Debt (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Notes payable    
Uncommitted lines of credit $ 44.0 $ 24.8
Other 0.7 0.8
Short-term Debt 44.7 25.6
Long-term debt    
Credit facility 295.0 240.0
Senior notes 225.0 225.0
Industrial development revenue bonds 11.9 11.9
Other 2.8 2.9
Long-term debt $ 534.7 $ 479.8