Stock-based compensation - Summary of Deferred Share Units Plan (Details) - DSUs - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] (in shares)
Outstanding, January 1 (in shares)	841,333	774,053
Granted (in shares)	60,262	70,112
Units, in lieu of dividends (in shares)	6,510	6,753
Settled (in shares)	(162,319)	(6,677)
Forfeited (in shares)	(1,256)	(2,908)
Outstanding, December 31 (in shares)	744,530	841,333