Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,282	$ 1,545
Interest cost	2,901	2,335
Expected return on plan assets	(3,888)	(3,324)
Net amortization and deferral	203	1,001
Net periodic benefit cost	498	1,557
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	25	32
Interest cost	264	241
Expected return on plan assets	(16)	(19)
Net amortization and deferral	(189)	(172)
Net periodic benefit cost	$ 84	$ 82