Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2024	Dec. 31, 2023
Uranium [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Royalty payable on revenue percentage	20.00%
Thacker Pass [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Prepayments on housing units	$ 6,860	$ 15,315
Royalty Claims [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Capital commitments	$ 22,000
Royalty payable on revenue percentage	8.00%
Royalty payable on revenue for life of project percentage	4.00%
Royalty payable on revenue upon payment of commitment percentage	1.75%

The amount of future capital expenditures that the entity is committed to make.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of non-current prepayments. [Refer: Prepayments]

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 78
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2024-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Royalty Payable On Revenue For life Of Project Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	lac_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Royalty Payable On Revenue Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	lac_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Royalty Payable On Revenue Upon Payment Of Commitment Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	lac_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=lac_ThackerPassProjectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: