SHARE CAPITAL, OPTION PLANS AND SHARE-BASED PAYMENTS - Non Option Unit Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
Sep. 30, 2023	Jun. 30, 2023
PSUs
Units
Beginning balance (in shares)	1,013,385
Granted (in shares)	612,432
Vested (in shares)	0
Forfeited or expired (in shares)	(24,049)
Ending balance (in shares)	1,601,768	1,013,385
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 61.64
Granted (in dollars per share)	59.22
Vested (in dollars per share)	0
Forfeited or expired (in dollars per share)	61.69
Ending balance (in dollars per share)	$ 60.76	$ 61.64
Weighted- Average Remaining Contractual Term (years)	2 years 1 month 28 days	1 year 9 months
Aggregate Intrinsic Value ($’000's)	$ 56,222	$ 42,106
Restricted Share Units
Units
Beginning balance (in shares)	5,310,595
Granted (in shares)	10,192
Vested (in shares)	(183,094)
Forfeited or expired (in shares)	(106,055)
Ending balance (in shares)	5,031,638	5,310,595
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 36.43
Granted (in dollars per share)	37.51
Vested (in dollars per share)	39.83
Forfeited or expired (in dollars per share)	36.87
Ending balance (in dollars per share)	$ 36.12	$ 36.43
Weighted- Average Remaining Contractual Term (years)	1 year 9 months	1 year 11 months 19 days
Aggregate Intrinsic Value ($’000's)	$ 176,610	$ 220,655
Restricted Share Units \| Long Term Incentive Plan
Units
Beginning balance (in shares)	774,360
Granted (in shares)	466,454
Vested (in shares)	0
Forfeited or expired (in shares)	(24,049)
Ending balance (in shares)	1,216,765	774,360
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 42.83
Granted (in dollars per share)	36.80
Vested (in dollars per share)	0
Forfeited or expired (in dollars per share)	41.83
Ending balance (in dollars per share)	$ 40.55	$ 42.83
Weighted- Average Remaining Contractual Term (years)	2 years 1 month 9 days	1 year 8 months 4 days
Aggregate Intrinsic Value ($’000's)	$ 42,708	$ 32,175
Deferred Share Units (DSUs)
Units
Beginning balance (in shares)	994,568
Granted (in shares)	7,050
Ending balance (in shares)	1,001,618	994,568
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share)	$ 29.98
Granted (in dollars per share)	37.70
Ending balance (in dollars per share)	$ 30.04	$ 29.98
Weighted- Average Remaining Contractual Term (years)	1 month 6 days	4 months 9 days
Aggregate Intrinsic Value ($’000's)	$ 35,157	$ 41,324
Deferred Share Units (DSUs) \| Long Term Incentive Plan
Units
Beginning balance (in shares)	90,906
Ending balance (in shares)	90,906	90,906

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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-Publisher FASB
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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Paragraph 2
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Intrinsic value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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