Investments (Securities by Contractual Maturity (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
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	$ 156,470
Due after 1 year through 5 years, Available for sale, Cost or amortized cost	1,117,553
Due after 5 years through 10 years, Available for sale, Cost or amortized cost	1,322,979
Due after 10 years through 15 years, Available for sale, Cost or amortized cost	884,731
Due after 15 years, Available for sale, Cost or amortized cost	1,002,717
Securities with contractual maturities, Available for sale, Cost or amortized cost	4,484,450
Mortgage-backed and asset-backed securities, Available for sale, Cost or amortized cost	1,707,586
Available-for-sale fixed maturity Securities, Amortized Cost Basis	6,192,036	6,352,737
Due in 1 year or less, Available for sale, Fair value	153,783
Due after 1 year through 5 years, Available for sale, Fair value	1,138,249
Due after 5 years through 10 years, Available for sale, Fair value	1,400,954
Due after 10 years through 15 years, Available for sale, Fair value	945,028
Due after 15 years, Available for sale, Fair value	1,060,938
Securities with contractual maturities, Available for sale, Fair value	4,698,952
Mortgage-backed and asset-backed securities, Available for sale, Fair value	1,753,492
Available-for-sale Securities, Fixed Maturity Securities, Fair value	$ 6,452,444	$ 6,610,368

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

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- Definition

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

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- Definition

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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- Definition

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.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

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-Paragraph 1

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Amount after adjustments of available-for-sale debt securities at cost, 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 cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, 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 cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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-Topic 210

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Fair value of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of investment in available-for-sale debt securities with a single maturity date.

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Amount of investment in available-for-sale debt securities with a single maturity date at cost, after adjustments, including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in the statement of income and fair value hedge accounting adjustments.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the next 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 cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of available-for-sale debt securities at cost, net of adjustments, that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the cost over several maturity groupings. 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 that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the fair value over several maturity groupings.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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