Ecovyst, Inc. Quarterly report pursuant to Section 13 or 15(d)

Income Taxes (Details)	3 Months Ended		9 Months Ended
Income Taxes (Details)	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate	60.10%	38.40%	54.50%	39.30%