Reinsurance And Trust Agreements (Details) $ in Thousands	Nov. 18, 2014 USD ($)	Apr. 24, 2014 USD ($) item	Sep. 30, 2015 USD ($)
Effects of Reinsurance [Line Items]
Amount on deposit in trust accounts			$ 306,214
Kilimanjaro Re Limited [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item		2
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	$ 500,000
Catastrophe reinsurance bonds, funded amount	$ 500,000	$ 450,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member] | Southeastern United States [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		250,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member] | Southeast, Mid-Atlantic And Northeast United States And Puerto Rico [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		$ 200,000