Basis of Presentation - Additional Information (Detail)	12 Months Ended
Dec. 31, 2020
Ontario Inc. 2435572 [Member]
Disclosure of basis of preparation [Line Items]
Proportion of ownership interest in subsidiary	100.00%
Ontario Inc 2435386 [Member]
Disclosure of basis of preparation [Line Items]
Proportion of ownership interest in subsidiary	100.00%
Ontario Inc 2435386 [Member] \| Gk mine [Member]
Disclosure of basis of preparation [Line Items]
Proportion of ownership interest in associate	49.00%
Kennady Diamonds Inc [Member]
Disclosure of basis of preparation [Line Items]
Proportion of ownership interest in subsidiary	100.00%

The proportion of ownership interest in an associate attributable to the entity. [Refer: Associates [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2020-01-01
-Paragraph 17
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_17_b_iii&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2020-01-01
-Paragraph 16
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2020-en-r&anchor=para_16_b_iii&doctype=Standard
-URIDate 2020-01-01

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2020-01-01
-Paragraph 21
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_21_a_iv&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_ProportionOfOwnershipInterestInAssociate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration