Fair Value Measurements (Schedule Of Fair Values Of Financial Instruments Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Total assets	$ 213,469	$ 208,089
Business Combination, Contingent Consideration, Liability	14,600	30,600
Derivative Liability	1,450	1,450
Financial Liabilities Fair Value Disclosure	16,050	32,050
Money Market Funds [Member]
Cash	56,307	46,867
Bank Time Deposits [Member]
Cash	2,448	3,004
Commercial Paper [Member]
Cash	2,997
Certificates of Deposit [Member]
Investments	64	60
Equity Securities [Member]
Investments	17,970	22,654
Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	48,625	40,652
Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	7,354	6,103
Corporate Debt Securities [Member]
Investments	77,704	88,749
Level 1 [Member]
Total assets	74,277	69,521
Business Combination, Contingent Consideration, Liability	0	0
Derivative Liability	0	0
Financial Liabilities Fair Value Disclosure	0	0
Level 1 [Member] \| Money Market Funds [Member]
Cash	56,307	46,867
Level 1 [Member] \| Bank Time Deposits [Member]
Cash	0	0
Level 1 [Member] \| Commercial Paper [Member]
Cash	0
Level 1 [Member] \| Certificates of Deposit [Member]
Investments	0	0
Level 1 [Member] \| Equity Securities [Member]
Investments	17,970	22,654
Level 1 [Member] \| Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	0	0
Level 1 [Member] \| Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	0	0
Level 1 [Member] \| Corporate Debt Securities [Member]
Investments	0	0
Level 2 [Member]
Total assets	139,192	138,568
Business Combination, Contingent Consideration, Liability	0	0
Derivative Liability	1,450	1,450
Financial Liabilities Fair Value Disclosure	1,450	1,450
Level 2 [Member] \| Money Market Funds [Member]
Cash	0	0
Level 2 [Member] \| Bank Time Deposits [Member]
Cash	2,448	3,004
Level 2 [Member] \| Commercial Paper [Member]
Cash	2,997
Level 2 [Member] \| Certificates of Deposit [Member]
Investments	64	60
Level 2 [Member] \| Equity Securities [Member]
Investments	0	0
Level 2 [Member] \| Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	48,625	40,652
Level 2 [Member] \| Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	7,354	6,103
Level 2 [Member] \| Corporate Debt Securities [Member]
Investments	77,704	88,749
Level 3 [Member]
Total assets	0	0
Business Combination, Contingent Consideration, Liability	14,600	30,600
Derivative Liability	0	0
Financial Liabilities Fair Value Disclosure	14,600	30,600
Level 3 [Member] \| Money Market Funds [Member]
Cash	0	0
Level 3 [Member] \| Bank Time Deposits [Member]
Cash	0	0
Level 3 [Member] \| Commercial Paper [Member]
Cash	0
Level 3 [Member] \| Certificates of Deposit [Member]
Investments	0	0
Level 3 [Member] \| Equity Securities [Member]
Investments	0	0
Level 3 [Member] \| Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	0	0
Level 3 [Member] \| Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	0	0
Level 3 [Member] \| Corporate Debt Securities [Member]
Investments	$ 0	$ 0

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Amount of liability recognized arising from contingent consideration in a business combination.

+ References

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-Publisher FASB
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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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6526789

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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 1
-Subparagraph a, f, g
-Article 7

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