Retirement Plans and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2018

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Cost (Income)

Components of net periodic benefit cost (income) were as follows:

	Three Months Ended September 30,
	2018			2017			2018		2017
(Dollars in thousands)	Retirement Plans						Other Post Retirement Benefits
Service cost	$	140		$	124		$	22	$	12
Interest cost	440			487			23		29
Expected return on plan assets	(849		)	(797		)	—		—
Amortization of net actuarial loss	280			309			1		11
Accretion of prior service cost	(70		)	(71		)	—		—
Net periodic benefit (income) cost	$	(59	)	$	52		$	46	$	52

	Nine Months Ended September 30,
	2018			2017			2018		2017
(Dollars in thousands)	Retirement Plans						Other Post Retirement Benefits
Service cost	$	420		$	399		$	66	$	36
Interest cost	1,320			1,439			69		88
Expected return on plan assets	(2,440		)	(2,298		)	—		—
Amortization of net actuarial loss	841			886			3		32
Accretion of prior service cost	(212		)	(212		)	—		—
Net periodic benefit (income) cost	$	(71	)	$	214		$	138	$	156