Financial instruments (Measurement of fair values) (Details) - CAD ($)	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financial assets [Abstract]
Cash and cash equivalents	$ 1,143,674,000	$ 1,247,447,000	$ 918,382,000
Short-term investments	1,138,174,000	84,906,000
Derivative assets	2,807,000	32,098,000
Accounts receivable	183,944,000	276,139,000
Investments in equity securities	29,585,000	0
Financial assets	2,468,599,000	1,640,590,000
Financial liabilities [Abstract]
Accounts payable and accrued liabilities	374,714,000	340,458,000
Lease obligation	9,287,000	4,872,000
Derivative liabilities	58,342,000	4,997,000
Long-term debt	997,000,000	996,250,000
Financial liabilities	1,439,343,000	1,346,577,000
Net	1,029,256,000	294,013,000
Foreign currency contracts [Member]
Financial assets [Abstract]
Derivative assets	2,807,000	31,534,000
Financial liabilities [Abstract]
Derivative liabilities	51,058,000	3,760,000
Interest rate contracts [Member]
Financial assets [Abstract]
Derivative assets		564,000
Financial liabilities [Abstract]
Derivative liabilities	7,284,000	1,237,000
Fair value through profit or loss [member]
Financial liabilities [Abstract]
Accounts payable and accrued liabilities	0	0
Lease obligation	0	0
Long-term debt	0	0
Financial liabilities	58,342,000	4,997,000
Net	(55,535,000)	27,101,000
Fair value through profit or loss [member] \| Foreign currency contracts [Member]
Financial liabilities [Abstract]
Derivative liabilities	51,058,000	3,760,000
Fair value through profit or loss [member] \| Interest rate contracts [Member]
Financial liabilities [Abstract]
Derivative liabilities	7,284,000	1,237,000
Financial liabilities at amortised cost category [Member]
Financial liabilities [Abstract]
Accounts payable and accrued liabilities	374,714,000	340,458,000
Lease obligation	9,287,000	4,872,000
Long-term debt	997,000,000	996,250,000
Financial liabilities	1,381,001,000	1,341,580,000
Net	1,084,791,000	266,912,000
Financial liabilities at amortised cost category [Member] \| Foreign currency contracts [Member]
Financial liabilities [Abstract]
Derivative liabilities	0	0
Financial liabilities at amortised cost category [Member] \| Interest rate contracts [Member]
Financial liabilities [Abstract]
Derivative liabilities	0	0
Fair value through profit or loss [member]
Financial assets [Abstract]
Cash and cash equivalents	0	0
Short-term investments	0	0
Accounts receivable	0	0
Financial assets	2,807,000	32,098,000
Fair value through profit or loss [member] \| Foreign currency contracts [Member]
Financial assets [Abstract]
Derivative assets	2,807,000	31,534,000
Fair value through profit or loss [member] \| Interest rate contracts [Member]
Financial assets [Abstract]
Derivative assets		564,000
Financial assets at amortised cost category [Member]
Financial assets [Abstract]
Cash and cash equivalents	1,143,674,000	1,247,447,000
Short-term investments	1,138,174,000	84,906,000
Accounts receivable	183,944,000	276,139,000
Financial assets	2,465,792,000	1,608,492,000
Financial liabilities [Abstract]
Net	1,084,791,000	266,912,000
Financial assets at amortised cost category [Member] \| Foreign currency contracts [Member]
Financial assets [Abstract]
Derivative assets	$ 0	0
Financial assets at amortised cost category [Member] \| Interest rate contracts [Member]
Financial assets [Abstract]
Derivative assets		$ 0

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The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]

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The amount of financial assets classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

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The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

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The amount of investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: At fair value [member]; Other comprehensive income]

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The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

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The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

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The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration.

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The amount of current trade payables and current other payables. [Refer: Current trade payables; Other current payables]

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