Segment Reporting - Additional Information (Detail)
3 Months Ended 12 Months Ended
Dec. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Sep. 30, 2014
USD ($)
Jun. 30, 2014
USD ($)
Mar. 31, 2014
USD ($)
Dec. 31, 2015
USD ($)
Segment
Customer
Dec. 31, 2014
USD ($)
Customer
Dec. 31, 2013
USD ($)
Customer
Segment Reporting Information [Line Items]                      
Number of reporting operating segments | Segment                 4    
Foreign sales $ 663,791,000 $ 558,022,000 $ 661,743,000 $ 1,598,358,000 $ 1,197,994,000 $ 897,408,000 $ 979,661,000 $ 1,994,699,000 $ 3,481,914,000 $ 5,069,762,000 $ 4,683,349,000
Assets 1,000,332,000       $ 1,339,840,000       1,000,332,000 1,339,840,000  
Canada [Member]                      
Segment Reporting Information [Line Items]                      
Foreign sales                 207,700,000 $ 344,300,000 $ 286,600,000
Natural Gas [Member]                      
Segment Reporting Information [Line Items]                      
Assets $ 0               $ 0    
Net Sales and Adjusted Gross Margin [Member] | Maximum [Member]                      
Segment Reporting Information [Line Items]                      
Percentage of net sales                 10.00%    
Sales Revenue, Net [Member] | Maximum [Member]                      
Segment Reporting Information [Line Items]                      
Percentage of net sales                 10.00%   10.00%
Customer Concentration Risk [Member]                      
Segment Reporting Information [Line Items]                      
Number of customers exceeding threshold | Customer                 0 0 0