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, 2012	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Contributions to qualified and non-qualified pension plans	$ 1,500
Additional contributions to pension plans expected in the current fiscal year	15,400
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,224	1,290
Interest cost	3,166	3,451
Expected return on plan assets	(3,497)	(3,709)
Net amortization and deferral	2,518	1,342
Net periodic benefit cost	3,411	2,374
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	148	189
Interest cost	576	578
Expected return on plan assets	(31)	(34)
Net amortization and deferral	52	(58)
Net periodic benefit cost	745	675
ERISA-regulated U.S. plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected additional contributions in the current fiscal year	6,500
Non-ERISA regulated and Other Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected additional contributions in the current fiscal year	$ 8,900