Available for Sale Securities (Amortized Cost and Estimated Fair Value of Investments Classified as Available for Sale By Contractual Maturity) (Details) $ in Thousands	Sep. 30, 2017 USD ($)
Amortized Cost
Due within one year	$ 345,745
Due after one year through five years	179
Fixed maturities investments excluding mortgage-backed and asset-backed securities	345,924
Mortgage-backed and asset-backed securities	80,967
Amortized Cost	426,891
Estimated Fair Value
Due within one year	345,740
Due after one year through five years	179
Fixed maturities investments excluding mortgage-backed and asset-backed securities	345,919
Mortgage-backed and asset-backed securities	81,223
Total fixed maturities investments, Estimated Fair Value	$ 427,142

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

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

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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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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)
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-Publisher FASB
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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.

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

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