Pension and Retirement Plans - Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Pension Plan
Net periodic benefit cost (credit)
Interest cost	$ 452	$ 310
Expected return on assets	(801)	(936)
Net periodic benefit cost (credit)	(349)	(626)
Supplemental Retirement Plan
Net periodic benefit cost (credit)
Service cost	68	101
Interest cost	100	59
Net periodic benefit cost (credit)	168	160
Postretirement Healthcare Plan
Net periodic benefit cost (credit)
Service cost	4	8
Interest cost	5	5
Amortization of net actuarial (gain) loss	(6)
Net periodic benefit cost (credit)	$ 3	$ 13