CONTRACTS IN PROGRESS (Details) - CAD ($) $ in Millions	12 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Recognised Revenue From Construction Contracts [Abstract]
Contracts in progress: assets	$ 401.6	$ 337.5
Contracts in progress: liabilities	(161.8)	(191.9)
Contracts in progress: net assets	239.8	145.6
Aggregate amount of costs incurred plus recognized profits (less recognized losses) to date	2,694.6	2,800.1
Less: progress billings	2,454.8	2,654.5
Advances received for contracts in progress	15.1	20.2
Revenue from construction contracts	$ 851.7	$ 983.6

Net Amount Due From Customers For Contract Work As Asset

No definition available.

Name:	cae_NetAmountDueFromCustomersForContractWorkAsAsset
Namespace Prefix:	cae_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recognised Revenue From Construction Contracts

+ References

No definition available.

+ Details

Name:	cae_RecognisedRevenueFromConstructionContractsAbstract
Namespace Prefix:	cae_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of advances received by the entity before the related work is performed on construction contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Paragraph 40
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=para_40_b&doctype=Standard&book=B
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRIC
-Number 15
-IssueDate 2017-01-01
-Paragraph 21
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRIC&num=15&date=2017-03-02&anchor=para_21_b&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

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

- Definition

The aggregate amount of costs incurred and recognised profits, less recognised losses, to date on construction contracts in progress.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Paragraph 40
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=para_40_a&doctype=Standard&book=B
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRIC
-Number 15
-IssueDate 2017-01-01
-Paragraph 21
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRIC&num=15&date=2017-03-02&anchor=para_21_a&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_CostsIncurredAndRecognisedProfitsLessRecognisedLosses
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount recognised as an asset as the net of: (a) costs incurred plus recognised profits; less (b) the sum of recognised losses and progress billings for all contracts in progress for which costs incurred plus recognised profits (less recognised losses) exceeds progress billings.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Paragraph 42
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=para_42_a&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

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

- Definition

The amount recognised as a liability as the net of: (a) costs incurred plus recognised profits; less (b) the sum of recognised losses and progress billings for all contracts in progress for which progress billings exceed costs incurred plus recognised profits (less recognised losses).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Paragraph 42
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=para_42_b&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

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

- Definition

The amounts billed for work performed on a construction contract whether or not they have been paid by the customer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Section Contract disclosures
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=sect_Contractdisclosures&doctype=Illustrative%20Examples&book=B
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Paragraph 41
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=para_41&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_ProgressBillings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of revenue arising from construction contracts. Construction contracts are contracts specifically negotiated for the construction of an asset or a combination of assets that are closely interrelated or interdependent in terms of their design, technology and function or their ultimate purpose or use. [Refer: Revenue]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 11
-IssueDate 2017-01-01
-Paragraph 39
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=11&date=2017-03-02&anchor=para_39_a&doctype=Standard&book=B
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 18
-IssueDate 2017-01-01
-Paragraph 35
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=18&date=2017-03-02&anchor=para_35_b&doctype=Standard&book=B
-URIDate 2017-03-09

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2017-03-09

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRIC
-Number 15
-IssueDate 2017-01-01
-Paragraph 20
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRIC&num=15&date=2017-03-02&anchor=para_20_b&doctype=Standard&book=B
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_RevenueFromConstructionContracts
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration