Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

Retirement Benefits, Description [Abstract]

Schedule of Net Benefit Costs

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

	Three months ended June 30				Six months ended June 30
(Dollars in thousands)	2021		2020		2021		2020
Service cost	$	4,023	$	3,682	$	7,676	$	7,139
Interest cost	7,528		8,568		14,932		17,099
Expected return on assets	(19,621)		(16,435)		(39,216)		(32,844)
Amortization of net actuarial loss	7,018		6,398		13,547		12,662
Net periodic (benefit) cost	$	(1,052)	$	2,213	$	(3,061)	$	4,056