Short-Term And Long-Term Investments (Schedule Of Amortized Cost And Fair Value Of Fixed Maturities By Contractual Years-To-Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Investments [Abstract]
Cost or Amortized Cost, Fixed Maturities, One year or less	$ 363,569
Cost or Amortized Cost, Fixed Maturities, Over one year	483,607
Cost or Amortized Cost	847,176
Fair Value, Fixed Maturities, One year or less	363,877
Fair Value, Fixed Maturities, Over one year	482,917
Fair Value	$ 846,794