v3.26.1
Debt, Net - Additional Information (Detail) - USD ($)
1 Months Ended 9 Months Ended
Jan. 31, 2026
May 31, 2026
Feb. 04, 2026
Aug. 31, 2025
European Debt        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity $ 50,300,000      
Line of credit maturity date 2031-01      
Leasing Senior Term Debt        
Debt Instrument [Line Items]        
Periodic principal payment   $ 2,600,000    
Balloon payment   $ 237,000,000    
Swap agreement interest rate   100.00%    
European        
Debt Instrument [Line Items]        
Line of credit, guaranteed amount   $ 59,500,000    
European | Maximum        
Debt Instrument [Line Items]        
Line of credit maturity date   2028-05    
European | Minimum        
Debt Instrument [Line Items]        
Line of credit maturity date   2026-09    
Mexico        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity   $ 56,000,000    
Mexico | Maximum        
Debt Instrument [Line Items]        
Line of credit maturity date   2027-03    
Mexico | Minimum        
Debt Instrument [Line Items]        
Line of credit maturity date   2026-07    
SOFR | Leasing Senior Term Debt        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.625%    
WIBOR | European | Maximum        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.25%    
WIBOR | European | Minimum        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.20%    
EURIBOR | European Debt        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate 3.50%      
EURIBOR | European | Maximum        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.90%    
EURIBOR | European | Minimum        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.00%    
Revolving Credit Facility | North America        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity   $ 600,000,000    
Aggregate amount available to draw down   320,000,000    
Letter of credit facility outstanding amount   $ 29,300,000   $ 5,400,000
Line of credit maturity date   2030-05    
Revolving Credit Facility | European        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity   $ 133,900,000    
Aggregate amount available to draw down   32,500,000    
Revolving Credit Facility | Mexico        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity   156,000,000    
Aggregate amount available to draw down   $ 136,000,000    
Joint venture partner each guaranteed percentage   50.00%    
Revolving Credit Facility | SOFR | North America        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.50%    
Revolving Credit Facility | SOFR Adjustment | North America        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   0.10%    
Revolving Credit Facility | Prime Rate | North America        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   0.50%    
Mexican Railcar Manufacturing Operations Line of Credit 2, 3rd Component of Senior Secured Credit Facilities | Mexico        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   2.00%    
Mexican Railcar Manufacturing Operations Line of Credit 1, 3rd Component of Senior Secured Credit Facilities | Mexico        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   4.25%    
Leasing Warehouse Credit Facility        
Debt Instrument [Line Items]        
Line of credit maturity date   2029-09    
Leasing Warehouse Credit Facility | North America        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity   $ 450,000,000    
Leasing Warehouse Credit Facility | SOFR        
Debt Instrument [Line Items]        
Debt instrument, percentage points added to the reference rate   1.70%    
GBX Leasing Warehouse Facility | 2026 GBXL Notes        
Debt Instrument [Line Items]        
Debt, Principal amount     $ 300,000,000  
Frequency of payments   monthly    
Debt instrument, maturity date   Feb. 22, 2056    
Debt instrument, repayment date   Feb. 21, 2033    
Debt instrument, maturity year   2056    
Debt instruments additional interest rate per annum   4.00%    
GBX Leasing Warehouse Facility | 2026 GBXL Notes | GBXL I Series 2026-1 Class A Secured Railcar Equipment Notes        
Debt Instrument [Line Items]        
Debt, Principal amount   $ 280,400,000    
Debt instrument, interest rate   5.13%    
GBX Leasing Warehouse Facility | 2026 GBXL Notes | GBXL I Series 2026-1 Class B Secured Railcar Equipment Notes        
Debt Instrument [Line Items]        
Debt, Principal amount   $ 19,600,000    
Debt instrument, interest rate   5.30%    
Delayed Draw Facility | Leasing Senior Term Debt        
Debt Instrument [Line Items]        
Line of credit facility maximum capacity   $ 125,000,000    
Delayed Draw Facility | Maximum | Leasing Senior Term Debt        
Debt Instrument [Line Items]        
Debt instrument, maturity month and year   2032-05    
Delayed Draw Facility | Minimum | Leasing Senior Term Debt        
Debt Instrument [Line Items]        
Debt instrument, maturity month and year   2027-08