Pension and Postretirement Benefits

9 Months Ended

Sep. 30, 2017

Compensation And Retirement Disclosure [Abstract]

Pension and Postretirement Benefits

7. Pension and Postretirement Benefits

The estimated components of the recorded net periodic benefit cost (credit) for pension and postretirement benefits are as follows:

	Three-Months Ended September 30,
	Pension						Postretirement Benefits
	2017			2016			2017			2016
	(Dollars in Thousands)
Service cost	$	7,457		$	5,542		$	20		$	22
Interest cost		9,729			8,970			182			216
Expected return on assets		(10,691	)		(9,425	)		—			—
Amortization of:
Prior service cost (credit)		34			87			(436	)		(491	)
Actuarial loss (gain)		3,604			3,018			(91	)		(125	)
Net periodic benefit cost (credit)	$	10,133		$	8,192		$	(325	)	$	(378	)

	Nine-Months Ended September 30,
	Pension						Postretirement Benefits
	2017			2016			2017			2016
	(Dollars in Thousands)
Service cost	$	20,060		$	16,624		$	60		$	65
Interest cost		27,074			26,908			547			648
Expected return on assets		(29,818	)		(28,272	)		—			—
Amortization of:
Prior service cost (credit)		237			262			(1,307	)		(1,471	)
Actuarial loss (gain)		10,643			9,055			(273	)		(374	)
Settlement charge		—			59			—			—
Special termination benefit		—			764			—			(8	)
Net periodic benefit cost (credit)	$	28,196		$	25,400		$	(973	)	$	(1,140	)

The components of net periodic benefit cost (credit), other than the service cost component, are included in other nonoperating income, net, in the consolidated statements of earnings and comprehensive earnings.