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Redeemable Noncontrolling Interest - Narrative (Details) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Jan. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Noncontrolling Interest [Line Items]      
Change in redeemable noncontrolling interest   $ 0.0 $ 0.0
Redeemable noncontrolling interest   12.1 12.1
Retained Earnings      
Noncontrolling Interest [Line Items]      
Change in redeemable noncontrolling interest   $ (0.3) $ (0.3)
ATI Flowform [Member]      
Noncontrolling Interest [Line Items]      
Noncontrolling interest held by others (percent)   15.00%  
Subsequent Event [Member] | ATI Flowform [Member]      
Noncontrolling Interest [Line Items]      
Noncontrolling interest held by others (percent) 7.50%    
Noncontrolling interest reacquired (percent) 7.50%    
Redeemable noncontrolling interest reacquired $ 6.1