Summary Of Significant Accounting Policies (Amortized Cost And Fair Value Of Short-Term Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Accounting Policies [Abstract]
Due in one year or less, Amortized Cost	$ 41,272
Due in one year or less, Estimated Fair Value	41,293
Due after one through two years, Amortized Cost	34,517
Due after one through two years, Estimated Fair Value	34,544
Total short-term investments, Amortized Cost	75,789
Total short-term investments, Estimated Fair Value	$ 75,837