Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Line Items]
Corporate income tax rates		21.00%	35.00%	35.00%
Repatriation of foreign cash		$ 150,000,000
Reduction of tax expense to deferred tax assets liabilities	$ 273,000,000	0	$ 272,900,000	$ 0
Valuation allowance	11,200,000	10,300,000	11,200,000
Deferred tax assets, valuation allowances	23,500,000	24,500,000	23,500,000
Undistributed earnings of foreign subsidiaries		0
Uncertain tax positions or unrecognized tax benefits	0	4,700,000	0	$ 0	$ 0
Uncertain tax positions that would affect the effective tax rate		3,900,000
Uncertain tax positions that would reult in adjustments to deferred taxes		800,000
Unrecognized Tax Benefits, possible decrease		400,000
Interest expense associated with uncertain tax positions		200,000
Unrecognized Tax Benefits, accrued interest expense		300,000
Natronx Technologies LLC
Income Tax [Line Items]
Deferred tax assets, valuation allowances					$ 7,700,000
Quimica Geral Do Nordeste Sa
Income Tax [Line Items]
Deferred tax assets, valuation allowances	2,400,000	1,900,000	2,400,000
Foreign Tax Authority
Income Tax [Line Items]
Loss carryforward		34,000,000
Loss carryforward subject to expiration		$ 600,000
Loss carryforward expiration date		Dec. 31, 2023
Foreign Tax Authority | Unrealized Foreign Tax Credit Carryforwards
Income Tax [Line Items]
Deferred tax assets, valuation allowances	$ 9,900,000	$ 12,300,000	$ 9,900,000