Variable Interest Entities	3 Months Ended
Mar. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES Effective January 1, 2012, the Company formed and launched a managed joint venture, Upsilon Reinsurance Ltd. ("Upsilon Re"), a Bermuda domiciled special purpose insurer ("SPI"), to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market for the 2012 underwriting year. The original business was written by Renaissance Reinsurance of Europe ("ROE"), a wholly owned subsidiary of RenaissanceRe, and included $37.4 million of gross premiums written incepting between January 1, 2012 and June 1, 2012. A portion of this business was in turn ceded to Upsilon Re under a fully-collateralized retrocessional reinsurance contract, effective January 1, 2012. In conjunction with the formation and launch of Upsilon Re, $16.8 million of non-voting Class B shares were sold to external investors, and the Company invested $48.8 million in Upsilon Re's non-voting Class B shares, representing a 74.5% ownership interest in Upsilon Re. The Class B shareholders participate in substantially all of the profits or losses of Upsilon Re while the Class B shares remain outstanding. The holders of Class B shares indemnify Upsilon Re against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. In addition, another third party investor supplied $17.6 million of capital through a reinsurance participation (a third party quota share agreement) with ROE alongside Upsilon Re. Inclusive of the reinsurance participation, the Company has a 61.4% participation in the original risks assumed by ROE. Both Upsilon Re and the reinsurance participation are managed by RUM in return for an expense override, as well as a potential underwriting profit commission. Upsilon Re is considered a VIE and the Company is considered the primary beneficiary. As a result, Upsilon Re is consolidated by the Company and all significant inter-company transactions have been eliminated. During February 2013, Upsilon Re redeemed a portion of its outstanding third party non-voting Class B shares for $20.5 million as a result of the scheduled expiration of certain risks underwritten by Upsilon Re. Following the redemption, third-party non-voting Class B Shares with a GAAP book value of $2.4 million as at March 31, 2013, remained outstanding. In addition, the Company has authorized the release of $23.0 million of collateral to a third party investor who participated in risks underwritten by ROE related to Upsilon Re through the reinsurance participation. Effective June 1, 2012, the Company formed and launched a managed joint venture, Timicuan Reinsurance III Limited ("Tim Re III"), a Bermuda domiciled SPI, to provide collateralized reinsurance in respect of a portfolio of Florida reinstatement premium protection ("RPP") contracts. The original business was written by Renaissance Reinsurance and DaVinci, and included $41.1 million of gross premiums written incepting June 1, 2012 and Renaissance Reinsurance and DaVinci ceded $37.7 million to Tim Re III under a fully-collateralized reinsurance contract. In conjunction with the formation and launch of Tim Re III, $44.8 million of non-voting Class B shares were sold to external investors. Additionally, $10.3 million of the non-voting Class B shares were acquired by the Company, representing an 18.6% ownership interest in Tim Re III. The Class B shareholders participate in substantially all of the profits or losses of Tim Re III while the Class B shares remain outstanding. The holders of Class B shares indemnify Tim Re III against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. In addition, another third party investor supplied $5.2 million of capital through a reinsurance participation with Renaissance Reinsurance and DaVinci, alongside Tim Re III. Inclusive of the reinsurance participation, the Company has a 17.1% participation in the original risks assumed by Renaissance Reinsurance and DaVinci related to Tim Re III. Both Tim Re III and the reinsurance participation are managed by RUM in return for a potential underwriting profit commission. Tim Re III is considered a VIE and the Company is considered the primary beneficiary. As a result, Tim Re III is consolidated by the Company and all significant inter-company transactions have been eliminated. Effective January 1, 2013, the Company formed and launched a managed joint venture, Upsilon Reinsurance II Ltd. ("Upsilon Re II"), a Bermuda domiciled SPI, to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market for the 2013 underwriting year. Original business will be written directly by Upsilon Re II and includes $53.5 million of gross premiums written incepting January 1, 2013 under fully-collateralized reinsurance contracts. In conjunction with the formation and launch of Upsilon Re II, $61.0 million of Upsilon Re II non-voting Class B shares were sold to external investors. Additionally, $76.4 million of the non-voting Class B shares were acquired by the Company, representing a 55.6% ownership interest in Upsilon Re II. The Class B shareholders participate in substantially all of the profits or losses of Upsilon Re II while the Class B shares remain outstanding. The holders of Class B shares indemnify Upsilon Re II against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. In addition, another third party investor supplied $17.5 million of capital through an insurance contract with the Company related to Upsilon Re II's reinsurance portfolio. Inclusive of the insurance contract, the Company has a 42.9% participation in the original risks assumed by Upsilon Re II. Both Upsilon Re II and the insurance contract are managed by RUM in return for an expense override, as well as a potential underwriting profit commission. Upsilon Re II is considered a VIE and the Company is considered the primary beneficiary. As a result, Upsilon Re II is consolidated by the Company and all significant inter-company transactions have been eliminated.

