v2.4.0.6
Landfill and Environmental Costs (Details Textual) (USD $)
In Millions, unless otherwise specified
 12 Months Ended 3 Months Ended
Mar. 31, 2013
CubicYards
Landfills
Dec. 31, 2012
Mar. 31, 2012
Dec. 31, 2011
Dec. 31, 2012
Missouri Closed Landfill [Member]
Mar. 31, 2013
Missouri Closed Landfill [Member]
Mar. 31, 2013
Congress Landfill [Member]
Mar. 31, 2013
Countywide Landfill [Member]
Environmental Exit Cost [Line Items]                
Number of active solid waste landfills 191              
Total available disposal capacity (billion in-place cubic yards) 4,800,000,000              
Number of closed landfills 128              
Fair value of assets that are legally restricted for final capping, closure and post-closure obligations $ 54.9 $ 54.8   $ 54.8        
Amount of aggregate potential remediation liability 374              
Environmental remediation expense         74.1      
Remediation liability 557.3 563.7 530.0 543.7   59.0 83.7 51.7
Range of loss for remediation costs (minimum)           45 53 49
Range of loss for remediation costs (maximum)           235 154 70
Expected remediation liability to be paid during the next 12 months             $ 8.2 $ 4.5