Business Acquisitions Disposition of Assets and Asset Impairments (Details Textuals) (USD $) In Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2010
Business Acquisitions Disposition of Assets and Asset Impairments (Textuals) [Abstract]
Aggregate amount of cash used for business acquisitions	$ 28.0	$ 28.0	$ 0.8
Gain on disposition of assets, net	(17.1)	(17.1)
Gain on disposition of assets and impairments	5.5	10.4
Southern Region [Member]
Business Acquisition [Line Items]
Other Asset Impairment Charges	28.5	28.5
Western Region [Member]
Business Acquisition [Line Items]
Other Asset Impairment Charges	$ 7.2	$ 7.2