Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Related party transactions (Details) (USD $)	3 Months Ended		9 Months Ended
Related party transactions (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Narragansett Bay Insurance Company	Sep. 30, 2013 Narragansett Bay Insurance Company	Sep. 30, 2014 Pine Brook Road Partners, LLC	Dec. 31, 2013 Pine Brook Road Partners, LLC	Sep. 30, 2014 Third Point Loan L.L.C Investments in Securities and Derivative Contract	Dec. 31, 2013 Third Point Loan L.L.C Investments in Securities and Derivative Contract
Related Party Transaction [Line Items]
Gross premiums written	$ 126,403,000	$ 45,425,000	$ 359,498,000	$ 239,660,000	$ 5,300,000	$ 4,600,000
Ownership percentage							12.00%	12.00%
Estimated fair value of investment									$ 55,200,000	$ 147,200,000