Pension Plans and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss	$ (1,400)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 3,947	$ 3,100	$ 7,709	$ 7,994
Interest cost		8,217	8,521	16,582	15,753
Expected return on plan assets		(11,356)	(10,922)	(22,584)	(21,844)
Curtailment loss		169		169
Amortization of prior service cost (credit)		126	123	249	246
Net loss recognition		569	1,185	1,359	2,024
Net periodic benefit cost		1,672	2,007	3,484	4,173
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		661	532	1,281	1,350
Interest cost		1,726	1,909	3,472	2,953
Expected return on plan assets		(974)	(891)	(1,948)	(1,782)
Amortization of prior service cost (credit)		(263)	(263)	(526)	(526)
Net loss recognition		88	(8)	179	525
Net periodic benefit cost		$ 1,238	$ 1,279	$ 2,458	$ 2,520