Stock-based compensation - Summary of incentive plan for members of the Board of Directors (Details) - Directors - $ / shares	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward
Non-vested at beginning of period			0	0	0
Granted			37,712		25,321
Vested			(37,712)		(25,321)
Forfeited			0		0
Non-vested at end of period	0		0		0
Weighted-Average Grant Date Fair Value
Non-vested at beginning of period			$ 0	$ 0	$ 0
Granted			55.05		77.48
Vested			55.05		77.48
Forfeited			0		0
Non-vested at end of period	$ 0		$ 0		$ 0
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward
Granted	1,384	857	35,412	24,409