Investments (Details 16) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Mortgage Loans:
Total mortgage loans	$ 2,335,115,000	$ 2,312,167,000
Mortgage Loans Net Of Valuation Allowances [Abstract]
Mortgage loans on real estate	2,325,191,000	2,300,587,000
Commercial Real Estate Portfolio Segment Member
Mortgage Loans:
Evaluated individually for credit losses	41,167,000	39,956,000
Evaluated collectively for credit losses	2,293,948,000	2,272,211,000
Total mortgage loans	2,335,115,000	2,312,167,000
Valuation Allowances:
Specific for credit losses	6,008,000	6,980,000
Non-specifically identified credit losses	3,916,000	4,600,000
Total valuation allowances	$ 9,924,000	$ 11,580,000

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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The valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Reflects the sum of the gross carrying amounts of unpaid loans issued to businesses to acquire, develop, construct, improve, or refinance land or a building. Includes [but is not limited to] commercial mortgage loans, which are secured by a [legal] security interest in real property [commercial building or business real property] which thereby serves as collateral securing repayment of the loan; and construction financing, which is an obligation generally in the form of a [promissory] note, used for the funding of construction projects.

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