Equity - Summary of Status of Non-Vested Restricted Shares (Supplemental) (Detail) - PVRSU's Outstanding [Member]	12 Months Ended
Dec. 31, 2016 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum number of performance vested shares	0
Target level of performance, percent	50.00%

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.

No definition available.

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