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Fair Value Of Financial Instruments (Tables) | 6 Months Ended
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Jun. 30, 2012
Financial Instruments, Owned, at Fair Value [Abstract] |
Estimated Fair Values Of Financial Instruments | The following table presents the estimated fair values of financial instruments at June 30, 2012 and December 31, 2011.
| June 30, 2012 |  | December 31, 2011
| (Amounts in thousands)
Assets |  |  |
Investments | $ | 3,113,130 |  |  | $ | 3,062,421 |
Liabilities |  |  |
Interest rate swap agreements | $ | 399 |  |  | $ | 670 |
Equity contracts | $ | 643 |  |  | $ | 655 |
Secured notes payable | $ | 140,000 |  |  | $ | 140,000 |

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