Significant Accounting Policies	9 Months Ended
Sep. 30, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies (a) Restricted Cash Restricted cash represents cash and cash equivalents that the Company is a) holding for the benefit of a third party and is legally or contractually restricted as to withdrawal or usage for general corporate purposes; and b) not replaceable by another type of asset other than cash or cash equivalents, under the terms of the Company's contractual arrangements with such third parties. Restricted cash includes cash and cash equivalents held pursuant to the terms of the Company's contractual obligations of the transaction described in Note 3(e), "Acquisitions and Disposals - Sale of Life Reinsurance Subsidiary." (b) Reinsurance During the three months ended September 30, 2014, the Company recorded $20.0 million, net of tax, to premiums earned and associated tax accruals related to reinstatement premiums due under assumed reinsurance contracts arising from unpaid losses and loss expenses reported in a prior period. We evaluated the quantitative and qualitative aspects of this correction and concluded that the impact of recognizing it was not material to the consolidated financial statements, nor is it material to previously issued consolidated financial statements in prior periods. (c) Recent Accounting Pronouncements In February 2015, the Financial Accounting Standards Board ("FASB") issued an accounting standards update concerning consolidation of certain legal entities. Under this new guidance, all legal entities are required to evaluate whether they should consolidate certain legal entities. The guidance: (1) modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities ("VIEs") or voting interest entities; (2) eliminates the presumption that a general partner should consolidate a limited partnership; (3) affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships; and (4) provides a scope exception from consolidation guidance for certain reporting entities. Upon adoption of the new guidance, differing requirements for performing a consolidation analysis under existing GAAP will be eliminated, and all reporting entities will now fall within the scope of the Accounting Standards Codification Subtopic 810-10, Consolidation-Overall, unless a specific exception applies. Under this Subtopic, there are only two primary models for determining whether consolidation is appropriate - a voting interest entity model, and a variable interest entity model. The guidance is effective for public business entities for annual periods beginning after December 15, 2015, and interim and annual periods thereafter, with early adoption permitted. The Company is currently evaluating the impact of this guidance. In April 2015, the FASB issued an accounting standards update concerning the presentation of deferred debt issuance costs in an entity's balance sheet. Under this new guidance, which is part of the FASB's initiative to reduce complexity in accounting standards while maintaining or improving the usefulness of the information provided to users of financial statements, debt issuance costs related to a recognized debt liability must be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. In addition, the guidance also requires that the amortization of such costs be reported as interest expense. The guidance is effective for public business entities for annual periods beginning after December 15, 2015, and interim and annual periods thereafter, with early adoption permitted for financial statements that have not been previously issued. This guidance will not have a material impact on the Company's financial condition, results of operations or cash flows. In May 2015, the FASB issued an accounting standards update concerning investments for which management estimates fair value using net asset value per share (or its equivalent) as a practical expedient. Under the guidance, such investments will no longer be reported within the fair value hierarchy. Removing those investments from the fair value hierarchy not only eliminates the diversity in practice resulting from the way in which investments measured at net asset value per share (or its equivalent) with future redemption dates are classified, but also ensures that all investments categorized in the fair value hierarchy are classified using a consistent approach. Investments that calculate net asset value per share (or its equivalent), but for which the practical expedient is not applied, will continue to be included in the fair value hierarchy. A reporting entity should continue to disclose information on investments for which fair value is measured at net asset value (or its equivalent) as a practical expedient to help users understand the nature and risks of the investments and whether the investments, if sold, are probable of being sold at amounts different from net asset value. The guidance is effective for public business entities for annual periods beginning after December 15, 2015 and interim and annual periods thereafter, with early adoption permitted. The Company is currently evaluating the impact of this guidance, but it is not expected to have a material impact on the Company's financial condition, results of operations or cash flows. In May 2015, the FASB issued an accounting standards update concerning the annual disclosure regarding the liability for unpaid claims and claims adjustment expenses for insurance entities. The guidance requires: (1) incurred and paid claims development information by accident year, on a net basis after reinsurance, for the number of years for which claims incurred typically remain outstanding, including the most recent reporting period, which need not exceed 10 years; (2) a reconciliation of incurred and paid claims development information to the aggregate carrying amount of the liability for unpaid claims and claim adjustment expenses, with separate disclosure of reinsurance recoverable on unpaid claims for each period presented in the statement of financial position; (3) for each accident year for which incurred claims development information is presented, the total of incurred but not reported ("IBNR") liabilities plus expected development on reported claims included in the liability for unpaid claims and claims adjustment expenses, accompanied by a description of reserving methodologies; (4) for each accident year for which incurred claims development information is presented, quantitative information about claim frequency (unless it is impracticable to do so) accompanied by a qualitative description of methodologies used for determining claim frequency information; and (5) for all claims, the average annual percentage payout of incurred claims by age for the same number of accident years as the disclosure for IBNR. The guidance recommends that insurance entities aggregate or disaggregate those disclosures so that useful information is not obscured by either the inclusion of a large amount of insignificant detail or the aggregation of items that have significantly different characteristics. The amendments also require insurance entities to disclose information about significant changes in methodologies and assumptions used to calculate the liability for unpaid claims and claim adjustment expenses, including reasons for the change and the effects on the financial statements. Additionally, the amendments require insurance entities to disclose for annual and interim reporting periods a rollforward of the liability for unpaid claims and claims adjustment expenses. Additional disclosures about liabilities for unpaid claims and claim adjustment expenses reported at present value include: (1) for each period presented in the statement of financial position, the aggregate amount of discount for the time value of money deducted to derive the liability for unpaid claims and claim adjustment expenses; (2) for each period presented in the statement of income, the amount of interest accretion recognized; and (3) the line items in the statement of income in which interest accretion is classified. The guidance is effective for public business entities for annual periods beginning after December 15, 2015 and interim periods within annual periods after December 15, 2016. Early adoption is permitted. The Company is currently evaluating the impact of this guidance, but it is not expected to have a material impact on the Company's financial condition, results of operations or cash flows. In September 2015, the FASB issued an accounting standards update concerning the accounting for measurement period adjustments following the completion of a business combination. The measurement period ends as soon as the acquirer receives the information it was seeking about facts and circumstances that existed as of the acquisition date or learns that more information is not obtainable; however, it shall not exceed one year from the acquisition date. Currently under GAAP, during the measurement period the acquirer shall recognize such adjustments to the provisional amounts as if the accounting for the business combination had been completed at the acquisition date, with a corresponding adjustment to goodwill, in the reporting period in which the adjustments are determined. The acquirer shall revise comparative information for prior periods presented in financial statements as needed as a result of the change to the provisional amounts calculated. Under the new guidance, although such adjustments shall still be calculated as if the accounting had been completed at the business combination date, the acquirer should recognize in its current-period earnings the cumulative effect of changes in depreciation, amortization, or other income effects, by line item, related to the periods subsequent to the acquisition date as a result of the adjustments. In addition, entities must present separately on the face of the income statement, or alternatively in the notes to the financial statements, the portion of such current period adjustments that would have been recorded in previous reporting periods, if the adjustments had been recognized at the acquisition date. The guidance is effective for provisional adjustments made by public business entities in annual periods beginning after December 15, 2015 - irrespective of the date of the business combination to which they relate - including interim periods within those fiscal years. Early adoption is permitted for financial statements that have not yet been made available for issuance. To the extent that the Company were to make material measurement period adjustments to provisional amounts recognized as part of the Catlin Acquisition, this could have a material impact on the Company's results of operations during the period in which such adjustments were made. The guidance is not expected to have a material impact on the Company's financial condition or cash flows.

