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Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Detail) | 12 Months Ended
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Dec. 31, 2016
Fair Value, Measurements, Recurring |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
Redeemable shares, settlement period | 3 days

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- Definition Share Settlement Period + References No definition available. + Details
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Balance Type: | na
Period Type: | duration

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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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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |