Income taxes (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income taxes
Income tax expense (benefit)	$ 95,000	$ 590,000	$ (105,000)	$ 965,000
Effective income tax rate	21.70%	31.80%	9.70%	30.60%