v2.4.0.6

Fair Value Measurements Fair Value Measurements (Quantitative Information Used As Level 3 Inputs) (Details) (USD $) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2012 | Mar. 31, 2011 | Dec. 31, 2011
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Net premiums written | $ 492,575,000 | $ 452,575,000 |
Net reserve for claims and claim expenses | 1,858,203,000 |  | 1,992,354,000
Senior secured bank loan funds [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Investment in closed end fund | 21,000,000 |  |
Significant Unobservable Inputs (Level 3) [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 494,520,000 |  |
Other assets and (liabilities). fair value | 48,145,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Corporate [Member] | Discounted Cash Flow Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 17,584,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Corporate [Member] | Discounted Cash Flow Valuation Technique [Member] | Weighted Average or Actual [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Credit spread | 4.10% |  |
Illiquidity premium | 1.00% |  |
Risk-free rate | 0.20% |  |
Dividend rate | 5.90% |  |
Significant Unobservable Inputs (Level 3) [Member] | Corporate [Member] | Internal Valuation Model Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 10,254,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Investments [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 27,838,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Private Equity Funds [Member] | Net Asset Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 389,451,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Private Equity Funds [Member] | Net Asset Valuation Technique [Member] | Minimum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | (6.00%) |  |
Significant Unobservable Inputs (Level 3) [Member] | Private Equity Funds [Member] | Net Asset Valuation Technique [Member] | Maximum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | 64.40% |  |
Significant Unobservable Inputs (Level 3) [Member] | Private Equity Funds [Member] | Net Asset Valuation Technique [Member] | Weighted Average or Actual [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | 8.40% |  |
Significant Unobservable Inputs (Level 3) [Member] | Senior secured bank loan funds [Member] | Net Asset Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 21,000,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Senior secured bank loan funds [Member] | Net Asset Valuation Technique [Member] | Weighted Average or Actual [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | 2.10% |  |
Significant Unobservable Inputs (Level 3) [Member] | Hedge funds [Member] | Net Asset Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 6,746,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Hedge funds [Member] | Net Asset Valuation Technique [Member] | Minimum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | 0.00% |  |
Significant Unobservable Inputs (Level 3) [Member] | Hedge funds [Member] | Net Asset Valuation Technique [Member] | Maximum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | 0.70% |  |
Significant Unobservable Inputs (Level 3) [Member] | Hedge funds [Member] | Net Asset Valuation Technique [Member] | Weighted Average or Actual [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Estimated performance | 0.20% |  |
Significant Unobservable Inputs (Level 3) [Member] | Miscellaneous other investments [Member] | Discounted Cash Flow Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 1,340,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Miscellaneous other investments [Member] | Discounted Cash Flow Valuation Technique [Member] | Weighted Average or Actual [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Credit spread | 7.50% |  |
Illiquidity premium | 1.00% |  |
Risk-free rate | 0.50% |  |
Significant Unobservable Inputs (Level 3) [Member] | Other Investments [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Assets, fair value | 418,537,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Other assets and (liabilities). fair value | 6,163,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique [Member] | Minimum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Net premiums written | 0 |  |
Contract period | 183 days |  |
Net reserve for claims and claim expenses | 0 |  |
Significant Unobservable Inputs (Level 3) [Member] | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique [Member] | Maximum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Net premiums written | 6,000,000 |  |
Contract period | 365 days |  |
Net reserve for claims and claim expenses | 0 |  |
Significant Unobservable Inputs (Level 3) [Member] | Energy And Weather Contracts [Member] | Spread Option, Quanto, Black Scholes and Simulation Valuation Techniques [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Other assets and (liabilities). fair value | 26,565,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Energy And Weather Contracts [Member] | Spread Option, Quanto, Black Scholes and Simulation Valuation Techniques [Member] | Minimum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Correlation | 0.00% |  |
Volatility | 7.00% |  |
Commodity curve | 1.77 |  |
Weather curve | 19,000 |  |
Counterparty default risk | 0.00% |  |
Significant Unobservable Inputs (Level 3) [Member] | Energy And Weather Contracts [Member] | Spread Option, Quanto, Black Scholes and Simulation Valuation Techniques [Member] | Maximum [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Correlation | 100.00% |  |
Volatility | 350.00% |  |
Commodity curve | 66 |  |
Weather curve | 5,000,000 |  |
Counterparty default risk | 22.50% |  |
Significant Unobservable Inputs (Level 3) [Member] | Other [Member] | Internal Valuation Model Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Other assets and (liabilities). fair value | 1,250,000 |  |
Significant Unobservable Inputs (Level 3) [Member] | Other [Member] | Net Asset Valuation Technique [Member] |  |  |
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] |  |  |
Other assets and (liabilities). fair value | $ 14,167,000 |  |

X
- Definition Assets (Liabilities), Fair Value Disclosure, Recurring + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Measure of dispersion, in percentage terms (for instance, the standard deviation or variance). + References No definition available. + Details
Name: | rnr_FairValueAssumptionsExpectedDerivativeVolatilityRate
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price). + References No definition available. + Details
Name: | rnr_FairValueAssumptionsExpectedDividendRate
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Risk-free interest rate assumption used in valuing an instrument. + References No definition available. + Details
Name: | rnr_FairValueAssumptionsRiskFreeInterestRate
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Details
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Data Type: | xbrli:stringItemType
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- Definition Fair Value Inputs, Contract Period + References No definition available. + Details
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Namespace Prefix: | rnr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Definition Fair Value Inputs, Correlation + References No definition available. + Details
Name: | rnr_FairValueInputsCorrelation
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Risk that one party to the contract will default expressed as a percentage, used as an input to measure fair value. + References No definition available. + Details
Name: | rnr_FairValueInputsCounterpartyCreditRisk
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair Value Inputs, Degree Days Farenheit + References No definition available. + Details
Name: | rnr_FairValueInputsDegreeDaysFarenheit
Namespace Prefix: | rnr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Adjustment to the discount rate used to measure fair value for lack of ability to convert business interests into cash quickly. + References No definition available. + Details
Name: | rnr_FairValueInputsDiscountForLackOfMarketability
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Risk associated with risk of default, credit spread risk and downgrade risk, expressed as a percentage, used as an input to measure fair value. + References No definition available. + Details
Name: | rnr_FairValueInputsEntityCreditRisk
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimated percentage return for the period on fair value at beginning of period. + References No definition available. + Details
Name: | rnr_FairValueInputsEstimatedPerformance
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Fair Value Inputs, Price Per Commodity + References No definition available. + Details
Name: | rnr_FairValueInputsPricePerCommodity
Namespace Prefix: | rnr_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents senior secured bank loan funds in a closed end fund, which the Company has no right to redeem. + References No definition available. + Details
Name: | rnr_InvestmentInClosedEndFund
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-5 -Paragraph 11 -Subparagraph b -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a),(b),(c) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Premiums written for all insurance and reinsurance contracts, after adding premiums assumed from other insurers and subtracting any amounts ceded to another insurer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 17 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 113 -Paragraph 27 -Subparagraph a, b -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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