XML 26 R73.htm IDEA: XBRL DOCUMENT v2.4.0.6
Investments - Investments Reported in Other Current and Non-Current Assets (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]    
Funding Commitments $ 7.2  
Assets 54.1 53.8
Chem-Mod LLC [Member]
   
Schedule of Equity Method Investments [Line Items]    
Assets 4.0  
Chem-Mod International LLC [Member]
   
Schedule of Equity Method Investments [Line Items]    
Assets 2.0  
Clean-Coal Investments [Member] | Twelve 2009 Era Clean Coal Production Plants [Member]
   
Schedule of Equity Method Investments [Line Items]    
Funding Commitments 0.4  
Assets 7.8 8.9
Clean-Coal Investments [Member] | Two 2009 Era Clean Coal Plants [Member]
   
Schedule of Equity Method Investments [Line Items]    
Assets 1.3 1.5
Clean-Coal Investments [Member] | Five 2011 Era Clean Coal Production Plants [Member]
   
Schedule of Equity Method Investments [Line Items]    
Assets 13.2  
Clean-Coal Investments [Member] | Ten 2011 Era Clean Coal Production Plants [Member]
   
Schedule of Equity Method Investments [Line Items]    
Funding Commitments 3.9  
Assets 14.3 33.4
Clean-Coal Investments [Member] | Notes Receivable and Interest from Co-Investor [Member]
   
Schedule of Equity Method Investments [Line Items]    
Assets 8.5 8.0
Other Investments [Member]
   
Schedule of Equity Method Investments [Line Items]    
Funding Commitments 2.9  
Assets $ 3.0 $ 2.0