Employee Benefit Plans - Components of Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 3,261	$ 4,032	$ 8,587	$ 8,327
Defined benefit plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost	5,603	5,935	11,205	11,870
Expected return on plan assets, net of expenses	(6,018)	(6,307)	(12,036)	(12,613)
Amortization of actuarial loss and prior service cost	4	4	9	9
Total for defined benefit pension plan	(411)	(368)	(822)	(734)
SERPs
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	234	234	468	466
Defined contribution plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 3,438	$ 4,166	$ 8,941	$ 8,595