Pension And Other Postretirement Benefit Plans (Details) (USD $)	3 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Contributions to qualified and non-qualified pension plans	$ 2,100,000
Additional contributions to pension plans expected in the current fiscal year	7,200,000
Pension Benefits [Member]
Service cost	1,290,000	1,240,000
Interest cost	3,451,000	3,547,000
Expected return on plan assets	(3,709,000)	(3,696,000)
Net amortization and deferral	1,342,000	996,000
Net periodic benefit cost	2,374,000	2,087,000
Other Postretirement Benefits [Member]
Service cost	189,000	204,000
Interest cost	578,000	624,000
Expected return on plan assets	(34,000)	(36,000)
Net amortization and deferral	(58,000)	(78,000)
Net periodic benefit cost	$ 675,000	$ 714,000