| 
           Business and summary of significant accounting policies (Details 4) (USD $) 
        In Millions, unless otherwise specified  | 
        12 Months Ended | 36 Months Ended | 12 Months Ended | 
|---|---|---|---|
| 
           Sep. 30, 2013 
         | 
        
           Sep. 30, 2014 
         | 
        
           Sep. 30, 2012
 
          Maximum 
         | 
      |
| Long Lived Assets Excluding Goodwill [Abstract] | |||
| Impairment of Long-Lived Assets Held-for-use | $ 0 | ||
| Reclassification | |||
| Profit (loss) on immaterial discontinued operations excluded from statement of operations | $ (0.4) | $ 0.1 | 
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- Details 
          
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- Details 
          
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- Definition 
          Other pretax income (loss) amounts relating to a disposal group that is classified as a component of the entity, exclusive of the following elsewhere enumerated categories: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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