Pension And Other Postretirement Benefit Plans (Recognized In Accumulated Other Comprehensive Income (Loss) On Pretax Basis) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (benefit) arising during the year		$ 22,000
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain), beginning of year	70,488	93,357
Losses (gains) arising during the year	23,353	(12,834)
Reclassification adjustments during the year	12,297	10,035
Net actuarial loss (gain), end of year	81,544	70,488
Prior service cost (benefit), beginning of year	(22,998)	(2,617)
Prior service cost (benefit) arising during the year	(675)	(22,145)
Reclassification adjustments during the year	6,043	1,764
Prior service cost (benefit), end of year	(17,630)	(22,998)
Total amounts in accumulated other comprehensive loss at end of year, before income taxes	63,914	47,490
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain), beginning of year	(9,952)	(3,918)
Losses (gains) arising during the year	2,879	(6,039)
Reclassification adjustments during the year	(671)	(5)
Net actuarial loss (gain), end of year	(6,402)	(9,952)
Prior service cost (benefit), beginning of year	0	226
Prior service cost (benefit) arising during the year	0	0
Reclassification adjustments during the year	0	(226)
Prior service cost (benefit), end of year	0	0
Total amounts in accumulated other comprehensive loss at end of year, before income taxes	$ (6,402)	$ (9,952)