Retirement Plans and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Cost (Income)

Components of net periodic benefit cost were as follows: 

	Three Months Ended September 30,
	2020		2019		2020		2019
(Dollars in thousands)	Retirement Plans				Other Post Retirement Benefits
Service cost	$	117	$	109	$	27	$	17
Interest cost	425		476		23		23
Expected loss on plan assets	(816)		(772)		—		—
Amortization of net actuarial loss	300		294		7		—
Accretion of prior service cost	—		(45)		—		—
Net periodic benefit cost	$	26	$	62	$	57	$	40

	Nine Months Ended September 30,
	2020		2019		2020		2019
(Dollars in thousands)	Retirement Plans				Other Post Retirement Benefits
Service cost	$	350	$	328	$	82	$	50
Interest cost	1,259		1,428		72		70
Expected loss on plan assets	(2,450)		(2,313)		—		—
Amortization of net actuarial loss	882		882		19		—
Accretion of prior service cost	—		(136)		—		—
Net periodic benefit cost	$	41	$	189	$	173	$	120