Postretirement Benefits - Pension Plan Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Retirement Benefits [Abstract]
Service cost for benefits earned	$ 8,651	$ 7,191
Interest cost on benefit obligation	13,145	12,548
Expected return on plan assets	(20,198)	(17,218)
Prior service cost amortization	389	362
Net actuarial gain amortization	(1,751)	(3,833)
Settlement gain	(249)	0
Pension plan income	$ (13)	$ (950)
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income	Other income