Liabilities for Dispositions and Discontinued Operations Analysis of Activity (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance, beginning of period	$ 81,695	$ 90,824
Expenditures charged to liabilities	(4,015)	(9,926)
Increase to liabilities	448	797
Balance, end of period	78,128	81,695
Less: Current portion	(8,686)	(8,105)
Non-current portion	$ 69,442	$ 73,590