Pension Benefit and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2014

Compensation and Retirement Disclosure [Abstract]

Components of net periodic benefit cost

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

(Dollars in thousands)	Pension Benefits												Retirement Health and Life Insurance Benefits
	Three Months Ended						Six Months Ended						Three Months Ended					Six Months Ended
Change in benefit obligation:	June 30, 2014			June 30, 2013			June 30, 2014			June 30, 2013			June 30, 2014		June 30, 2013			June 30, 2014		June 30, 2013
Service cost	$	—		$	956		$	—		$	2,210		$	159	$	170		$	319	$	341
Interest cost	1,990			1,954			4,008			4,015			84		71			167		141
Expected return on plan assets	(3,228		)	(2,731		)	(6,455		)	(5,447		)	—		—			—		—
Amortization of prior service cost	—			31			—			124			—		(57		)	—		(115		)
Amortization of net loss	160			1,049			343			2,525			30		82			61		165
Special termination benefit	—			—			—			—			—		—			—		—
Settlement charge	(33		)	—			77			—			—		—			—		—
Curtailment charge	—			1,537			—			1,537			—		—			—		—
Net periodic benefit cost (income)	$	(1,111	)	$	2,796		$	(2,027	)	$	4,964		$	273	$	266		$	547	$	532