Annual report pursuant to Section 13 and 15(d)

Subsequent Events (Detail)

v3.21.2
Subsequent Events (Detail)
$ in Millions
1 Months Ended 2 Months Ended 3 Months Ended 12 Months Ended
Nov. 29, 2021
USD ($)
shares
Oct. 31, 2021
USD ($)
Nov. 29, 2021
USD ($)
shares
Sep. 30, 2021
USD ($)
shares
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2020
USD ($)
shares
Sep. 30, 2019
USD ($)
shares
Oct. 01, 2021
plant
Subsequent Event [Line Items]                        
Goodwill expected to be deductible to tax purposes | $       $ 68.5           $ 22.6    
Restricted Stock                        
Subsequent Event [Line Items]                        
Aggregate grant date fair value | $       $ 13.6             $ 3.8  
Class A Common Stock                        
Subsequent Event [Line Items]                        
Conversion rate                   1    
Common stock shares issued (in shares)                   36,600,639    
Class A Common Stock | Restricted Stock                        
Subsequent Event [Line Items]                        
Issuance of stock grant awards (in shares)       510,733             292,534  
Class B Common Stock                        
Subsequent Event [Line Items]                        
Initial public offering (in shares)                   2,214,022    
Common stock, shares, outstanding                   15,691,839    
Subsequent Event | Restricted Stock                        
Subsequent Event [Line Items]                        
Aggregate grant date fair value | $ $ 3.2   $ 3.2                  
Subsequent Event | Restricted Stock | Tranche One                        
Subsequent Event [Line Items]                        
Issuance of stock grant awards (in shares) 49,049                      
Award vesting rights, percentage           25.00% 25.00% 25.00% 25.00%      
Subsequent Event | Restricted Stock | Tranche Two                        
Subsequent Event [Line Items]                        
Issuance of stock grant awards (in shares) 30,000                      
Award vesting rights, percentage         50.00% 50.00%            
Subsequent Event | Class A Common Stock                        
Subsequent Event [Line Items]                        
Issuance of stock grant awards (in shares) 79,049                      
Conversion rate     1                  
Common stock, shares, outstanding 40,738,074   40,738,074                  
Subsequent Event | Class B Common Stock                        
Subsequent Event [Line Items]                        
Initial public offering (in shares)     4,059,569                  
Common stock, shares, outstanding 11,632,270   11,632,270                  
South Carolina Acquistions | Subsequent Event                        
Subsequent Event [Line Items]                        
Cash payment to acquire business | $   $ 67.0                    
Goodwill expected to be deductible to tax purposes | $   $ 35.0                    
Number of aggregate facilities | plant                       3