Stock incentive plans - Options outstanding under company's stock incentive plan (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Options
Options outstanding, beginning of period	0	14
Granted	0	0
Forfeited	0	0
Exercised	0	0
Options outstanding, end of period	0	14
Options exercisable, end of period	0	14
Weighted Average Exercise Price
Options outstanding, beginning of period	$ 0	$ 25.63
Granted	0	0
Forfeited	0	0
Exercised	0	0
Options outstanding, end of period	0	25.28
Fair Value Per Share
Options outstanding, beginning of period	0	9.76
Granted	0	0
Forfeited	0	0
Exercised	0	0
Options outstanding, end of period	$ 0	$ 9.76
Intrinsic Value Options outstanding	$ 0	$ 0