Pension and Other Postretirement Employee Benefits (Tables)

6 Months Ended

Jun. 30, 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 June 30,
	Pension						OPEB
(Dollars in thousands)	2017			2016			2017			2016
Service cost	$	1,515		$	1,747		$	4		$	2
Interest cost		3,967			4,258			310			355
Expected return on plan assets		(4,601	)		(4,734	)		—			—
Amortization of prior service cost (credit)		72			129			(2,220	)		(2,218	)
Amortization of actuarial loss		3,386			4,253			371			430
Net periodic cost (benefit)	$	4,339		$	5,653		$	(1,535	)	$	(1,431	)
	Six Months Ended June 30,
	Pension						OPEB
(Dollars in thousands)	2017			2016			2017			2016
Service cost	$	3,377		$	3,254		$	7		$	7
Interest cost		8,048			8,510			631			710
Expected return on plan assets		(9,204	)		(9,500	)		—			—
Amortization of prior service cost (credit)		144			259			(4,439	)		(4,438	)
Amortization of actuarial loss		7,242			8,170			769			858
Net periodic cost (benefit)	$	9,607		$	10,693		$	(3,032	)	$	(2,863	)

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 June 30, 2017
(Dollars in thousands)	Pension			OPEB			Total
Balance at March 31	$	118,231		$	(8,071	)	$	110,160
Amortization of defined benefit items, net of tax:1
Prior service credit (cost)		(44	)		1,354			1,310
Actuarial loss		(2,066	)		(226	)		(2,292	)
Total reclassification for the period		(2,110	)		1,128			(982	)
Balance at June 30	$	116,121		$	(6,943	)	$	109,178
	Three Months Ended June 30, 2016
(Dollars in thousands)	Pension			OPEB			Total
Balance at March 31	$	125,776		$	(12,648	)	$	113,128
Amortization of defined benefit items, net of tax:1
Prior service credit (cost)		(79	)		1,353			1,274
Actuarial loss		(2,594	)		(263	)		(2,857	)
Total reclassification for the period		(2,673	)		1,090			(1,583	)
Balance at June 30	$	123,103		$	(11,558	)	$	111,545

	Six Months Ended June 30, 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)		(88	)		2,708			2,620
Actuarial loss		(4,418	)		(469	)		(4,887	)
Total reclassification for the period		(4,506	)		2,239			(2,267	)
Balance at June 30	$	116,121		$	(6,943	)	$	109,178
	Six Months Ended June 30, 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)		(158	)		2,707			2,549
Actuarial loss		(4,983	)		(524	)		(5,507	)
Total reclassification for the period		(5,141	)		2,183			(2,958	)
Balance at June 30	$	123,103		$	(11,558	)	$	111,545

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