Significant Accounting Policies

(a) Restricted Cash

Restricted cash represents cash and cash equivalents that the Company is a) holding for the benefit of a third party and is legally or contractually restricted as to withdrawal or usage for general corporate purposes; and b) not replaceable by another type of asset other than cash or cash equivalents, under the terms of the Company's contractual arrangements with such third parties. Restricted cash includes cash and cash equivalents held pursuant to the terms of the Company's contractual obligations of the transaction described in Note 3(e), "Acquisitions and Disposals - Sale of Life Reinsurance Subsidiary."

(b) Reinsurance

During the three months ended September 30, 2014, the Company recorded $20.0 million, net of tax, to premiums earned and associated tax accruals related to reinstatement premiums due under assumed reinsurance contracts arising from unpaid losses and loss expenses reported in a prior period. We evaluated the quantitative and qualitative aspects of this correction and concluded that the impact of recognizing it was not material to the consolidated financial statements, nor is it material to previously issued consolidated financial statements in prior periods.

In February 2015, the Financial Accounting Standards Board ("FASB") issued an accounting standards update concerning consolidation of certain legal entities. Under this new guidance, all legal entities are required to evaluate whether they should consolidate certain legal entities. The guidance: (1) modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities ("VIEs") or voting interest entities; (2) eliminates the presumption that a general partner should consolidate a limited partnership; (3) affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships; and (4) provides a scope exception from consolidation guidance for certain reporting entities. Upon adoption of the new guidance, differing requirements for performing a consolidation analysis under existing GAAP will be eliminated, and all reporting entities will now fall within the scope of the Accounting Standards Codification Subtopic 810-10, Consolidation-Overall, unless a specific exception applies. Under this Subtopic, there are only two primary models for determining whether consolidation is appropriate - a voting interest entity model, and a variable interest entity model. The guidance is effective for public business entities for annual periods beginning after December 15, 2015, and interim and annual periods thereafter, with early adoption permitted. The Company is currently evaluating the impact of this guidance.

In April 2015, the FASB issued an accounting standards update concerning the presentation of deferred debt issuance costs in an entity's balance sheet. Under this new guidance, which is part of the FASB's initiative to reduce complexity in accounting standards while maintaining or improving the usefulness of the information provided to users of financial statements, debt issuance costs related to a recognized debt liability must be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. In addition, the guidance also requires that the amortization of such costs be reported as interest expense. The guidance is effective for public business entities for annual periods beginning after December 15, 2015, and interim and annual periods thereafter, with early adoption permitted for financial statements that have not been previously issued. This guidance will not have a material impact on the Company's financial condition, results of operations or cash flows.

