Available For Sale Securities (Amortized Cost And Estimated Fair Value Of Investments Classified As Available For Sale By Contractual Maturity) (Details) $ in Thousands	Mar. 31, 2017 USD ($)
Schedule of Investments [Line Items]
Due within one year, Amortized Cost	$ 293,286
Due after one year through five years, Amortized Cost	179
Fixed maturities investments excluding mortgage-backed and asset-backed securities, Amortized Cost	293,465
Mortgage-backed and asset-backed securities, Amortized Cost	73,329
Amortized Cost	366,794
Due within one year, Estimated Fair Value	293,142
Due after one year through five years, Estimated Fair Value	179
Fixed maturities investments excluding mortgage-backed and asset-backed securities, Estimated Fair Value	293,321
Mortgage-backed and asset-backed securities, Estimated Fair Value	73,637
Total fixed maturities investments, Estimated Fair Value	$ 366,958

Available-For-Sale Securities Debt Maturities Due within One Year, Amortized Cost Basis

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- Definition

Available-For-Sale Securities Debt Maturities Due within One Year, Fair Value

+ References

No definition available.

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Fixed maturities investments excluding mortgage-backed and asset-backed securities, amortized cost.

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Fixed maturities investments excluding mortgage-backed and asset-backed securities, estimated fair value.

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No definition available.

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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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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SX 210.5-02.2)
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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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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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