Health Care, Pension and Other Benefits (Tables)

3 Months Ended

Mar. 31, 2018

Retirement Benefits [Abstract]

Components of net periodic benefit costs for pension and other employee benefit plans

Shown below are the components of the Company’s net periodic benefit cost (credit) for domestic defined benefit pension plans, foreign defined benefit pension plans and postretirement benefits other than pensions:

(Thousands of dollars)	Domestic Defined Benefit Pension Plans						Foreign Defined Benefit Pension Plans						Postretirement Benefits Other than Pensions
	2018			2017			2018			2017			2018			2017
Three Months Ended March 31:
Net periodic benefit cost:
Service cost	$	4,357		$	5,313		$	2,016		$	1,918		$	498		$	543
Interest cost	8,152			6,410			2,352			1,638			2,545			2,643
Expected return on assets	(14,434		)	(10,309		)	(2,685		)	(1,764		)
Recognition of:
Unrecognized prior service cost	379			341			—						(1,642		)	(1,645		)
Unrecognized actuarial loss				1,661			383			(53		)	581			11
Ongoing pension (credit) cost	(1,546		)	3,416			2,066			1,739			1,982			1,552
Curtailment expense	825						—
Net pension costs (credits)	$	(721	)	$	3,416		$	2,066		$	1,739		$	1,982		$	1,552