Pension and Other Postretirement Employee Benefits (Tables)

3 Months Ended

Mar. 31, 2017

General Discussion Of Pension And Other Postretirement Benefits [Abstract]

Components of Net Periodic Cost (Benefit)

The following tables detail the components of net periodic cost (benefit) of our pension plans and other postretirement employee benefits (OPEB):

	Three Months Ended March 31,
	Pension						OPEB
(Dollars in thousands)	2017			2016			2017			2016
Service cost	$	1,862		$	1,507		$	3		$	5
Interest cost		4,081			4,252			321			355
Expected return on plan assets		(4,603	)		(4,766	)		—			—
Amortization of prior service cost (credit)		72			130			(2,219	)		(2,220	)
Amortization of actuarial loss		3,856			3,917			398			428
Net periodic cost (benefit)	$	5,268		$	5,040		$	(1,497	)	$	(1,432	)

Schedule of Accumulated Other Comprehensive Loss (AOCL)

The following tables detail the pension and OPEB changes in accumulated other comprehensive loss (AOCL) on our Condensed Consolidated Balance Sheets, net of tax:

	Three Months Ended March 31, 2017
(Dollars in thousands)	Pension			OPEB			Total
Balance at January 1	$	120,627		$	(9,182	)	$	111,445
Amortization of defined benefit items, net of tax:1
Prior service credit (cost)		(44	)		1,354			1,310
Actuarial loss		(2,352	)		(243	)		(2,595	)
Total reclassification for the period		(2,396	)		1,111			(1,285	)
Balance at March 31	$	118,231		$	(8,071	)	$	110,160
	Three Months Ended March 31, 2016
(Dollars in thousands)	Pension			OPEB			Total
Balance at January 1	$	128,244		$	(13,741	)	$	114,503
Amortization of defined benefit items, net of tax:1
Prior service credit (cost)		(79	)		1,354			1,275
Actuarial loss		(2,389	)		(261	)		(2,650	)
Total reclassification for the period		(2,468	)		1,093			(1,375	)
Balance at March 31	$	125,776		$	(12,648	)	$	113,128

¹ Amortization of prior service credit (cost) and amortization of actuarial loss are included in the computation of net periodic cost (benefit).