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Fair Value Measurements (Quantitative Information Used As Level 3 Inputs) (Details) (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | ||
|---|---|---|---|
|
Mar. 31, 2013
|
Mar. 31, 2012
|
Dec. 31, 2012
|
|
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Net premiums written | $ 436,813 | $ 492,575 | |
| Reserve for claims and claim expenses | 1,755,783 | 1,879,377 | |
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Fair Value, Inputs, Level 3 [Member]
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|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 451,601 | ||
| Other assets and (liabilities). fair value | 21,328 | ||
|
Fair Value, 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 | 17,813 | ||
|
Fair Value, Inputs, Level 3 [Member] | Corporate [Member] | Discounted Cash Flow Valuation Technique [Member] | Weighted Average or Actual [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Credit spread | 2.40% | ||
| Liquidity premium | 1.00% | ||
| Risk-free rate | 0.10% | ||
| Dividend rate | 5.90% | ||
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Fair Value, Inputs, Level 3 [Member] | Corporate [Member] | Internal Valuation Model Valuation Technique [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 10,254 | ||
|
Fair Value, Inputs, Level 3 [Member] | Fixed maturity investments [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 28,067 | ||
|
Fair Value, Inputs, Level 3 [Member] | Private equity partnerships [Member] | Net Asset Valuation Technique [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 345,666 | ||
|
Fair Value, Inputs, Level 3 [Member] | Private equity partnerships [Member] | Net Asset Valuation Technique [Member] | Low [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | (12.00%) | ||
|
Fair Value, Inputs, Level 3 [Member] | Private equity partnerships [Member] | Net Asset Valuation Technique [Member] | Maximum [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | 120.00% | ||
|
Fair Value, Inputs, Level 3 [Member] | Private equity partnerships [Member] | Net Asset Valuation Technique [Member] | Weighted Average or Actual [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | 4.90% | ||
|
Fair Value, Inputs, Level 3 [Member] | Senior secured bank loan funds [Member] | Net Asset Valuation Technique [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 28,537 | ||
|
Fair Value, Inputs, Level 3 [Member] | Senior secured bank loan funds [Member] | Net Asset Valuation Technique [Member] | Low [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | 0.80% | ||
|
Fair Value, Inputs, Level 3 [Member] | Senior secured bank loan funds [Member] | Net Asset Valuation Technique [Member] | Maximum [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | 2.10% | ||
|
Fair Value, 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 | 1.30% | ||
|
Fair Value, Inputs, Level 3 [Member] | Hedge funds [Member] | Net Asset Valuation Technique [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 5,219 | ||
|
Fair Value, Inputs, Level 3 [Member] | Hedge funds [Member] | Net Asset Valuation Technique [Member] | Low [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | 0.00% | ||
|
Fair Value, 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 | 0.00% | ||
|
Fair Value, 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 | 0.00% | ||
|
Fair Value, Inputs, Level 3 [Member] | Other Investments [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 402,206 | ||
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Fair Value, Inputs, Level 3 [Member] | Assumed and ceded reinsurance contracts [Member] | Internal Valuation Model Valuation Technique [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Other assets and (liabilities). fair value | 676 | ||
|
Fair Value, Inputs, Level 3 [Member] | Assumed and ceded reinsurance contracts [Member] | Internal Valuation Model Valuation Technique [Member] | Low [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Net premiums written | 0 | ||
| Contract period | |||
| Reserve for claims and claim expenses | 0 | ||
|
Fair Value, Inputs, Level 3 [Member] | Assumed and ceded reinsurance contracts [Member] | Internal Valuation Model Valuation Technique [Member] | Maximum [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Net premiums written | 0 | ||
| Contract period | |||
| Reserve for claims and claim expenses | 0 | ||
|
Fair Value, Inputs, Level 3 [Member] | Weather and energy related derivatives [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 | 20,000 | ||
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Fair Value, Inputs, Level 3 [Member] | Weather and energy related derivatives [Member] | Spread Option, Quanto, Black Scholes and Simulation Valuation Techniques [Member] | Low [Member]
|
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| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Correlation | 0.00% | ||
| Volatility | 4.00% | ||
| Commodity curve | 3.83 | ||
| Weather curve | 7 | ||
| Counterparty default risk | 0.00% | ||
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Fair Value, Inputs, Level 3 [Member] | Weather and energy related derivatives [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 | 79.00% | ||
| Commodity curve | 93.26 | ||
| Weather curve | 5,427 | ||
| Counterparty default risk | 22.50% | ||
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Fair Value, 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 | 625 | ||
|
Fair Value, Inputs, Level 3 [Member] | Other [Member] | Net Asset Valuation Technique [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Assets, fair value | 22,784 | ||
| Other assets and (liabilities). fair value | $ 22,784 | ||
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Fair Value, Inputs, Level 3 [Member] | Other [Member] | Net Asset Valuation Technique [Member] | Weighted Average or Actual [Member]
|
|||
| Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items] | |||
| Estimated performance | 0.90% | ||