Income taxes (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income taxes
Income tax expense (benefit)	$ 955,000	$ 1,250,000	$ 375,000	$ 1,600,000
Effective income tax rate	27.60%	27.20%	28.90%	27.30%