Revenue Recognition - Summary of Estimated Revenue Related to Performance Obligations (Detail) $ in Millions	Aug. 31, 2022 USD ($)
Railcar sales
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	$ 2,100.0
Services
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	123.8
Other
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	12.3
Manufacturing | Railcar sales
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	2,634.0
Manufacturing | Marine
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	30.9
Manufacturing | Conversions
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	183.6
Manufacturing | Railcars intended for syndication
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	$ 623.7	[1]

[1] Not a performance obligation as defined in Topic 606