Retirement Agreements And Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Retirement Benefits [Abstract]
Liability for employee benefits and other payments	$ 12,400		$ 12,400		$ 12,200
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	23	25
Amortization of unrecognized losses	0	0	0	0
Net periodic benefits costs	$ 7	$ 8	$ 23	$ 25