Pension Plans And Other Postretirement Benefit Plans (Details) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Sep. 30, 2011 Pension Benefits [Member]	Sep. 30, 2010 Pension Benefits [Member]	Sep. 30, 2011 Pension Benefits [Member]	Sep. 30, 2010 Pension Benefits [Member]	Sep. 30, 2011 Other Post-Retirement Benefits [Member]	Sep. 30, 2010 Other Post-Retirement Benefits [Member]	Sep. 30, 2011 Other Post-Retirement Benefits [Member]	Sep. 30, 2010 Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to pension plan	$ 0	$ 21,000,000
Expected contributions to pension plan	26,000,000
Service cost			3,303,000	2,878,000	9,548,000	8,634,000	433,000	219,000	1,299,000	640,000
Interest cost			6,017,000	5,823,000	18,143,000	17,469,000	1,005,000	631,000	3,015,000	1,881,000
Expected return on plan assets			(5,775,000)	(5,347,000)	(17,141,000)	(16,041,000)	(400,000)	(341,000)	(1,200,000)	(1,023,000)
Transition obligation recognition							125,000	126,000	375,000	378,000
Amortization of prior service cost			125,000	163,000	369,000	489,000	(37,000)	(37,000)	(111,000)	(111,000)
Net loss recognition			2,506,000	1,857,000	6,909,000	5,490,000	960,000	297,000	2,634,000	825,000
Net periodic benefit cost			$ 6,176,000	$ 5,374,000	$ 17,828,000	$ 16,041,000	$ 2,086,000	$ 895,000	$ 6,012,000	$ 2,590,000