Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,678	$ 1,603	$ 4,981	$ 4,691
Interest cost	2,212	2,403	6,725	7,316
Expected return on plan assets	(3,373)	(3,676)	(10,145)	(11,032)
Net amortization and deferral	976	1,120	2,928	3,361
Net periodic benefit cost	1,493	1,450	4,489	4,336
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	43	48	137	145
Interest cost	265	286	745	859
Expected return on plan assets	(21)	(24)	(65)	(72)
Net amortization and deferral	(115)	(139)	(346)	(424)
Net periodic benefit cost	$ 172	$ 171	$ 471	$ 508