Goodwill and Intangible Assets Gross Values And Amortization Of Intangible Assets - (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Goodwill And Intangible Assets [Line Items]
Gross intangible assets excluding goodwill	$ 310,117	$ 310,117
Accumulated amortization	150,513	123,027
Definite Lived Intangible Assets [Member]
Goodwill And Intangible Assets [Line Items]
Gross intangible assets excluding goodwill	302,767	302,767
Accumulated amortization	150,513	123,027
Definite Lived Intangible Assets [Member] | Unpaid Losses And Loss Expenses [Member]
Goodwill And Intangible Assets [Line Items]
Gross intangible assets excluding goodwill	191,196	191,196
Accumulated amortization	131,908	115,958
Definite Lived Intangible Assets [Member] | Renewal Rights [Member]
Goodwill And Intangible Assets [Line Items]
Gross intangible assets excluding goodwill	48,163	48,163
Accumulated amortization	12,273	5,432
Definite Lived Intangible Assets [Member] | Customer Relationships [Member]
Goodwill And Intangible Assets [Line Items]
Gross intangible assets excluding goodwill	63,408	63,408
Accumulated amortization	6,332	1,637
Indefinite Lived Intangible Assets [Member] | Insurance Licenses [Member]
Goodwill And Intangible Assets [Line Items]
Gross intangible assets excluding goodwill	$ 7,350	$ 7,350