Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2021

Retirement Benefits, Description [Abstract]

Schedule of Net Benefit Costs

For the three months ended March 31, 2021 and 2020, the components of net periodic benefit cost are as follows:

	Three months ended March 31
(Dollars in thousands)	2021		2020
Service cost	$	3,653	$	3,457
Interest cost	7,404		8,531
Expected return on assets	(19,595)		(16,409)
Amortization of net actuarial loss	6,529		6,264
Net periodic (benefit) cost	$	(2,009)	$	1,843