Annual report pursuant to Section 13 and 15(d)

Employee benefit plans and deferred compensation - Narrative (Details)

v3.20.2
Employee benefit plans and deferred compensation - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Percentage of liabilities that can be met plan assets 91.00%    
Investments in mutual funds within the rabbi trust $ 23.2    
United States      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Employer contribution to defined contribution plans 13.2 $ 12.3 $ 7.4
Foreign Plan      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Employer contribution to defined contribution plans $ 18.6 $ 18.6 $ 19.5