Pension And Other Postretirement Benefit Plans (Tables)

6 Months Ended

Sep. 30, 2018

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 September 30,						Three Months Ended September 30,
(in thousands of dollars)	2018			2017			2018			2017
Service cost	$	1,452		$	1,318		$	58		$	65
Interest cost	2,485			2,439			330			386
Expected return on plan assets	(3,694		)	(3,717		)	(25		)	(22		)
Net amortization and deferral	902			815			(194		)	(71		)
Net periodic benefit cost	$	1,145		$	855		$	169		$	358

	Pension Benefits						Other Postretirement Benefits
	Six Months Ended September 30,						Six Months Ended September 30,
(in thousands of dollars)	2018			2017			2018			2017
Service cost	$	2,907		$	2,629		$	117		$	129
Interest cost	4,966			4,873			670			769
Expected return on plan assets	(7,388		)	(7,434		)	(50		)	(44		)
Net amortization and deferral	1,804			1,630			(388		)	(142		)
Net periodic benefit cost	$	2,289		$	1,698		$	349		$	712