Goodwill and Intangible Assets, Net (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]      
Amortization expense $ 0.5 $ 0.5  
Acquired Indefinite-lived Intangible Assets [Line Items]      
Goodwill 20.0   20.5
Water Rights [Member]
     
Acquired Indefinite-lived Intangible Assets [Line Items]      
Indefinite-lived intangible assets 22.9   22.9
Trade Name [Member]
     
Acquired Indefinite-lived Intangible Assets [Line Items]      
Indefinite-lived intangible assets 0.7   0.7
Specialty Fertilizer [Member]
     
Acquired Indefinite-lived Intangible Assets [Line Items]      
Goodwill $ 13.2   $ 13.8
KCI Supply Agreement
     
Finite-Lived Intangible Assets [Line Items]      
Average useful life 50 years    
SOP Production Rights [Member]
     
Finite-Lived Intangible Assets [Line Items]      
Average useful life 25 years    
Lease Rights [Member]
     
Finite-Lived Intangible Assets [Line Items]      
Average useful life 25 years    
Customer Relationships [Member] | Minimum [Member]
     
Finite-Lived Intangible Assets [Line Items]      
Average useful life 7 years    
Customer Relationships [Member] | Maximum [Member]
     
Finite-Lived Intangible Assets [Line Items]      
Average useful life 10 years