Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Amortized cost and fair value of fixed maturity securities investments classified by contractual maturity date
Due in 1 year or less, Available for sale, Cost or amortized cost	$ 184,280
Due after 1 year through 5 years, Available for sale, Cost or amortized cost	1,010,609
Due after 5 years through 10 years, Available for sale, Cost or amortized cost	1,427,804
Due after 10 years through 15 years, Available for sale, Cost or amortized cost	993,477
Due after 15 years, Available for sale, Cost or amortized cost	914,686
Securities with contractual maturities, Available for sale, Cost or amortized cost	4,530,856
Mortgage-backed and asset-backed securities, Available for sale, Cost or amortized cost	1,379,182
Available-for-sale fixed maturity Securities, Amortized Cost Basis	5,910,038	5,921,487
Due in 1 year or less, Available for sale, Fair value	188,085
Due after 1 year through 5 years, Available for sale, Fair value	1,056,776
Due after 5 years through 10 years, Available for sale, Fair value	1,497,909
Due after 10 years through 15 years, Available for sale, Fair value	1,029,110
Due after 15 years, Available for sale, Fair value	935,662
Securities with contractual maturities, Available for sale, Fair value	4,707,542
Mortgage-backed and asset-backed securities, Available for sale, Fair value	1,388,084
Available-for-sale Securities, Fixed Maturity Securities, Fair value	$ 6,095,626

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Available For Sale Securities Debt Maturities After Fifteen Years Amortized Cost.

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Available For Sale Securities Debt Maturities After Fifteen Years Fair Value.

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Available For Sale Securities Debt Maturities After Ten Through Fifteen Years Amortized Cost.

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Available For Sale Securities Debt Maturities After Ten Through Fifteen Years Fair Value.

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Available For Sale Securities With Contractual Maturities Amortized Cost.

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Available For Sale Securities With Contractual Maturities Fair Value.

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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