Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2021

Retirement Benefits, Description [Abstract]

Schedule of Net Benefit Costs

For the three and nine months ended September 30, 2021 and 2020, the components of net periodic benefit cost are as follows:

	Three months ended September 30				Nine months ended September 30
(Dollars in thousands)	2021		2020		2021		2020
Service cost	$	3,838	$	3,570	$	11,514	$	10,709
Interest cost	7,466		8,549		22,398		25,648
Expected return on assets	(19,607)		(16,423)		(58,823)		(49,267)
Amortization of net actuarial loss	6,773		6,332		20,320		18,994
Net periodic (benefit) cost	$	(1,530)	$	2,028	$	(4,591)	$	6,084