Pension And Other Postretirement Benefit Plans (Fair Values Of Assets Under Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Total investments	$ 270,349	$ 238,450
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	83,135	58,204
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	177,172	170,436	[1]
Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	10,042	9,810
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	251,336	220,871
Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	83,135	58,204
Level 1 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	168,201	162,667	[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	2,920	3,101
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	2,920	3,101	[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	16,093	14,478
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	6,051	4,668	[1]
Level 3 [Member] | Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total investments	$ 10,042	$ 9,810

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