Pension And Other Postretirement Benefit Plans (Components Of Company's Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,195	$ 1,224
Interest cost	2,857	3,166
Expected return on plan assets	(3,542)	(3,497)
Net amortization and deferral	2,447	2,518
Net periodic benefit cost	2,957	3,411
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	138	148
Interest cost	532	576
Expected return on plan assets	(30)	(31)
Net amortization and deferral	(17)	52
Net periodic benefit cost	$ 623	$ 745