Available For Sale Securities (Amortized Cost And Estimated Fair Value Of Investments Classified As Available For Sale By Contractual Maturity) (Details) $ in Thousands	Sep. 30, 2016 USD ($)
Investments [Abstract]
Due within one year, Amortized Cost	$ 227,013
Due after one year through five years, Amortized Cost	504
Fixed maturities investments excluding mortgage-backed and asset-backed securities, Amortized Cost	227,517
Mortgage-backed and asset-backed securities, Amortized Cost	45,464
Total fixed maturities investments, Amortized Cost	272,981
Due within one year, Estimated Fair Value	227,101
Due after one year through five years, Estimated Fair Value	511
Fixed maturities investments excluding mortgage-backed and asset-backed securities, Estimated Fair Value	227,612
Mortgage-backed and asset-backed securities, Estimated Fair Value	45,682
Total fixed maturities investments, Estimated Fair Value	$ 273,294