Property Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Property, Plant and Equipment [Line Items]
Utilities	$ 2,295,669	$ 2,201,021
Distribution [Member]
Property, Plant and Equipment [Line Items]
Utilities	2,047,780	1,951,889
Transmission [Member]
Property, Plant and Equipment [Line Items]
Utilities	85,430	83,419
General and other, including contruction in process [Member]
Property, Plant and Equipment [Line Items]
Utilities	$ 162,459	$ 165,713