Pension Benefits - Component of net periodic benefit cost (Details) - Pension Plan - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
COMPONENTS OF NET PERIODIC BENEFIT COST:
Service cost	$ 167,000	$ 258,000	$ 417,000	$ 516,000
Interest cost	375,000	435,000	804,000	870,000
Expected return on plan assets	(1,036,000)	(1,034,000)	(2,068,000)	(2,068,000)
Settlement charge	376,000	0	376,000	0
Net periodic pension benefit	$ (118,000)	$ (341,000)	$ (471,000)	$ (682,000)