Fair Value of Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Investments
Other investments, Carrying Amount	$ 6,426,099	$ 6,292,097
Financial Liabilities
Fixed annuity contract liabilities	3,311,013	3,257,758
Fixed annuity contract liabilities, Fair value	3,119,794	3,070,111
Policyholder account balances on interest-sensitive life contracts	78,902	79,017
Policyholder account balances on interest-sensitive life contracts, Fair value	78,404	78,519
Other policyholder funds	101,032	103,227
Other policyholder funds, Fair Value	101,032	103,227
Short-term debt	38,000	38,000
Short-term debt, Fair Value	38,000	38,000
Long-term debt	199,825	199,809
Long-term debt, Fair Value	221,712	219,319
Other liabilities, repurchase agreement obligations, Carrying value and Fair value	87,846
Other investments [Member]
Investments
Other investments, Carrying Amount	135,653	134,985
Other investments, Fair Value	137,393	135,121
Level 1 [Member]
Financial Liabilities
Long-term debt, Fair Value	221,712	219,319
Level 2 [Member]
Financial Liabilities
Short-term debt, Fair Value	38,000	38,000
Other liabilities, repurchase agreement obligations, Carrying value and Fair value	87,846
Level 3 [Member]
Financial Liabilities
Fixed annuity contract liabilities, Fair value	3,119,794	3,070,111
Policyholder account balances on interest-sensitive life contracts, Fair value	78,404	78,519
Other policyholder funds, Fair Value	101,032	103,227
Level 3 [Member] \| Other investments [Member]
Investments
Other investments, Fair Value	$ 137,393	$ 135,121

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

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Liability for policy holder account balances life.

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Liability for policyholder account balances life fair value.

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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.

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

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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.

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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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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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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.

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The carrying value as of the balance sheet date of securities that an institution sells and agrees to repurchase (the identical or substantially the same securities) as a seller-borrower at a specified date for a specified price, also known as a repurchase agreement, or repo. Most repos involve obligations of the federal government or its agencies, but other financial instruments, such as commercial paper, banker's acceptances, and negotiable certificates of deposit, are sometimes used in repos.

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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.

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