Marketable Securities (Contractual Maturities Of Marketable Securities) (Details) $ in Thousands	Jun. 30, 2015 USD ($)
Marketable Securities [Abstract]
Due in one year or less, Amortized Cost	$ 114,841
Due after one through two years, Amortized Cost	66,170
Total marketable securities, Amortized Cost	181,011
Due in one year or less, Fair Value	114,783
Due after one through two years, Fair Value	66,087
Total marketable securities, Fair Value	$ 180,870