Commitments and Contingencies (Details 2) (Pennsylvania Department of Environmental Protection (PaDEP), USD $) In Millions, unless otherwise specified	0 Months Ended	24 Months Ended
	Oct. 18, 2012 item	Dec. 31, 2011	Nov. 18, 2011	Dec. 15, 2010 item
Pennsylvania Department of Environmental Protection (PaDEP)
Environmental Matters
Modified Consent Order, number of households to be supplied with potable water				14
Aggregate amount of fines and civil penalties paid to PaDEP		$ 1.3
Aggregate amount of settlement paid to and accepted by the appellants			$ 2.2
Number of appellants who were allowed by PEHB to reinstate their appeal	3