Fair Value Measurements (Schedule Of Fair Values Of Financial Instruments Measured On Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Total assets	$ 262,144	$ 246,340
Money Market Funds [Member]
Cash	101,232	99,351
Bank Time Deposits [Member]
Cash	22,773	22,093
Certificates of Deposit [Member]
Investments	14,402	34,876
Equity Securities [Member]
Investments	30,047	23,497
Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	23,702	6,450
Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	3,296	11,658
Debt Securities Issued By Foreign Governments [Member]
Investments	0	3,589
Corporate Debt Securities [Member]
Investments	66,692	44,826
Level 1 [Member]
Total assets	262,144	246,340
Level 1 [Member] | Money Market Funds [Member]
Cash	101,232	99,351
Level 1 [Member] | Bank Time Deposits [Member]
Cash	22,773	22,093
Level 1 [Member] | Certificates of Deposit [Member]
Investments	14,402	34,876
Level 1 [Member] | Equity Securities [Member]
Investments	30,047	23,497
Level 1 [Member] | Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	23,702	6,450
Level 1 [Member] | Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	3,296	11,658
Level 1 [Member] | Debt Securities Issued By Foreign Governments [Member]
Investments	0	3,589
Level 1 [Member] | Corporate Debt Securities [Member]
Investments	66,692	44,826
Level 2 [Member]
Total assets	0	0
Level 2 [Member] | Money Market Funds [Member]
Cash	0	0
Level 2 [Member] | Bank Time Deposits [Member]
Cash	0	0
Level 2 [Member] | Certificates of Deposit [Member]
Investments	0	0
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	0	0
Level 2 [Member] | Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	0	0
Level 2 [Member] | Debt Securities Issued By Foreign Governments [Member]
Investments	0	0
Level 2 [Member] | Corporate Debt Securities [Member]
Investments	0	0
Level 3 [Member]
Total assets	0	0
Level 3 [Member] | Money Market Funds [Member]
Cash	0	0
Level 3 [Member] | Bank Time Deposits [Member]
Cash	0	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] | Debt Securities Issued By Foreign Governments [Member]
Investments	0	0
Level 3 [Member] | Corporate Debt Securities [Member]
Investments	$ 0	$ 0