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Commitments and Contingencies - Additional Information (Detail)
204 Months Ended
Jan. 06, 2017
USD ($)
Segment
Dec. 31, 2016
USD ($)
Nov. 30, 2019
USD ($)
Commitments and Contingencies Disclosure [Line Items]      
Remedial investigation and feasibility study   $ 110,000,000  
Performance Guarantee      
Commitments and Contingencies Disclosure [Line Items]      
Letter of credit facility outstanding amount     $ 24,900,000
Portland Harbor Site      
Commitments and Contingencies Disclosure [Line Items]      
Number of sediment decision units | Segment 13    
Estimated undiscounted cost $ 1,700,000,000    
Period for remedial action 13 years    
Period for monitoring 30 years    
New data collection period to reflect actual cost prior to final remedy design 2 years    
Portland Harbor Site | Minimum      
Commitments and Contingencies Disclosure [Line Items]      
Accuracy of cost estimate 30.00%    
Portland Harbor Site | Maximum      
Commitments and Contingencies Disclosure [Line Items]      
Accuracy of cost estimate 50.00%    
Amsted-Maxion Cruzeiro      
Commitments and Contingencies Disclosure [Line Items]      
Note receivable     4,500,000
Greenbrier-Maxion      
Commitments and Contingencies Disclosure [Line Items]      
Note receivable     $ 18,000,000.0