Pension And Other Postretirement Benefit Plans (Tables)

6 Months Ended

Sep. 30, 2015

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [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)	2015			2014			2015			2014
Service cost	$	1,479		$	1,327		$	106		$	114
Interest cost	2,347			2,656			392			481
Expected return on plan assets	(3,577		)	(3,535		)	(15		)	(26		)
Curtailment gain	—			—			—			(1,503		)
Net amortization and deferral	1,199			780			(44		)	(133		)
Net periodic benefit cost	$	1,448		$	1,228		$	439		$	(1,067	)

	Pension Benefits						Other Postretirement Benefits
	Six Months Ended September 30,						Six Months Ended September 30,
(in thousands of dollars)	2015			2014			2015			2014
Service cost	$	2,962		$	2,661		$	214		$	228
Interest cost	4,693			5,325			799			965
Expected return on plan assets	(7,153		)	(7,227		)	(30		)	(52		)
Curtailment gain	—			—			—			(1,503		)
Net amortization and deferral	2,398			1,560			(88		)	(266		)
Net periodic benefit cost	$	2,900		$	2,319		$	895		$	(628	)