XML 56 R42.htm IDEA: XBRL DOCUMENT v3.21.2
Debt - Text (Detail) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
May 07, 2021
Apr. 30, 2020
Debt Instrument [Line Items]          
Line of Credit Facility, Current Borrowing Capacity $ 410.0        
Line of Credit Facility, Maximum Borrowing Capacity 600.0        
Letter of Credit, Maximum Borrowing Capacity $ 100.0        
Letter of Credit, Maximum Borrowing Capacity, Percentage of Revolving Credit Commitment 50.00%        
Repayments of Long-term Lines of Credit $ 58.0        
Long-term Line of Credit 0.0 $ 0.0      
Letters of Credit Outstanding, Amount 60.3        
Line of Credit Facility, Remaining Borrowing Capacity 349.7        
Debt Repurchase Program, Authorized Amount 30.0       $ 30.0
Proceeds from Long-term Lines of Credit 58.0        
Loss on extinguishment of debt $ 18.1 0.0 $ 0.0    
Secured Debt [Member]          
Debt Instrument [Line Items]          
Debt Instrument, Interest Rate, Stated Percentage 4.00%        
Other note payable $ 12.5        
Senior Notes 3.85% [Member]          
Debt Instrument [Line Items]          
Debt Instrument, Face Amount $ 400.0        
Debt Instrument, Interest Rate, Stated Percentage 3.85%        
Debt Instrument, Redemption Price, Percentage 101.925%        
Debt Instrument, Interest Rate, Effective Percentage 4.10%        
Senior Notes 8.0% [Member]          
Debt Instrument [Line Items]          
Debt Instrument, Redemption, Accrued and Unpaid Interest       $ 1.6  
Debt Instrument, Face Amount $ 350.0        
Debt Instrument, Interest Rate, Stated Percentage 8.00%        
Debt Instrument, Redemption Price       365.6  
Debt Instrument, Redemption, Call Premium       $ 14.0  
Senior Notes 5.0% [Member]          
Debt Instrument [Line Items]          
Debt Instrument, Face Amount $ 300.0        
Debt Instrument, Interest Rate, Stated Percentage 5.00%        
Debt Instrument, Redemption Price, Percentage 102.50%        
Debt Instrument, Interest Rate, Effective Percentage 5.20%        
Senior Notes [Member]          
Debt Instrument [Line Items]          
Debt Issuance Costs, Net $ 8.0 $ 8.9