Cash, Cash Equivalents And Short-Term Investments (Contractual Maturities Of Short-Term Investments Designated As Available-For-Sale) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost, Due in less than 1 year	$ 58,363
Fair Value, Due in less than 1 year	57,222
Adjusted Cost, Due in 1 to 5 years	101,641
Fair Value, Due in 1 to 5 years	98,028
Adjusted Cost, Total	160,004
Fair Value, Total	155,250
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost, Due in 1 to 5 years	1,432
Fair Value, Due in 1 to 5 years	1,434
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost, Due in 1 to 5 years	17,835
Fair Value, Due in 1 to 5 years	15,487
U.S. Treasuries And Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost, Due in less than 1 year	46,476
Fair Value, Due in less than 1 year	46,479
Adjusted Cost, Due in 1 to 5 years	72,530
Fair Value, Due in 1 to 5 years	72,546
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost, Due in less than 1 year	8,975
Fair Value, Due in less than 1 year	7,831
Adjusted Cost, Due in 1 to 5 years	9,844
Fair Value, Due in 1 to 5 years	8,561
Time Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Cost, Due in less than 1 year	2,912
Fair Value, Due in less than 1 year	$ 2,912