Current report filing

Benefit Plans - Plan Assets (Details)

v3.21.2
Benefit Plans - Plan Assets (Details) - Defined Benefit Pension Plans - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 102,605 $ 87,815
Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 80,395 69,450
Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 22,210 18,365
Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Cash and cash equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 151 289
Cash and cash equivalents | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 151 289
Cash and cash equivalents | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Cash and cash equivalents | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Equity Securities | PQ Corporation Retirement Plan    
Defined Benefit Plan Disclosure [Line Items]    
Target asset plan allocation percentage 45.00%  
Equity Securities | Eco Services Pension Equity Plan    
Defined Benefit Plan Disclosure [Line Items]    
Target asset plan allocation percentage 40.00%  
Equity Securities | Eco Services Hourly Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Target asset plan allocation percentage 60.00%  
U.S. investment funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 28,040 23,344
U.S. investment funds | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 28,040 23,344
U.S. investment funds | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
U.S. investment funds | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
International investment fundsc    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 18,770 15,485
International investment fundsc | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 18,770 15,485
International investment fundsc | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
International investment fundsc | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Fixed income securities | PQ Corporation Retirement Plan    
Defined Benefit Plan Disclosure [Line Items]    
Target asset plan allocation percentage 55.00%  
Fixed income securities | Eco Services Pension Equity Plan    
Defined Benefit Plan Disclosure [Line Items]    
Target asset plan allocation percentage 60.00%  
Fixed income securities | Eco Services Hourly Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Target asset plan allocation percentage 40.00%  
Government securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 16,766 14,379
Government securities | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 16,766 14,379
Government securities | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Government securities | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Corporate bonds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 16,668 14,782
Corporate bonds | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 16,668 14,782
Corporate bonds | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Corporate bonds | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Insurance contracts    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 22,210 18,365
Insurance contracts | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Insurance contracts | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 22,210 18,365
Insurance contracts | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets
Investment fund bonds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets   1,171
Investment fund bonds | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets   1,171
Investment fund bonds | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets  
Investment fund bonds | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets