Fair Value of Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investments
Other investments, Carrying Value	$ 6,292,097	$ 5,677,508
Financial Liabilities
Fixed annuity contract liabilities	3,257,758	2,945,107
Fixed annuity contract liabilities, Fair value	3,070,111	2,699,295
Policyholder account balances on interest-sensitive life contracts	79,017	79,305
Policyholder account balances on interest-sensitive life contracts, Fair value	78,519	76,370
Other policyholder funds	103,227	114,530
Other policyholder funds, Fair Value	103,227	114,530
Short-term debt	38,000	38,000
Short-term debt, Fair Value	38,000	38,000
Long-term debt	199,809	199,744
Long-term debt, Fair Value	219,319	214,218
Other investments [Member]
Investments
Other investments, Carrying Value	134,985	128,460
Other investments, Fair Value	135,121	132,522
Level 1 [Member]
Financial Liabilities
Long-term debt, Fair Value	219,319	214,218
Level 2 [Member]
Financial Liabilities
Short-term debt, Fair Value	38,000	38,000
Level 3 [Member]
Financial Liabilities
Fixed annuity contract liabilities, Fair value	3,070,111	2,699,295
Policyholder account balances on interest-sensitive life contracts, Fair value	78,519	76,370
Other policyholder funds, Fair Value	103,227	114,530
Level 3 [Member] \| Other investments [Member]
Investments
Other investments, Fair Value	$ 135,121	$ 132,522

Liability for future policy benefits individual and group annuities and supplementary contracts fair value disclosure.

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- Definition

Liability for policy holder account balances life.

+ References

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- Definition

Liability for policyholder account balances life fair value.

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- Definition

Fair Value of the liability as of the balance sheet date to the policyholders for funds held that are returnable under the terms of insurance contracts that were not separately reported.

+ References

No definition available.

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- Definition

Sum of the carrying amounts as of the balance sheet date of all investments.

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents investment securities as of the balance sheet date which may include marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

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-Name Accounting Standards Codification

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The accrued obligation to policyholders that relates to individual and group annuities and supplementary contracts insured events, and can be viewed as either (a) the present value of future benefits to be paid to or on behalf of policyholders and expenses less the present value of future net premiums payable under the insurance contracts or (b) the accumulated amount of net premiums already collected less the accumulated amount of benefits and expenses already paid to or on behalf of policyholders.

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-Name Regulation S-X (SX)

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

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- Definition

Liability as of the balance sheet date to the policyholders for funds held that are returnable under the terms of insurance contracts that were not separately reported.

+ References

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- Definition

Carrying amount at the balance sheet date of borrowings from a bank, not elsewhere enumerated in the taxonomy, with a maturity within one year (or within one operating cycle if longer) from the date of borrowing.

+ References

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

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