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			$ 404,008
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
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		$ 250,000
Catastrophe reinsurance bonds funded amount		450,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 2 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		$ 200,000
Catastrophe reinsurance bonds funded amount	$ 500,000