Income Taxes (Reconciliation from US federal statutory tax rate to UGU effective tax rate) (Details)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
A reconciliation from the U.S. federal statutory tax rate to our effective tax rate
U.S. federal statutory tax rate	35.00%	35.00%	35.00%
Difference in tax rate due to:
State income taxes, net of federal benefit	4.10%	1.60%	4.30%
Other, net	(0.60%)	1.00%	(0.60%)
Effective tax rate	38.50%	37.60%	38.70%