Annual report pursuant to Section 13 and 15(d)

Income Taxes - Unrecognized tax benefits (Details)

v3.10.0.1
Income Taxes - Unrecognized tax benefits (Details) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2016
Activity within the reserve for unrecognized tax benefits      
Balance at the beginning of the period $ 9.9 $ 7.7 $ 7.8
Additions for tax positions related to the current year 0.3 0.7 0.2
Additions for tax positions of prior years 2.8 3.4 1.7
Reductions for tax positions of prior years (0.6) (1.5) (2.0)
Settlements (0.3) (0.4) 0.0
Balance at the end of the period 12.1 9.9 $ 7.7
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 12.1 9.9  
Additional amounts recognized (released) for interest and penalties 0.9 0.7  
Other amounts accrued for interest and penalties 2.0 $ 1.3  
Amount by which the unrecognized tax benefits could increase or decrease over the next 12 months $ 3.0