Investments (Amortized Cost And Estimated Fair Value Of Non-Current Investments Classified As Available For Sale By Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012
Investments [Abstract]
Due after one year through five years, Amortized Cost	$ 30,380
Due after five years through ten years, Amortized Cost
Due after ten years, Amortized Cost
Non-current fixed maturities investments excluding mortgage-backed and asset-back securities, Amortized Cost	30,380
Mortgage-backed and asset-backed securities, Amortized Cost	646,268
Total non-current fixed maturities investments, Amortized Cost	676,648
Due after one year through five years, Estimated Fair Value	30,611
Due after five years through ten years, Estimated Fair Value
Due after ten years, Estimated Fair Value
Non-current fixed maturities investments excluding mortgage-backed and asset-back securities, Estimated Fair Value	30,611
Mortgage-backed and asset-backed securities, Estimated Fair Value	660,479
Total non-current fixed maturities investments, Estimated Fair Value	$ 691,090

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Debt Securities Available For Sale Securities Estimated Fair Value

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Mortgage backed and asset backed securities amortized cost.

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Mortgage Backed And Asset Backed Securities Estimated Fair Value

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Non-current fixed maturities investments excluding mortgage - backed and assets backed securities, amortized cost.

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Non-current fixed maturities investments excluding mortgage - backed and assets backed securities, estimated fair value.

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

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This item represents the fair value of debt securities which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 20

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

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-Name FASB Staff Position (FSP)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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