Ecovyst, Inc. Annual report [Section 13 and 15(d), not S-K Item 405]

Stockholders' Equity - Pre-tax and After-tax Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
After-tax amount
Pre-tax amount	$ 7,576	$ (7,046)	$ (11,870)
Tax benefit/(expense)	3,102	597	4,920
Total other comprehensive income (loss)	10,678	(6,449)	(6,950)
Net gain
After-tax amount
Pre-tax amount	1,295	1,169	1,511
Tax benefit/(expense)	(312)	(291)	(297)
Total other comprehensive income (loss)	983	878	1,214
Net prior service cost
After-tax amount
Pre-tax amount	0	(30)	(125)
Tax benefit/(expense)	0	7	31
Total other comprehensive income (loss)	0	(23)	(94)
Benefit plans, net
After-tax amount
Pre-tax amount	1,295	1,139	1,386
Tax benefit/(expense)	(312)	(284)	(266)
Total other comprehensive income (loss)	983	855	1,120
Net loss from hedging activities
After-tax amount
Pre-tax amount	(12,495)	(3,525)	(17,312)
Tax benefit/(expense)	3,414	881	5,186
Total other comprehensive income (loss)	(9,081)	(2,644)	(12,126)
Foreign currency translation
After-tax amount
Pre-tax amount	18,776	(4,660)	4,056
Tax benefit/(expense)	0	0	0
Total other comprehensive income (loss)	$ 18,776	$ (4,660)	$ 4,056