Fair Value Measurements (Schedule Of Fair Values Of Financial Instruments Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Total assets measured at fair value	$ 378,328	$ 418,334
Contingent consideration	8,864	37,887
Total liabilities measured at fair value	8,864	37,887
Money Market Funds [Member]
Money market and other funds	377,695	395,664
Corporate Debt Securities [Member]
Corporate debt securities	633	22,670
Level 1 [Member]
Total assets measured at fair value	377,695	395,664
Contingent consideration	0	0
Total liabilities measured at fair value	0	0
Level 1 [Member] \| Money Market Funds [Member]
Money market and other funds	377,695	395,664
Level 1 [Member] \| Corporate Debt Securities [Member]
Corporate debt securities	0	0
Level 2 [Member]
Total assets measured at fair value	633	623
Contingent consideration	0	0
Total liabilities measured at fair value	0	0
Level 2 [Member] \| Money Market Funds [Member]
Money market and other funds	0	0
Level 2 [Member] \| Corporate Debt Securities [Member]
Corporate debt securities	633	623
Level 3 [Member]
Total assets measured at fair value	0	22,047
Contingent consideration	8,864	37,887
Total liabilities measured at fair value	8,864	37,887
Level 3 [Member] \| Money Market Funds [Member]
Money market and other funds	0	0
Level 3 [Member] \| Corporate Debt Securities [Member]
Corporate debt securities	$ 0	$ 22,047

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

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