XML 65 R54.htm IDEA: XBRL DOCUMENT v3.21.2
Contingencies - Additional Information (Detail) - USD ($)
6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Site Contingency [Line Items]      
Environmental losses accrual $ 22,459,000   $ 22,884,000
Cash expenditures related to legal matters and environmental matters $ 1,267,000 $ 3,075,000  
Contribution for future response costs 5.00%    
Wilmington Site [Member]      
Site Contingency [Line Items]      
Payment of environmental response costs $ 3,105,000    
Minimum [Member]      
Site Contingency [Line Items]      
Environmental losses and legal losses 22,459,000    
Maximum [Member]      
Site Contingency [Line Items]      
Environmental losses and legal losses $ 40,890,000