Retirement Agreements And Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Retirement Benefits [Abstract]
Liability for employee benefits and other payments	$ 13,400		$ 13,400		$ 12,500
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the year	0	$ 0	0	$ 0
Interest cost on the projected benefit obligation	7	8	14	16
Amortization of unrecognized losses	0	0	0	0
Net periodic benefits costs	$ 7	$ 8	$ 14	$ 16