Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Details)

v3.19.3
Fair Value Measurements (Details) - USD ($)
$ in Millions
Sep. 30, 2019
Sep. 25, 2019
Sep. 30, 2018
Sep. 30, 2017
Dec. 15, 2014
Jul. 09, 2010
2010 Notes            
Liabilities:            
Long-term Debt, Gross $ 374.4   $ 149.7      
Additional disclosures            
Stated interest rate   4.50%        
$150 senior unsecured notes            
Liabilities:            
Long-term Debt, Gross 149.9          
Additional disclosures            
Stated interest rate           5.50%
Line of Credit [Member]            
Liabilities:            
Long-term Debt, Gross     95.7      
Series A Notes            
Liabilities:            
Long-term Debt, Gross 100.0   100.0      
Additional disclosures            
Stated interest rate         4.60%  
Level 1            
Assets:            
Cash and cash equivalents 399.0   56.0      
Investments in rabbi trust 4.2   4.3      
Derivative instruments 0.0     $ 0.0    
Liabilities:            
Derivative instruments     0.0 0.0    
Level 1 | 2010 Notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure 380.6   154.9      
Level 1 | $150 senior unsecured notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure 152.8          
Level 1 | Line of Credit [Member]            
Liabilities:            
Debt Instrument, Fair Value Disclosure       0.0    
Level 1 | Series A Notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure     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 2.5   1.9      
Liabilities:            
Derivative instruments 2.6   2.2      
Level 2 | 2010 Notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure     0.0 0.0    
Level 2 | Line of Credit [Member]            
Liabilities:            
Debt Instrument, Fair Value Disclosure     95.7      
Level 2 | Series A Notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure 108.5   102.4      
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    
Level 3 | 2010 Notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure     0.0 0.0    
Level 3 | Line of Credit [Member]            
Liabilities:            
Debt Instrument, Fair Value Disclosure       0.0    
Level 3 | Series A Notes            
Liabilities:            
Debt Instrument, Fair Value Disclosure 0.0     $ 0.0    
Carrying Value            
Assets:            
Cash and cash equivalents 399.0   56.0      
Investments in rabbi trust 4.2   4.3      
Derivative instruments 2.5   1.9      
Liabilities:            
Derivative instruments $ 2.6   $ 2.2