Pension And Other Postretirement Benefit Plans (Tables)

6 Months Ended

Sep. 30, 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 September 30,						Three Months Ended September 30,
(in thousands of dollars)	2017			2016			2017			2016
Service cost	$	1,318		$	1,359		$	65		$	74
Interest cost	2,439			2,467			386			383
Expected return on plan assets	(3,717		)	(3,589		)	(22		)	(11		)
Net amortization and deferral	815			838			(71		)	(100		)
Net periodic benefit cost	$	855		$	1,075		$	358		$	346

	Pension Benefits						Other Postretirement Benefits
	Six Months Ended September 30,						Six Months Ended September 30,
(in thousands of dollars)	2017			2016			2017			2016
Service cost	$	2,629		$	2,720		$	129		$	147
Interest cost	4,873			4,936			769			758
Expected return on plan assets	(7,434		)	(7,178		)	(44		)	(22		)
Net amortization and deferral	1,630			1,676			(142		)	(200		)
Net periodic benefit cost	$	1,698		$	2,154		$	712		$	683