Postretirement Benefits - Components of Net Periodic Pension Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Retirement Benefits [Abstract]
Service cost	$ 5,392	$ 8,655
Interest cost	7,834	6,123
Expected return on assets	(9,656)	(8,885)
Prior service cost	269	158
Actuarial (gain) loss	(52)	3,209
Net periodic benefit cost	$ 3,787	$ 9,260