LEASES - Schedule of Undiscounted Lease Payments to be Received Under Finance Leases (Details) - CAD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	$ 202.8	$ 235.4
Unearned finance income	(65.2)	(71.4)
Discounted unguaranteed residual values of leased assets	(9.1)	(9.0)
Total investment in finance leases	128.5	155.0
Current portion (Note 12)	13.6	16.8
Non-current portion (Note 18)	114.9	138.2
Less than 1 year
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	17.2	19.5
Between 1 and 2 years
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	17.2	19.8
Between 2 and 3 years
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	20.6	27.4
Between 3 and 4 years
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	10.6	10.3
Between 4 and 5 years
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	12.4	11.6
More than 5 years
Disclosure of maturity analysis of finance lease payments receivable [line items]
Total undiscounted lease payments receivable	$ 124.8	$ 146.8

The amount of current finance lease receivables. [Refer: Finance lease receivables]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

The amount of the discounted unguaranteed residual value of assets subject to finance leases. Unguaranteed residual value is the portion of the residual value of the underlying asset, the realisation of which by a lessor is not assured or is guaranteed solely by a party related to the lessor. Finance lease is a lease that transfers substantially all the risks and rewards incidental to ownership of an underlying asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 94
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_94&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

The gross investment in the finance lease discounted at the interest rate implicit in the lease. Finance lease is a lease that transfers substantially all the risks and rewards incidental to ownership of an underlying asset. Gross investment in the finance lease is the sum of: (a) the lease payments receivable by a lessor under a finance lease; and (b) any unguaranteed residual value accruing to the lessor. Interest rate implicit in the lease is the rate of interest that causes the present value of (a) the lease payments and (b) the unguaranteed residual value to equal to the sum of (i) the fair value of the underlying asset and (ii) the initial direct costs of the lessor.

+ References

+ Details

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

- Definition

The amount of non-current finance lease receivables. [Refer: Finance lease receivables]

+ References

+ Details

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

- Definition

The amount of undiscounted finance lease payments to be received. Finance lease is a lease that transfers substantially all the risks and rewards incidental to ownership of an underlying asset.

+ References

+ Details

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

- Definition

The amount of unearned finance income relating to the finance lease payments receivable. Finance lease is a lease that transfers substantially all the risks and rewards incidental to ownership of an underlying asset. [Refer: Finance income]

+ References

+ Details

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

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_NotLaterThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanOneYearAndNotLaterThanTwoYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanTwoYearsAndNotLaterThanThreeYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanThreeYearsAndNotLaterThanFourYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanFourYearsAndNotLaterThanFiveYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanFiveYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: