Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,229	$ 891	$ 3,499	$ 3,455
Interest cost	3,174	3,413	9,493	10,250
Expected return on plan assets	(3,544)	(3,700)	(10,238)	(11,055)
Settlements	1,975	0	3,304	0
Net amortization and deferral	2,522	2,384	7,886	5,061
Net periodic benefit cost	5,356	2,988	13,944	7,711
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	151	188	445	566
Interest cost	582	578	1,727	1,734
Expected return on plan assets	(31)	(33)	(93)	(101)
Settlements	0	0	0	0
Net amortization and deferral	56	(58)	156	(175)
Net periodic benefit cost	$ 758	$ 675	$ 2,235	$ 2,024