Pension Plan and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Pension Plan
Pension Plan and Other Postretirement Benefits
Employer cash contributions			$ 12,400	$ 18,900
Estimated cash contributions in the current fiscal year	$ 16,100		16,100
Components of the pension plans and other postretirement benefits
Service cost	9,235	$ 8,308	27,704	26,329
Interest cost	6,329	5,608	18,986	16,245
Expected return on plan assets	(11,307)	(9,873)	(33,920)	(29,605)
Amortization of prior service cost	242	248	727	755
Recognized net actuarial loss	999	2,881	2,997	6,729
Net periodic benefit cost	5,498	7,172	16,494	20,453
Other Benefits
Pension Plan and Other Postretirement Benefits
Employer cash contributions			500	1,900
Estimated cash contributions in the current fiscal year	700		700
Components of the pension plans and other postretirement benefits
Service cost	1,683	1,332	5,048	4,554
Interest cost	1,008	802	3,024	2,413
Expected return on plan assets	(2,482)	(2,194)	(7,445)	(6,577)
Amortization of prior service cost	39	48	117	145
Recognized net actuarial loss	(228)	(145)	(685)	(365)
Net periodic benefit cost	$ 20	$ (157)	$ 59	$ 170