Stock-based compensation - Summary of Stock-based Compensation Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation expense, net of tax	$ 4,485	$ 3,759	$ 4,962
Unit awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation expense, net of tax	3,001	2,490	3,006
Option awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation expense, net of tax	$ 1,484	$ 1,269	$ 1,956