Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Percentage of sales	100.00%	100.00%	100.00%	100.00%
Sales	$ 310,633	$ 368,653	$ 970,743	$ 1,128,350
United States
Disaggregation of Revenue [Line Items]
Sales	250,056	306,050	797,249	946,195
International
Disaggregation of Revenue [Line Items]
Sales	$ 60,577	$ 62,603	$ 173,494	$ 182,155
Nylon
Disaggregation of Revenue [Line Items]
Percentage of sales	25.00%	28.00%	28.00%	28.00%
Caprolactam
Disaggregation of Revenue [Line Items]
Percentage of sales	26.00%	18.00%	22.00%	18.00%
Ammonium Sulfate Fertilizers
Disaggregation of Revenue [Line Items]
Percentage of sales	20.00%	19.00%	23.00%	20.00%
Chemical Intermediates
Disaggregation of Revenue [Line Items]
Percentage of sales	29.00%	35.00%	27.00%	34.00%