Retirement Plans and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2019

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Cost (Income)

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

	Three Months Ended June 30,
	2019			2018			2019		2018
(Dollars in thousands)	Retirement Plans						Other Post Retirement Benefits
Service cost	$	110		$	140		$	16	$	22
Interest cost	476			439			24		23
Expected return on plan assets	(770		)	(795		)	—		—
Amortization of net actuarial loss	294			281			—		1
Accretion of prior service cost	(46		)	(71		)	—		—
Net periodic benefit cost (income)	$	64		$	(6	)	$	40	$	46

	Six Months Ended June 30,
	2019			2018			2019		2018
(Dollars in thousands)	Retirement Plans						Other Post Retirement Benefits
Service cost	$	219		$	280		$	33	$	44
Interest cost	952			880			47		46
Expected return on plan assets	(1,541		)	(1,591		)	—		—
Amortization of net actuarial loss	588			561			—		2
Accretion of prior service cost	(91		)	(142		)	—		—
Net periodic benefit cost (income)	$	127		$	(12	)	$	80	$	92