Goodwill - Changes in Carrying Amount of Goodwill (Details) - CAD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Mar. 31, 2022
Goodwill [Line Items]
Beginning Balance		$ 1,866,503	$ 1,889,354
Purchase accounting allocations			105,323
Disposal of consolidated entities	$ (227)	(227)
Impairment losses	(2,311)	(1,727,679)	(40,748)
Foreign currency translation adjustments		(2,084)	(28,640)
Ending Balance	$ 136,513	$ 136,513	1,866,503
Consolidated Entities
Goodwill [Line Items]
Disposal of consolidated entities			$ (58,786)