VARIABLE INTEREST ENTITIES

Effective January 1, 2012, the Company formed and launched a managed joint venture, Upsilon Reinsurance Ltd. ("Upsilon Re"), a Bermuda domiciled special purpose insurer ("SPI"), to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market for the 2012 underwriting year. The original business was written by Renaissance Reinsurance of Europe ("ROE"), a wholly owned subsidiary of RenaissanceRe, and included $37.4 million of gross premiums written incepting between January 1, 2012 and June 1, 2012. A portion of this business was in turn ceded to Upsilon Re under a fully-collateralized retrocessional reinsurance contract, effective January 1, 2012. In conjunction with the formation and launch of Upsilon Re, $16.8 million of non-voting Class B shares were sold to external investors, and the Company invested $48.8 million in Upsilon Re's non-voting Class B shares, representing a 74.5% ownership interest in Upsilon Re. The Class B shareholders participate in substantially all of the profits or losses of Upsilon Re while the Class B shares remain outstanding. The holders of Class B shares indemnify Upsilon Re against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. In addition, another third party investor supplied $17.6 million of capital through a reinsurance participation (a third party quota share agreement) with ROE alongside Upsilon Re. Inclusive of the reinsurance participation, the Company has a 61.4% participation in the original risks assumed by ROE. Both Upsilon Re and the reinsurance participation are managed by RUM in return for an expense override, as well as a potential underwriting profit commission. Upsilon Re is considered a VIE and the Company is considered the primary beneficiary. As a result, Upsilon Re is consolidated by the Company and all significant inter-company transactions have been eliminated.

During February 2013, Upsilon Re redeemed a portion of its outstanding third party non-voting Class B shares for $20.5 million as a result of the scheduled expiration of certain risks underwritten by Upsilon Re. Following the redemption, third-party non-voting Class B Shares with a GAAP book value of $2.4 million as at March 31, 2013, remained outstanding. In addition, the Company has authorized the release of $23.0 million of collateral to a third party investor who participated in risks underwritten by ROE related to Upsilon Re through the reinsurance participation.

Effective June 1, 2012, the Company formed and launched a managed joint venture, Timicuan Reinsurance III Limited ("Tim Re III"), a Bermuda domiciled SPI, to provide collateralized reinsurance in respect of a portfolio of Florida reinstatement premium protection ("RPP") contracts. The original business was written by Renaissance Reinsurance and DaVinci, and included $41.1 million of gross premiums written incepting June 1, 2012 and Renaissance Reinsurance and DaVinci ceded $37.7 million to Tim Re III under a fully-collateralized reinsurance contract. In conjunction with the formation and launch of Tim Re III, $44.8 million of non-voting Class B shares were sold to external investors. Additionally, $10.3 million of the non-voting Class B shares were acquired by the Company, representing an 18.6% ownership interest in Tim Re III. The Class B shareholders participate in substantially all of the profits or losses of Tim Re III while the Class B shares remain outstanding. The holders of Class B shares indemnify Tim Re III against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. In addition, another third party investor supplied $5.2 million of capital through a reinsurance participation with Renaissance Reinsurance and DaVinci, alongside Tim Re III. Inclusive of the reinsurance participation, the Company has a 17.1% participation in the original risks assumed by Renaissance Reinsurance and DaVinci related to Tim Re III. Both Tim Re III and the reinsurance participation are managed by RUM in return for a potential underwriting profit commission. Tim Re III is considered a VIE and the Company is considered the primary beneficiary. As a result, Tim Re III is consolidated by the Company and all significant inter-company transactions have been eliminated.

Effective January 1, 2013, the Company formed and launched a managed joint venture, Upsilon Reinsurance II Ltd. ("Upsilon Re II"), a Bermuda domiciled SPI, to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market for the 2013 underwriting year. Original business will be written directly by Upsilon Re II and includes $53.5 million of gross premiums written incepting January 1, 2013 under fully-collateralized reinsurance contracts. In conjunction with the formation and launch of Upsilon Re II, $61.0 million of Upsilon Re II non-voting Class B shares were sold to external investors. Additionally, $76.4 million of the non-voting Class B shares were acquired by the Company, representing a 55.6% ownership interest in Upsilon Re II. The Class B shareholders participate in substantially all of the profits or losses of Upsilon Re II while the Class B shares remain outstanding. The holders of Class B shares indemnify Upsilon Re II against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. In addition, another third party investor supplied $17.5 million of capital through an insurance contract with the Company related to Upsilon Re II's reinsurance portfolio. Inclusive of the insurance contract, the Company has a 42.9% participation in the original risks assumed by Upsilon Re II. Both Upsilon Re II and the insurance contract are managed by RUM in return for an expense override, as well as a potential underwriting profit commission. Upsilon Re II is considered a VIE and the Company is considered the primary beneficiary. As a result, Upsilon Re II is consolidated by the Company and all significant inter-company transactions have been eliminated.