Defined Pension Plans - Schedule of Net Periodic Pension Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost – benefits earned during the year						$ 4,329
Interest cost on projected benefit obligation						3,908
Expected return on plan assets						(6,049)
Net amortization						1,946
Net periodic pension (benefit) cost	$ (678)	$ 1,103	$ (1,096)	$ 3,159		4,134
Pension Plan | Forecast
Defined Benefit Plan Disclosure [Line Items]
Service cost – benefits earned during the year					$ 963
Interest cost on projected benefit obligation					3,069
Expected return on plan assets					(6,299)
Net amortization					360
Net periodic pension (benefit) cost					(1,907)
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost – benefits earned during the year						121
Interest cost on projected benefit obligation						347
Net amortization						112
Net periodic pension (benefit) cost	$ 160	$ 145	$ 481	$ 435		$ 580
Supplemental Employee Retirement Plan | Forecast
Defined Benefit Plan Disclosure [Line Items]
Service cost – benefits earned during the year					147
Interest cost on projected benefit obligation					291
Net amortization					203
Net periodic pension (benefit) cost					$ 641