Liabilities for Dispositions and Discontinued Operations (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Accrual for Environmental Loss Contingencies [Roll Forward]
Liabilities for dispositions and discontinued operations, beginning of period	$ 93,160,000	$ 98,591,000
Expenditures charged to liabilities	(6,915,000)	(8,632,000)
Increase to liabilities	58,000	3,201,000
Liabilities for dispositions and discontinued operations, end of period	86,303,000	93,160,000
Less: Current portion	(11,090,000)	(11,500,000)
Non-current portion	75,213,000	81,660,000
Environmental Loss Contingencies Term Liabilities to Cover Costs	20 years
Environmental Exit Costs, Reasonably Possible Additional Losses, High Estimate	$ 40,000,000