Income taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Federal statutory rate (as a percent)	21.00%	21.00%
State and local income taxes, net of federal benefit (as a percent)	13.40%	(0.50%)
Foreign operations (as a percent)	(6.40%)	15.10%
Permanent items (as a percent)	(8.10%)	3.10%
Deferred adjustments (as a percent)	0.00%	16.80%
Others (as a percent)	4.10%	2.70%
Effective tax rate (as a percent)	24.00%	58.20%