Retirement Plans and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2017

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,
	2017			2016			2017		2016
(Dollars in thousands)	Retirement Plans						Other Post Retirement Benefits
Service cost	$	124		$	170		$	12	$	11
Interest cost	487			519			30		33
Expected return on plan assets	(748		)	(753		)	—		—
Amortization of net actuarial loss	289			322			10		7
Accretion of prior service cost	(71		)	(70		)	—		—
Net periodic benefit cost	$	81		$	188		$	52	$	51

	Six Months Ended June 30,
	2017			2016			2017		2016
(Dollars in thousands)	Retirement Plans						Other Post Retirement Benefits
Service cost	$	275		$	341		$	24	$	23
Interest cost	952			1,037			59		66
Expected return on plan assets	(1,501		)	(1,507		)	—		—
Amortization of net actuarial loss	577			645			21		13
Accretion of prior service cost	(141		)	(141		)	—		—
Net periodic benefit cost	$	162		$	375		$	104	$	102