Pension And Other Postretirement Benefit Plans (Tables)

3 Months Ended

Jun. 30, 2021

Retirement Benefits [Abstract]

Components of Company's Net Periodic Benefit Cost

The components of the Company’s net periodic benefit cost were as follows:

	Pension Benefits				Other Postretirement Benefits
	Three Months Ended June 30,				Three Months Ended June 30,
(in thousands of dollars)	2021		2020		2021		2020
Service cost	$	1,650	$	1,541	$	47	$	48
Interest cost	2,259		2,454		239		287
Expected return on plan assets	(3,385)		(3,677)		(22)		(24)
Net amortization and deferral	976		1,121		(115)		(143)
Net periodic benefit cost	$	1,500	$	1,439	$	149	$	168