Investments (Mortgage Loans by Method of Evaluation and Related Valuation Allowances) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Mortgage Loans:
Total mortgage loans	$ 2,534,694	$ 2,496,786
Mortgage Loans Net Of Valuation Allowances [Abstract]
Mortgage loans on real estate (net of valuation allowances)	2,526,228	2,486,680
Commercial Real Estate Portfolio Segment
Mortgage Loans:
Evaluated individually for credit losses	32,344	37,841
Evaluated collectively for credit losses	2,502,350	2,458,945
Total mortgage loans	2,534,694	2,496,786
Valuation Allowances:
Specific for credit losses	1,677	3,211
Non-specifically identified credit losses	6,789	6,895
Total valuation allowances	$ 8,466	$ 10,106

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

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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