Components of Net Periodic Benefit Cost (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

	Three Months Ended September 30,								Nine Months Ended September 30,
(Dollar amounts in thousands)	Pension Benefits				Post-Retirement Health Benefits				Pension Benefits				Post-Retirement Health Benefits
	2020		2019		2020		2019		2020		2019		2020		2019
Service cost	$	325	$	304	$	10	$	9	$	975	$	913	$	29	$	26
Interest cost	779		866		32		36		2,337		2,599		94		109
Expected return on plan assets	(1,050)		(896)		—		—		(3,149)		(2,689)		—		—
Net amortization of prior service cost	1		—		—		—		1		1		—		—
Net amortization of net (gain) loss	492		389		—		(4)		1,476		1,168		—		(12)
Net Periodic Benefit Cost	$	547	$	663	$	42	$	41	$	1,640	$	1,992	$	123	$	123