Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,589	$ 1,455
Interest cost	2,737	2,481
Expected return on plan assets	(4,216)	(3,694)
Net amortization and deferral	698	902
Net periodic benefit cost	808	1,144
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	53	59
Interest cost	333	340
Expected return on plan assets	(27)	(25)
Net amortization and deferral	(152)	(194)
Net periodic benefit cost	$ 207	$ 180