In May 2015, the FASB issued an accounting standards update concerning investments for which management estimates fair value using net asset value per share (or its equivalent) as a practical expedient. Under the guidance, such investments will no longer be reported within the fair value hierarchy. Removing those investments from the fair value hierarchy not only eliminates the diversity in practice resulting from the way in which investments measured at net asset value per share (or its equivalent) with future redemption dates are classified, but also ensures that all investments categorized in the fair value hierarchy are classified using a consistent approach. Investments that calculate net asset value per share (or its equivalent), but for which the practical expedient is not applied, will continue to be included in the fair value hierarchy. A reporting entity should continue to disclose information on investments for which fair value is measured at net asset value (or its equivalent) as a practical expedient to help users understand the nature and risks of the investments and whether the investments, if sold, are probable of being sold at amounts different from net asset value. The guidance is effective for public business entities for annual periods beginning after December 15, 2015 and interim and annual periods thereafter, with early adoption permitted. The Company is currently evaluating the impact of this guidance, but it is not expected to have a material impact on the Company's financial condition, results of operations or cash flows.

In May 2015, the FASB issued an accounting standards update concerning the annual disclosure regarding the liability for unpaid claims and claims adjustment expenses for insurance entities. The guidance requires: (1) incurred and paid claims development information by accident year, on a net basis after reinsurance, for the number of years for which claims incurred typically remain outstanding, including the most recent reporting period, which need not exceed 10 years; (2) a reconciliation of incurred and paid claims development information to the aggregate carrying amount of the liability for unpaid claims and claim adjustment expenses, with separate disclosure of reinsurance recoverable on unpaid claims for each period presented in the statement of financial position; (3) for each accident year for which incurred claims development information is presented, the total of incurred but not reported ("IBNR") liabilities plus expected development on reported claims included in the liability for unpaid claims and claims adjustment expenses, accompanied by a description of reserving methodologies; (4) for each accident year for which incurred claims development information is presented, quantitative information about claim frequency (unless it is impracticable to do so) accompanied by a qualitative description of methodologies used for determining claim frequency information; and (5) for all claims, the average annual percentage payout of incurred claims by age for the same number of accident years as the disclosure for IBNR. The guidance recommends that insurance entities aggregate or disaggregate those disclosures so that useful information is not obscured by either the inclusion of a large amount of insignificant detail or the aggregation of items that have significantly different characteristics. The amendments also require insurance entities to disclose information about significant changes in methodologies and assumptions used to calculate the liability for unpaid claims and claim adjustment expenses, including reasons for the change and the effects on the financial statements. Additionally, the amendments require insurance entities to disclose for annual and interim reporting periods a rollforward of the liability for unpaid claims and claims adjustment expenses. Additional disclosures about liabilities for unpaid claims and claim adjustment expenses reported at present value include: (1) for each period presented in the statement of financial position, the aggregate amount of discount for the time value of money deducted to derive the liability for unpaid claims and claim adjustment expenses; (2) for each period presented in the statement of income, the amount of interest accretion recognized; and (3) the line items in the statement of income in which interest accretion is classified. The guidance is effective for public business entities for annual periods beginning after December 15, 2015 and interim periods within annual periods after December 15, 2016. Early adoption is permitted. The Company is currently evaluating the impact of this guidance, but it is not expected to have a material impact on the Company's financial condition, results of operations or cash flows.

In September 2015, the FASB issued an accounting standards update concerning the accounting for measurement period adjustments following the completion of a business combination. The measurement period ends as soon as the acquirer receives the information it was seeking about facts and circumstances that existed as of the acquisition date or learns that more information is not obtainable; however, it shall not exceed one year from the acquisition date. Currently under GAAP, during the measurement period the acquirer shall recognize such adjustments to the provisional amounts as if the accounting for the business combination had been completed at the acquisition date, with a corresponding adjustment to goodwill, in the reporting period in which the adjustments are determined. The acquirer shall revise comparative information for prior periods presented in financial statements as needed as a result of the change to the provisional amounts calculated. Under the new guidance, although such adjustments shall still be calculated as if the accounting had been completed at the business combination date, the acquirer should recognize in its current-period earnings the cumulative effect of changes in depreciation, amortization, or other income effects, by line item, related to the periods subsequent to the acquisition date as a result of the adjustments. In addition, entities must present separately on the face of the income statement, or alternatively in the notes to the financial statements, the portion of such current period adjustments that would have been recorded in previous reporting periods, if the adjustments had been recognized at the acquisition date. The guidance is effective for provisional adjustments made by public business entities in annual periods beginning after December 15, 2015 - irrespective of the date of the business combination to which they relate - including interim periods within those fiscal years. Early adoption is permitted for financial statements that have not yet been made available for issuance. To the extent that the Company were to make material measurement period adjustments to provisional amounts recognized as part of the Catlin Acquisition, this could have a material impact on the Company's results of operations during the period in which such adjustments were made. The guidance is not expected to have a material impact on the Company's financial condition or cash flows.