Employee compensation plans - Schedule of Stock Compensation Assumptions Used (Details) - Stock Appreciation Rights (SARs)	12 Months Ended
	Dec. 31, 2022 USD ($)
January 5, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	5 days
Expected volatility factor (as a percent)	12.966%
Risk-free interest rate (as a percent)	0.513%
Quarterly dividends (in dollars per share)	$ 0.6
January 11, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	1 year
Expected volatility factor (as a percent)	37.031%
Risk-free interest rate (as a percent)	4.68%
Quarterly dividends (in dollars per share)	$ 0.6
January 10, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	2 years
Expected volatility factor (as a percent)	36.412%
Risk-free interest rate (as a percent)	4.421%
Quarterly dividends (in dollars per share)	$ 0.6
January 11, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	3 years
Expected volatility factor (as a percent)	43.974%
Risk-free interest rate (as a percent)	4.221%
Quarterly dividends (in dollars per share)	$ 0.6
January 7, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	4 years
Expected volatility factor (as a percent)	39.848%
Risk-free interest rate (as a percent)	4.112%
Quarterly dividends (in dollars per share)	$ 0.6