000,000.0	$ 672,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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