Retirement plans - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Retirement plans
Percentage of employee contribution of eligible compensation plan			50.00%
Employer match percentage			50.00%
Percent of employee contributions eligible for employer match			6.00%
Employer match expense	$ 884	$ 609	$ 2,631	$ 2,585