Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Schedule of financial assets and liabilities (Details)

v3.20.1
Fair Value Measurements - Schedule of financial assets and liabilities (Details) - USD ($)
$ in Millions
Mar. 31, 2020
Sep. 30, 2019
Assets:    
Cash and cash equivalents $ 374.0 $ 399.0
Investments in rabbi trust 3.2 4.2
Derivative instruments 2.7 2.5
Liabilities:    
Derivative instruments 6.3 2.6
Level 1    
Assets:    
Cash and cash equivalents 374.0 399.0
Investments in rabbi trust 3.2 4.2
Derivative instruments 0.0 0.0
Liabilities:    
Derivative instruments 0.0 0.0
Level 2    
Assets:    
Cash and cash equivalents 0.0 0.0
Investments in rabbi trust 0.0 0.0
Derivative instruments 2.7 2.5
Liabilities:    
Derivative instruments 6.3 2.6
Level 3    
Assets:    
Cash and cash equivalents 0.0 0.0
Investments in rabbi trust 0.0 0.0
Derivative instruments 0.0 0.0
Liabilities:    
Derivative instruments 0.0 0.0
$900.0 revolving credit facility (excluding outstanding letters of credit)    
Liabilities:    
Debt instruments 537.6  
$900.0 revolving credit facility (excluding outstanding letters of credit) | Level 1    
Liabilities:    
Debt instruments 0.0  
$900.0 revolving credit facility (excluding outstanding letters of credit) | Level 2    
Liabilities:    
Debt instruments 537.6  
$900.0 revolving credit facility (excluding outstanding letters of credit) | Level 3    
Liabilities:    
Debt instruments 0.0  
$500.0 term loan facility    
Liabilities:    
Debt instruments 493.8  
$500.0 term loan facility | Level 1    
Liabilities:    
Debt instruments 0.0  
$500.0 term loan facility | Level 2    
Liabilities:    
Debt instruments 493.8  
$500.0 term loan facility | Level 3    
Liabilities:    
Debt instruments 0.0  
$375.0 senior unsecured notes    
Liabilities:    
Debt instruments 374.4 374.4
Debt instrument, face amount 375.0  
$375.0 senior unsecured notes | Level 1    
Liabilities:    
Debt instruments 371.0 380.6
$375.0 senior unsecured notes | Level 2    
Liabilities:    
Debt instruments 0.0 0.0
$375.0 senior unsecured notes | Level 3    
Liabilities:    
Debt instruments 0.0 0.0
$225.0 term loan facility    
Liabilities:    
Debt instruments 222.2  
$225.0 term loan facility | Level 1    
Liabilities:    
Debt instruments 0.0  
$225.0 term loan facility | Level 2    
Liabilities:    
Debt instruments 222.2  
$225.0 term loan facility | Level 3    
Liabilities:    
Debt instruments 0.0  
$150.0 senior unsecured notes    
Liabilities:    
Debt instruments 150.0 149.9
Debt instrument, face amount 150.0  
$150.0 senior unsecured notes | Level 1    
Liabilities:    
Debt instruments 149.1 152.8
$150.0 senior unsecured notes | Level 2    
Liabilities:    
Debt instruments 0.0 0.0
$150.0 senior unsecured notes | Level 3    
Liabilities:    
Debt instruments 0.0 0.0
$100.0 Series A Notes    
Liabilities:    
Debt instruments 100.0 100.0
$100.0 Series A Notes | Level 1    
Liabilities:    
Debt instruments 0.0 0.0
$100.0 Series A Notes | Level 2    
Liabilities:    
Debt instruments 98.9 108.5
$100.0 Series A Notes | Level 3    
Liabilities:    
Debt instruments 0.0 0.0
Foreign Exchange Forward | Cash flow hedging    
Liabilities:    
Derivative, notional amount $ 238.2 $ 128.9