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Investments - Additional Information (Detail) | 6 Months Ended
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Sep. 30, 2018
Minimum [Member] |
Schedule of Held-to-maturity Securities [Line Items] |
Treasury with original maturities period | 3 months
Maximum [Member] |
Schedule of Held-to-maturity Securities [Line Items] |
Investment maturity date range end | May 02, 2019
Treasury with original maturities period | 1 year

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- Definition Original maturity period for held to maturity securities. + References No definition available. + Details
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Balance Type: | na
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- Definition The maturity date of the investment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 12 -Sentence Column A + Details
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- Definition 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. + References No definition available. + Details
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- Details
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- Details
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