Cash, Cash Equivalents And Short-Term Investments (Unrealized Gains And Losses Related To Short-Term Investments Designated As Available-For-Sale) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	$ 396,007	$ 338,981
Gross Unrealized Gain	42	58
Gross Unrealized Loss	(153)	(48)
Cumulative Translation Adjustment	(2,484)	(3,829)
Fair Value	393,412	335,162
Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	142,058	141,340
Fair Value	142,058	141,340
Money Market Accounts [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	88,205	20,656
Fair Value	88,205	20,656
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost		1,465
Gross Unrealized Gain		1
Fair Value		1,466
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	71,964	8,708
Gross Unrealized Gain	16
Gross Unrealized Loss	(146)	(20)
Cumulative Translation Adjustment	(1,218)	(910)
Fair Value	70,616	7,778
U.S. Treasuries And Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	72,459	135,953
Gross Unrealized Gain	26
Gross Unrealized Loss		(28)
Fair Value	72,485	135,925
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	18,409	27,947
Gross Unrealized Gain		57
Gross Unrealized Loss	(7)
Cumulative Translation Adjustment	(1,266)	(2,919)
Fair Value	17,136	25,085
Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost	2,912	2,912
Fair Value	$ 2,912	$ 2,912