Employee Benefit Plans - Schedule of beginning and ending balances of accumulated postretirement benefit obligations (Details) - Other Postretirement Benefit Plans - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Benefit Plans
Accumulated postretirement benefit obligations at the beginning of the year	$ 4,062,000	$ 5,865,000
Interest Cost	192,000	157,000
Actuarial loss/(gain)	152,000	(1,838,000)
Benefits paid	(144,000)	(122,000)
Accumulated postretirement benefit obligations at the end of the year	$ 4,262,000	$ 4,062,000