Annual report pursuant to Section 13 and 15(d)

Income Taxes - Unrecognized tax benefits (Details)

v3.20.2
Income Taxes - Unrecognized tax benefits (Details) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2018
Activity within the reserve for unrecognized tax benefits      
Balance at the beginning of the period $ 9.7 $ 12.1 $ 9.9
Additions for tax positions related to the current year 0.6 0.3 0.3
Additions for tax positions of prior years 0.7 4.0 2.8
Reductions for tax positions of prior years (4.4) (0.4) (0.6)
Settlements (0.1) (6.3) (0.3)
Balance at the end of the period 35.7 9.7 12.1
Unrecognized Tax Benefits, Increase Resulting from Acquisition 29.2 0.0 $ 0.0
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 35.7 9.7  
Additional amounts recognized (released) for interest and penalties 1.0 0.4  
Other amounts accrued for interest and penalties $ 2.5 0.7  
Amount by which the unrecognized tax benefits could increase or decrease over the next 12 months   $ 2.5