Employee Benefit Plans - Components of Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 3,693	$ 3,279	$ 12,280	$ 11,606
Defined benefit plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost	5,628	5,814	16,833	17,684
Expected return on plan assets, net of expenses	(6,018)	(6,302)	(18,054)	(18,915)
Amortization of actuarial loss and prior service cost	5	5	14	14
Total for defined benefit pension plan	(385)	(483)	(1,207)	(1,217)
SERPs
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	233	232	701	698
Defined contribution plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 3,845	$ 3,530	$ 12,786	$ 12,125