XML 150 R111.htm IDEA: XBRL DOCUMENT
v3.25.3

Share-based payments - Disclosure of range of exercise prices, number of options and weighted average remaining contractual life (Details) | 12 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2025 shares $ / shares | Sep. 30, 2024 shares $ / shares | Sep. 30, 2023 shares $ / shares
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Number of options outstanding (in shares) | shares | 2,912,473 | 3,862,527 | 5,211,472
Weighted average remaining contractual life of options outstanding | 2 years 7 months 20 days |  |
Weighted average exercise price of options outstanding (in CAD per share) | $ 77.48 | $ 74.53 | $ 70.21
47.81 to 52.63 |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Number of options outstanding (in shares) | shares | 43,095 |  |
Weighted average remaining contractual life of options outstanding | 7 days |  |
Weighted average exercise price of options outstanding (in CAD per share) | $ 49.10 |  |
47.81 to 52.63 | Minimum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | 47.81 |  |
47.81 to 52.63 | Maximum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | $ 52.63 |  |
57.21 to 63.23 |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Number of options outstanding (in shares) | shares | 1,391,588 |  |
Weighted average remaining contractual life of options outstanding | 1 year 6 months 3 days |  |
Weighted average exercise price of options outstanding (in CAD per share) | $ 63.22 |  |
57.21 to 63.23 | Minimum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | 57.21 |  |
57.21 to 63.23 | Maximum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | $ 63.23 |  |
67.04 to 85.62 |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Number of options outstanding (in shares) | shares | 847,418 |  |
Weighted average remaining contractual life of options outstanding | 2 years 11 months 4 days |  |
Weighted average exercise price of options outstanding (in CAD per share) | $ 84.47 |  |
67.04 to 85.62 | Minimum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | 67.04 |  |
67.04 to 85.62 | Maximum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | $ 85.62 |  |
97.84 to 110.73 |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Number of options outstanding (in shares) | shares | 630,372 |  |
Weighted average remaining contractual life of options outstanding | 4 years 11 months 4 days |  |
Weighted average exercise price of options outstanding (in CAD per share) | $ 101.50 |  |
97.84 to 110.73 | Minimum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | 97.84 |  |
97.84 to 110.73 | Maximum |  |  |
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items] |  |  |
Exercise price (in CAD per share) | $ 110.73 |  |

X
- 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
Name: | ifrs-full_DisclosureOfNumberAndWeightedAverageRemainingContractualLifeOfOutstandingShareOptionsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The exercise price of outstanding share options. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph d -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_d&doctype=Standard -URIDate 2025-03-27 + Details
Name: | ifrs-full_ExercisePriceOfOutstandingShareOptions2019
Namespace Prefix: | ifrs-full_
Data Type: | dtr-2022:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of share options outstanding in a share-based payment arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph d -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_d&doctype=Standard -URIDate 2025-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_i&doctype=Standard -URIDate 2025-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph b -Clause vi -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_vi&doctype=Standard -URIDate 2025-03-27 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_i&doctype=Standard -URIDate 2025-03-27 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause vi -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_vi&doctype=Standard -URIDate 2025-03-27 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause vi -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_vi&doctype=Standard -URIDate 2025-03-27 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_i&doctype=Standard -URIDate 2025-03-27 + Details
Name: | ifrs-full_NumberOfOutstandingShareOptions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition The weighted average exercise price of share options outstanding in a share-based payment arrangement. [Refer: Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_i&doctype=Standard -URIDate 2025-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph b -Clause vi -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_vi&doctype=Standard -URIDate 2025-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause vi -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_vi&doctype=Standard -URIDate 2025-03-27 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_i&doctype=Standard -URIDate 2025-03-27 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_i&doctype=Standard -URIDate 2025-03-27 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2027-01-01 -Name IFRS -Number 19 -IssueDate 2025-01-01 -Paragraph 31 -Subparagraph b -Clause vi -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_vi&doctype=Standard -URIDate 2025-03-27 + Details
Name: | ifrs-full_WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019
Namespace Prefix: | ifrs-full_
Data Type: | dtr-2022:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The weighted average remaining contractual life of outstanding share options. [Refer: Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2025-01-01 -Paragraph 45 -Subparagraph d -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_d&doctype=Standard -URIDate 2025-03-27 + Details
Name: | ifrs-full_WeightedAverageRemainingContractualLifeOfOutstandingShareOptions2019
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=gib_ExercisePriceRangeOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=gib_ExercisePriceRangeTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=gib_ExercisePriceRangeThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=gib_ExercisePriceRangeFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |