Investments (Investments Classified by Contractual Maturity Date) (Details) - Fixed Income Securities	Sep. 30, 2018 USD ($)
Debt Securities, Available-for-sale [Line Items]
Due within one year	$ 141,685,968
Due between one and five years	129,595,580
Due over five years	8,795,930
Total	$ 280,077,478

No definition available.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), maturing in next fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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