Pension And Other Postretirement Benefit Plans (Recognized In Accumulated Other Comprehensive Income (Loss) On Pretax Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain), beginning of year	$ 72,605	$ 97,025
Losses (gains) arising during the year	(1,727)	(17,563)
Amortization included in net periodic benefit cost during the year	3,598	6,857
Net actuarial loss (gain), end of year	67,280	72,605
Prior service cost (benefit), beginning of year	(3,406)	(5,402)
Amortization included in net periodic benefit cost during the year	1,919	1,996
Prior service cost (benefit), end of year	(1,487)	(3,406)
Total amounts in accumulated other comprehensive loss at end of year, before income taxes	65,793	69,199
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain), beginning of year	(4,395)	(5,365)
Losses (gains) arising during the year	(2,533)	520
Amortization included in net periodic benefit cost during the year	(247)	(450)
Net actuarial loss (gain), end of year	(6,681)	(4,395)
Prior service cost (benefit), beginning of year	(376)	(564)
Amortization included in net periodic benefit cost during the year	175	188
Prior service cost (benefit), end of year	(201)	(376)
Total amounts in accumulated other comprehensive loss at end of year, before income taxes	$ (6,882)	$ (4,771)