Incentive Plans - Schedule of Activity Relating to RSUs and DSUs (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2020 shares
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend participation rights	608,328

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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration