Pension and Other Postretirement Benefits (Details) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2023	Mar. 31, 2023	Mar. 31, 2022
Pension and other postretirement benefits expenses
Increase in stockholders equity	$ 11,324
Pensions
Pension and other postretirement benefits expenses
Service cost		$ 773,000	$ 1,555,000
Interest cost		4,895,000	3,434,000
Expected return on plan assets		(7,534,000)	(7,281,000)
Amortization of prior service cost		87,000	108,000
Amortization of actuarial losses		417,000	3,139,000
Special termination benefits		0	136,000
Net periodic benefit (income) cost		(1,362,000)	1,091,000
Other Postretirement Benefits
Pension and other postretirement benefits expenses
Service cost		13,000	24,000
Interest cost		285,000	206,000
Amortization of prior service cost		3,000	0
Amortization of actuarial losses		(25,000)	9,000
Net periodic benefit (income) cost		$ 276,000	$ 239,000