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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, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Investments [Abstract]
Balance, beginning of year	$ 6,602	$ 17,723	$ 22,189
Credit losses remaining in retained earnings after adoption of OTTI accounting guidance	0	0	0
Addition for the amount related to credit loss for which an OTTI was not previously recognized	0	0	2,326
Reductions for securities sold during the period	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
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	(11,672)	(8,143)
Additional increases to the amount related to credit loss for which an OTTI was previously recognized	875	551	4,341
Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	0	0	0
Balance, end of year	$ 7,477	$ 6,602	$ 17,723

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- Definition

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Credit losses remaining in retained earnings after adoption of OTTI accounting guidance.

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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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