Revenue Recognition - Summary of Estimated Revenue Related to Performance Obligations (Detail) $ in Millions	May 31, 2022 USD ($)
Railcar sales
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	$ 2,500.0
Management services
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	124.4
Other
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	7.6
Manufacturing | Railcar sales
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	2,835.7
Manufacturing | Marine
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	40.6
Manufacturing | Conversions
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	227.1
Manufacturing | Railcars intended for syndication
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue type 1	$ 639.8	[1]

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