Reinsurance And Trust Agreements (Narrative) (Details) $ in Thousands	Dec. 01, 2015 USD ($) item	Nov. 18, 2014 USD ($)	Apr. 24, 2014 USD ($) item	Sep. 30, 2016 USD ($)
Effects of Reinsurance [Line Items]
Amount on deposit in trust accounts				$ 349,867
Kilimanjaro Re Limited [Member]
Effects of Reinsurance [Line Items]
Number of collateralized reinsurance agreements | item	2		2
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount		$ 500,000
Catastrophe reinsurance bonds, funded amount	$ 625,000	$ 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
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 1 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	300,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 2 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	$ 325,000