Segment and Other Information - Schedule of Gross Sales to Customers Included in Reportable Segments and All Other Customers as a Group (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Gross Sales, Amount	$ 803,522	$ 945,166
Customer Concentration Risk [Member] | Sales Revenue [Member]
Segment Reporting Information [Line Items]
Gross Sales, Percentage	100.00%	100.00%
Customer A [Member]
Segment Reporting Information [Line Items]
Gross Sales, Amount	$ 246,775	$ 345,247
Customer A [Member] | Customer Concentration Risk [Member] | Sales Revenue [Member]
Segment Reporting Information [Line Items]
Gross Sales, Percentage	31.00%	36.00%
Customer B [Member]
Segment Reporting Information [Line Items]
Gross Sales, Amount	$ 207,277	$ 122,057
Customer B [Member] | Customer Concentration Risk [Member] | Sales Revenue [Member]
Segment Reporting Information [Line Items]
Gross Sales, Percentage	26.00%	13.00%
Customer C [Member]
Segment Reporting Information [Line Items]
Gross Sales, Amount	$ 133,876	$ 184,869
Customer C [Member] | Customer Concentration Risk [Member] | Sales Revenue [Member]
Segment Reporting Information [Line Items]
Gross Sales, Percentage	17.00%	20.00%
Customer D [Member]
Segment Reporting Information [Line Items]
Gross Sales, Amount	$ 84,788	$ 74,986
Customer D [Member] | Customer Concentration Risk [Member] | Sales Revenue [Member]
Segment Reporting Information [Line Items]
Gross Sales, Percentage	10.00%	8.00%
Other Customers [Member]
Segment Reporting Information [Line Items]
Gross Sales, Amount	$ 130,806	$ 218,007
Other Customers [Member] | Customer Concentration Risk [Member] | Sales Revenue [Member]
Segment Reporting Information [Line Items]
Gross Sales, Percentage	16.00%	23.00%