Pension And Other Postretirement Benefit Plans (Fair Values Of Assets Under Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total investments	$ 238,450	$ 244,969
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	58,204	71,561
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	170,436	164,222	[1]
Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	9,810	9,186
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	220,871	221,359
Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	58,204	71,561
Level 1 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	162,667	149,798	[1]
Level 1 [Member] | Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	0	0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	3,101	10,399
Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	0	0
Level 2 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	3,101	10,399	[1]
Level 2 [Member] | Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	0	0
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	14,478	13,211
Level 3 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	0	0
Level 3 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	4,668	4,025	[1]
Level 3 [Member] | Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	$ 9,810	$ 9,186

[1] Includes high yield securities and cash and cash equivalent balances.