Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments, Fair Value, Hedging Activities, and Concentrations of Credit Risk - Summary of Fair Value Measurements and Financial Statement Presentation (Detail)

v3.19.3
Financial Instruments, Fair Value, Hedging Activities, and Concentrations of Credit Risk - Summary of Fair Value Measurements and Financial Statement Presentation (Detail) - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets $ 216 $ 1
Fair Values of Liabilities   248
Commodity Futures and Options [Member]    
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets 216  
Forward Purchase Contracts [Member]    
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets [1]   1
Fair Values of Liabilities [1]   248
Level 1 [Member]    
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets 216  
Level 1 [Member] | Commodity Futures and Options [Member]    
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets $ 216  
Level 2 [Member]    
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets   1
Fair Values of Liabilities   248
Level 2 [Member] | Forward Purchase Contracts [Member]    
Fair Value Concentration Of Risk Financial Statement Captions [Line Items]    
Fair Values of Assets [1]   1
Fair Values of Liabilities [1]   $ 248
[1] The fair value for Forward Purchase Contracts were previously estimated based on commodity futures market prices.