Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Contributions to qualified and non-qualified pension plans			$ 6,000,000
Additional contributions to pension plans expected in the current fiscal year	3,000,000		3,000,000
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	891,000	1,261,000	3,455,000	3,743,000
Interest cost	3,413,000	3,601,000	10,250,000	10,704,000
Expected return on plan assets	(3,700,000)	(3,728,000)	(11,055,000)	(11,127,000)
Net amortization and deferral	2,384,000	1,006,000	5,061,000	2,999,000
Net periodic benefit cost	2,988,000	2,140,000	7,711,000	6,319,000
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	188,000	203,000	566,000	611,000
Interest cost	578,000	624,000	1,734,000	1,873,000
Expected return on plan assets	(33,000)	(35,000)	(101,000)	(107,000)
Net amortization and deferral	(58,000)	(77,000)	(175,000)	(233,000)
Net periodic benefit cost	$ 675,000	$ 715,000	$ 2,024,000	$ 2,144,000