Short-term Investments (Estimated Fair Value Of Short-Term Investments By Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Short-Term Investments And Fair Value Measurement [Abstract]
Due within one year	$ 138,342
Due after one year and through 5 years	524,210
Due after 5 years and through 10 years	1,755
Due after 10 years	45,125
Total short-term investments	$ 709,432