Employee Benefit Plans - Components of Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 3,790	$ 3,971
Defined contribution plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	4,453	3,978
Defined benefit plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost	4,333	4,103
Expected return on plan assets, net of expenses	(6,224)	(5,820)
Amortization of actuarial loss and prior service cost	1,014	1,487
Total for defined benefit pension plan	(877)	(230)
SERPs
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 214	$ 223