Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,479	$ 1,327	$ 2,962	$ 2,661
Interest cost	2,347	2,656	4,693	5,325
Expected return on plan assets	(3,577)	(3,535)	(7,153)	(7,227)
Curtailment gain	0	0	0	0
Net amortization and deferral	1,199	780	2,398	1,560
Net periodic benefit cost	1,448	1,228	2,900	2,319
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	106	114	214	228
Interest cost	392	481	799	965
Expected return on plan assets	(15)	(26)	(30)	(52)
Curtailment gain	0	(1,503)	0	(1,503)
Net amortization and deferral	(44)	(133)	(88)	(266)
Net periodic benefit cost	$ 439	$ (1,067)	$ 895	$ (628)