Fair Value Disclosures (Details 1) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	$ (243,177,000)	$ (361,456,000)
Fair Value Assets Measured On Recurring Basis Reinsurance Ceded Receivable Embedded Derivatives	0	4,945,000
Discounted Cash Flow [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives	740,256,000
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives	172,105,000
Discounted Cash Flow [Member] | Mortality [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	0.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	0.00%
Discounted Cash Flow [Member] | Mortality [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	100.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	100.00%
Discounted Cash Flow [Member] | Mortality [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	1.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	1.00%
Discounted Cash Flow [Member] | Lapse [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	0.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	0.00%
Discounted Cash Flow [Member] | Lapse [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	35.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	25.00%
Discounted Cash Flow [Member] | Lapse [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	4.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	5.00%
Discounted Cash Flow [Member] | Withdrawal [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	0.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	0.00%
Discounted Cash Flow [Member] | Withdrawal [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	5.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	7.00%
Discounted Cash Flow [Member] | Withdrawal [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	4.00%
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	4.00%
Discounted Cash Flow [Member] | Own Credit [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	0.00%
Discounted Cash Flow [Member] | Own Credit [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	1.00%
Discounted Cash Flow [Member] | Own Credit [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	1.00%
Discounted Cash Flow [Member] | Option Budget Projection [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	2.00%
Discounted Cash Flow [Member] | Option Budget Projection [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	4.00%
Discounted Cash Flow [Member] | Option Budget Projection [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Indexed Annuities Embedded Derivatives Unobservable Input Range	3.00%
Discounted Cash Flow [Member] | Long Term Volatility [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	0.00%
Discounted Cash Flow [Member] | Long Term Volatility [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	27.00%
Discounted Cash Flow [Member] | Long Term Volatility [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Liabilities Measured On Recurring Basis Guaranteed Interest Contracts Variable Annuities Embedded Derivatives Unobservable Input Range	16.00%
Total Return Swap [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	(243,177,000)
Total Return Swap [Member] | Mortality [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	0.00%
Total Return Swap [Member] | Mortality [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	100.00%
Total Return Swap [Member] | Mortality [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	1.00%
Total Return Swap [Member] | Lapse [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	0.00%
Total Return Swap [Member] | Lapse [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	35.00%
Total Return Swap [Member] | Lapse [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	4.00%
Total Return Swap [Member] | Withdrawal [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	0.00%
Total Return Swap [Member] | Withdrawal [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	5.00%
Total Return Swap [Member] | Withdrawal [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	4.00%
Total Return Swap [Member] | Own Credit [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	0.00%
Total Return Swap [Member] | Own Credit [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	1.00%
Total Return Swap [Member] | Own Credit [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	1.00%
Total Return Swap [Member] | Crediting Rate [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	2.00%
Total Return Swap [Member] | Crediting Rate [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	4.00%
Total Return Swap [Member] | Crediting Rate [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
Fair Value Assets Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives Unobservable Input Range	3.00%
Market Comparable Securities [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
State And Political Subdivision Securities	5,451,000
Corporate Securities	450,177,000
ShortTermInvestments	$ 22,031,000
Market Comparable Securities [Member] | Liquidity Premium [Member] | Minimum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
State And Political Subdivision Securities Unobservable Input Range	1.00%
Corporate Securities Unobservable Input Range	0.00%
Short Term Investments Unobservable Input Range	1.00%
Market Comparable Securities [Member] | Liquidity Premium [Member] | Maximum [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
State And Political Subdivision Securities Unobservable Input Range	1.00%
Corporate Securities Unobservable Input Range	2.00%
Short Term Investments Unobservable Input Range	1.00%
Market Comparable Securities [Member] | Liquidity Premium [Member] | Weighted Average [Member]
Unobservable Inputs Used In Level3 Fair Value Measurements [Line Items]
State And Political Subdivision Securities Unobservable Input Range	1.00%
Corporate Securities Unobservable Input Range	1.00%
Short Term Investments Unobservable Input Range	1.00%