Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands		6 Months Ended
	May. 01, 2015	Jun. 30, 2015
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified indefinite life intangible assets		$ 673,000
Identified definite life intangible assets		$ 315,000
Catlin Group Limited
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified indefinite life intangible assets	$ 673,000
Identified definite life intangible assets	315,000
Total identified intangible assets	988,000
Catlin Group Limited | Syndicate capacity
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified indefinite life intangible assets	660,000
Catlin Group Limited | Insurance licenses
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified indefinite life intangible assets	13,000
Catlin Group Limited | Lloyds - Managing agent contracts
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified definite life intangible assets	15,000
Estimated useful life		15 years
Catlin Group Limited | Distribution network
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified definite life intangible assets	290,000
Estimated useful life		20 years
Catlin Group Limited | Trademarks / Trade names
Schedule Of Acquired Intangible Assets By Major Class [Line Items]
Identified definite life intangible assets	$ 10,000
Estimated useful life		2 years