Liabilities for Dispositions and Discontinued Operations Analysis of Activity (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance, January 1	$ 93,160	$ 98,591	$ 104,575
Expenditures charged to liabilities	(9,209)	(8,632)	(8,095)
Increase to liabilities	6,873	3,201	2,111
Balance, December 31	90,824	93,160	98,591
Less: Current Portion	(9,931)	(11,500)	(10,648)
Non-Current Portion	$ 80,893	$ 81,660	$ 87,943