Commitments and Contingencies (Legal Matters) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended			12 Months Ended
	Jun. 06, 2006 Key Span [Member]	Jun. 24, 2004 Key Span [Member]	Sep. 30, 2012 Allentown, Pennsylvania Natural Gas Explosion [Member] Damage from Natural Gas Explosion [Member] Claims	Oct. 03, 2012 Allentown, Pennsylvania Natural Gas Explosion [Member] Damage from Natural Gas Explosion [Member] Violation	Feb. 09, 2011 Allentown, Pennsylvania Natural Gas Explosion [Member] Damage from Natural Gas Explosion [Member] Persons	Sep. 30, 2012 Pending Litigation [Member] Allentown, Pennsylvania Natural Gas Explosion [Member] Damage from Natural Gas Explosion [Member] Decedent Claims	Sep. 30, 2012 Minimum [Member] Allentown, Pennsylvania Natural Gas Explosion [Member] Damage from Natural Gas Explosion [Member] Claims
Approximate remediation cost spent by claimant		$ 2,300
Environmental exit cost anticipated by claimant		11,000
Percentage of responsible for cleanup cost		50.00%
Environmental exit cost based on third party estimate	10,000
Additional environment exit cost based on claimant estimate	20,000
Deaths from natural gas explosion (in persons)					5
Property claims							100
Claims settled and dismissed			3
Percentage of property claims settled to date (as a percent)			90.00%
Pending claims (in claims)				6		1
Pending claims, number of decedents, in which plaintiffs seeking compensatory and damages (in decendents)						2
Liability insurance deductible			$ 500