Fair Value Measurements (Schedule Of Fair Values Of Financial Instruments Measured On Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Total assets	$ 130,994	$ 168,618
Money Market Funds [Member]
Cash	65,522	79,945
Bank Time Deposits [Member]
Cash	1,511	7,082
Certificates of Deposit [Member]
Investments	17,045	8,000
Equity Securities [Member]
Investments	220	2
Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	7,560	15,006
Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	14,471	16,228
Debt Securities Issued By Foreign Governments [Member]
Investments	6,368	6,544
Corporate Debt Securities [Member]
Investments	18,297	35,811
Level 1 [Member]
Total assets	130,994	168,618
Level 1 [Member] | Money Market Funds [Member]
Cash	65,522	79,945
Level 1 [Member] | Bank Time Deposits [Member]
Cash	1,511	7,082
Level 1 [Member] | Certificates of Deposit [Member]
Investments	17,045	8,000
Level 1 [Member] | Equity Securities [Member]
Investments	220	2
Level 1 [Member] | Debt Securities Issued By The U.S Treasury And Other U.S Government Corporations And Agencies [Member]
Investments	7,560	15,006
Level 1 [Member] | Debt Securities Issued By States Of The United States And Political Subdivisions Of The States [Member]
Investments	14,471	16,228
Level 1 [Member] | Debt Securities Issued By Foreign Governments [Member]
Investments	6,368	6,544
Level 1 [Member] | Corporate Debt Securities [Member]
Investments	18,297	35,811
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