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, 2012	Mar. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain), beginning of year	$ 75,138	$ 73,301
Losses (gains) arising during the year	39,461	5,996
Reclassification adjustments during the year	(6,428)	(4,159)
Net actuarial loss (gain), end of year	108,171	75,138
Prior service cost (benefit), beginning of year	(3,393)	(3,145)
Prior Service cost (benefit) arising during the year	0	0
Reclassification adjustments during the year	313	(248)
Prior service cost (benefit), end of year	(3,080)	(3,393)
Total amounts in accumulated other comprehensive loss at end of year, before income taxes	105,091	71,745
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain), beginning of year	(6,722)	(7,452)
Losses (gains) arising during the year	1,475	478
Reclassification adjustments during the year	603	252
Net actuarial loss (gain), end of year	(4,644)	(6,722)
Prior service cost (benefit), beginning of year	0	0
Prior Service cost (benefit) arising during the year	750	0
Reclassification adjustments during the year	(250)	0
Prior service cost (benefit), end of year	500	0
Total amounts in accumulated other comprehensive loss at end of year, before income taxes	$ (4,144)	$ (6,722)