Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 LinearFeet Case
Commitments and Contingencies (Additional Textual) [Abstract]
Installation of a reactive iron wall covering area	250
Estimated plan cost for initial construction	$ 688,000
Expected operation and maintenance expenses	1,997,000
Estimated Period	30 years
Unresolved cases	32
Liability for estimated costs	$ 50,000
Massachusetts [Member]
Commitments and Contingencies (Textual) [Abstract]
Number of cases pending	234
Number of cases terminated	167
Settlement agreements, cases	35
Washington [Member]
Commitments and Contingencies (Textual) [Abstract]
Number of cases pending	1