Reinsurance And Trust Agreements (Details) $ in Thousands				12 Months Ended
	Dec. 01, 2015 USD ($) item	Nov. 18, 2014 USD ($)	Apr. 24, 2014 USD ($)	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Effects of Reinsurance [Line Items]
Amount on deposit in trust accounts				$ 454,384
Reinsurance coverage amount				$ 498,031	$ 492,084	$ 213,813
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 Agreement 1 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	300,000		250,000
Kilimanjaro Re Limited [Member] | Catastrophe Reinsurance Agreement 2 [Member]
Effects of Reinsurance [Line Items]
Reinsurance coverage amount	$ 325,000		$ 200,000