Investments (Gross Credit Loss Impairments of Fixed Maturity Securities for Which a Portion of the OTTI Charge was Recognized in OCI) (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Investments [Abstract]
Balance, beginning of period	$ 14,024	$ 20,343	$ 17,723	$ 22,189
Addition for the amount related to credit loss for which an OTTI was not previously recognized	0	192	0	2,326
Reductions for securities sold during the period	0	0	0	(2,990)
Reductions for securities for which the amount previously recognized in OCI was recognized in earnings because of intention or potential requirement to sell before recovery of amortized cost	0	0	0	0
Reductions for securities for which the entire amount previously recognized in OCI was recognized in earnings due to a decrease in cash flows expected	0	(3,254)	(3,954)	(7,906)
Additional increases to the amount related to credit loss for which an OTTI was previously recognized	207	530	462	4,192
Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	0	0	0	0
Balance, end of period	$ 14,231	$ 17,811	$ 14,231	$ 17,811

This item represents accretion of credit loss impairments previously recognized due to an increase in cash flow expected to be collected on securities for which an other-than-temporary impairment charge was recognized in other comprehensive income.

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This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis.

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This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which no such other than temporary impairment (OTTI) was previously recognized.

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The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

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This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held due to increases in cash flows expected to be collected and recognized over the remaining life of the security.

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This item represents reductions in the amount of cumulative losses recognized in earnings for other than temporary impairments (OTTI) for which a portion of the impairment had been recognized in other comprehensive income (a component of shareholders' equity) due to a change in status of the impaired security because of a change in the entity's intent to either sell the impaired security or it has become more likely than not that the entity will be required to sell the security before recovery of its cost basis.

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This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of impaired securities during the period.

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