XML 88 R73.htm IDEA: XBRL DOCUMENT v3.8.0.1
Commitments and Contingencies - Additional Information (Detail)
 12 Months Ended
Dec. 11, 2015
USD ($)
Dec. 31, 2017
USD ($)
Property
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Commitments and Contingencies Disclosure [Line Items]        
Expiration year of lease agreements   2029    
Rent and related expense   $ 16,800,000 $ 16,600,000 $ 17,400,000
Number of leased properties | Property   1    
Lease payments   $ 412,000    
Lease agreement expiration year   2020    
Royalty license expiration year   2023    
Capital cost        
Commitments and Contingencies Disclosure [Line Items]        
Remedial alternative, EPA preferred remedy $ 7,300,000