Contingent Liabilities and Commitments (Details Textual) (USD $)	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Environmental Matters [Abstract]
Aggregate, Loss Exposure Not Accrued, Low Estimate	$ 5,000,000
Aggregate, Loss Exposure Not Accrued, High Estimate	7,000,000
Accrual for Environmental Loss Contingencies, Total	2,700,000	3,300,000
Accrued Environmental Loss Contingencies, Current	1,100,000	1,100,000
Accrued Environmental Loss Contingencies, Noncurrent	1,600,000	2,200,000
Potentially Responsible Party At Various Superfund And State Waste Disposal Sites [Member]
Environmental Matters [Abstract]
Aggregate, Loss Exposure Not Accrued, High Estimate	500,000
Environmental Restoration Costs [Member]
Environmental Matters [Abstract]
Regulatory Assets	0	0
Minimum [Member]
Environmental Matters [Abstract]
Expected Duration Of Environmental Assessment And Remediation Spending	3 years
Estimated Capital Costs For Compliance With Hazardous Air Pollutant Regulations	3,000,000
Maximum [Member]
Environmental Matters [Abstract]
Expected Duration Of Environmental Assessment And Remediation Spending	5 years
Estimated Capital Costs For Compliance With Hazardous Air Pollutant Regulations	$ 4,000,000