Pension And Other Postretirement Benefit Plans (Tables)

9 Months Ended

Dec. 31, 2017

Defined Benefit Plan [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 December 31,						Three Months Ended December 31,
(in thousands of dollars)	2017			2016			2017			2016
Service cost	$	1,314		$	1,343		$	64		$	73
Interest cost	2,436			2,453			381			378
Expected return on plan assets	(3,717		)	(3,584		)	(22		)	(11		)
Net amortization and deferral	815			843			(71		)	(100		)
Net periodic benefit cost	$	848		$	1,055		$	352		$	340

	Pension Benefits						Other Postretirement Benefits
	Nine Months Ended December 31,						Nine Months Ended December 31,
(in thousands of dollars)	2017			2016			2017			2016
Service cost	$	3,943		$	4,063		$	193		$	220
Interest cost	7,309			7,389			1,150			1,136
Expected return on plan assets	(11,151		)	(10,762		)	(66		)	(33		)
Net amortization and deferral	2,445			2,519			(213		)	(300		)
Net periodic benefit cost	$	2,546		$	3,209		$	1,064		$	1,023