Quarterly report [Sections 13 or 15(d)]

Debt and Financing Arrangements - Narrative (Details)

v3.26.1
Debt and Financing Arrangements - Narrative (Details)
 3 Months Ended 6 Months Ended
Jan. 22, 2026
USD ($)
Mar. 11, 2025
shares
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2025
USD ($)
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2025
USD ($)
Mar. 31, 2026
EUR (€)
shares
Sep. 30, 2025
USD ($)
Sep. 30, 2025
EUR (€)
Line of Credit Facility [Line Items]                  
Debt extinguishment charges     $ 16,343,000 $ 0 $ 16,343,000 $ 0      
Accounts payable, trade     4,557,000   4,557,000     $ 6,136,000  
Other borrowings     $ 579,248,000   $ 579,248,000     710,832,000  
Common Class A                  
Line of Credit Facility [Line Items]                  
Shares issued with shelf registration (in shares) | shares   1,250,000              
Common Class A | ATM Program                  
Line of Credit Facility [Line Items]                  
Shares issued with shelf registration (in shares) | shares   3,000,000              
Shares remaining for sale | shares     1,250,000   1,250,000   1,250,000    
Other borrowings                  
Line of Credit Facility [Line Items]                  
Weighted-average interest rate on outstanding borrowings (as a percent)     1.90% 2.16% 1.90% 2.16% 1.90%    
Other borrowings     $ 6,436,000   $ 6,436,000     7,151,000  
2027 Senior Secured Notes | 2027 Senior Secured Notes                  
Line of Credit Facility [Line Items]                  
Debt issued amount     $ 300,000,000   $ 300,000,000        
Debt issuance costs, gross               3,890,000  
Fixed interest rate (as a percent)     8.625%   8.625%   8.625%    
Redemption price, percentage 104.313%                
Repayments of senior notes $ 320,917,000                
Debt extinguishment charges     $ 16,343,000            
Unamortized financing costs     3,404,000            
Other borrowings     0   $ 0     296,110,000  
Receivables Purchase Agreement                  
Line of Credit Facility [Line Items]                  
Facility limit     75,000,000   75,000,000        
Receivables sold to purchasers     55,800,000   55,800,000     65,600,000  
Unsold receivables     66,342,000   66,342,000     63,720,000  
Principal amount of receivables sold           $ 38,789,000      
Revolving credit facilities | March 2020 Debt Amendment | Line of Credit                  
Line of Credit Facility [Line Items]                  
Maximum amount of borrowings available     700,000,000   700,000,000        
Maximum borrowing amount drawn In foreign currency     350,000,000   $ 350,000,000        
Rate spread adjustment (as a percent)         0.10%        
Interest rate during period (as a percent)         1.50%        
Debt issuance costs, gross     1,576,000   $ 1,576,000        
Unamortized debt costs     4,592,000   4,592,000     3,918,000  
Outstanding borrowings on revolving credit facility     404,750,000   404,750,000     384,233,000  
Other borrowings     404,750,000   $ 404,750,000     385,007,000  
Revolving credit facilities | March 2020 Debt Amendment | Minimum | Line of Credit                  
Line of Credit Facility [Line Items]                  
Interest rate on borrowings (as a percent)         1.00%        
Line of credit facility, unused capacity, commitment fee percentage         0.15%        
Revolving credit facilities | March 2020 Debt Amendment | Maximum | Line of Credit                  
Line of Credit Facility [Line Items]                  
Interest rate on borrowings (as a percent)         2.00%        
Line of credit facility, unused capacity, commitment fee percentage         0.30%        
Secured term loan | March 2020 Debt Amendment | Line of Credit                  
Line of Credit Facility [Line Items]                  
Debt issued amount     150,000,000   $ 150,000,000        
Annual scheduled principal payments     7,500,000   7,500,000        
Maximum available for issuance of trade and standby letters of credit     55,000,000   55,000,000        
Outstanding borrowings     $ 148,807,000   $ 148,807,000        
Weighted-average interest rate on outstanding borrowings (as a percent)     4.18% 4.29% 4.18% 4.29% 4.18%    
Other borrowings     $ 148,807,000   $ 148,807,000     0  
Foreign Line of Credit | Credit Facility With European Bank                  
Line of Credit Facility [Line Items]                  
Maximum amount of borrowings available     6,903,000   6,903,000   € 6,000,000.0    
Outstanding borrowings on revolving credit facility             0 $ 774,000 € 659,000
Weighted-average interest rate on outstanding borrowings (as a percent)       4.60%   4.60%      
Foreign Line of Credit | Bank Guarantees | Credit Facility With European Bank                  
Line of Credit Facility [Line Items]                  
Maximum amount of borrowings available     $ 16,107,000   $ 16,107,000   € 14,000,000.0