Postretirement Benefits - Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Amounts recognized in other comprehensive income for pension plans:
Net actuarial gain arising during the year	$ (89,768)	$ (75,091)
Amortization of net actuarial loss	(7,320)	(16,106)
Amortization of prior service cost	(1,443)	(1,428)
Plan amendments	1,620	4,059
Total recognized in other comprehensive income	$ (96,911)	$ (88,566)