Pension Benefits and Other Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2015

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Components of net periodic benefit cost

The components of net periodic benefit cost (income) for the periods indicated were:

(Dollars in thousands)	Pension Benefits												Retirement Health and Life Insurance Benefits
	Quarter Ended						Nine Months Ended						Quarter Ended				Nine Months Ended
Change in benefit obligation:	September 30, 2015			September 30, 2014			September 30, 2015			September 30, 2014			September 30, 2015		September 30, 2014		September 30, 2015		September 30, 2014
Service cost	$	—		$	—		$	—		$	—		$	150	$	160	$	450	$	479
Interest cost	1,846			2,004			5,523			6,012			75		83		225		250
Expected return on plan assets	(2,772		)	(3,227		)	(8,314		)	(9,682		)	—		—		—		—
Amortization of net loss	432			172			1,258			515			—		31		—		92
Settlement charge	—			—			—			77			—		—		—		—
Net periodic benefit cost (income)	$	(494	)	$	(1,051	)	$	(1,533	)	$	(3,078	)	$	225	$	274	$	675	$	821