Annual report pursuant to Section 13 and 15(d)

Employees Retirement Plans - Pension expense (Details)

v3.22.0.1
Employees Retirement Plans - Pension expense (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2021
USD ($)
item
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Employee Retirement Plans      
Number of regional multi-employer pension plans in which the entity participates | item 47    
Defined contribution plans $ 12,192 $ 10,251 $ 10,015
Multi-employer plans 12,308 11,754 13,241
Total expense related to participation in retirement plans $ 24,500 $ 22,005 $ 23,256