Related-Party Transactions - Effect of Related Party Transactions, Amounts Represented in Cost of Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Related Party Transaction [Line Items]
Total cost of goods sold - related party	$ 3,538	$ 3,075	$ 13,831	$ 13,329
Affiliated Entity
Related Party Transaction [Line Items]
Total cost of goods sold - related party	3,538	3,075	13,831	13,329
OCI GP LLC | Affiliated Entity
Related Party Transaction [Line Items]
Total cost of goods sold - related party	3,538	3,075	11,711	13,329
OCI USA Inc. | Affiliated Entity
Related Party Transaction [Line Items]
Total cost of goods sold - related party	$ 0	$ 0	$ 2,120	$ 0