Leases (Supplemental Balance Sheet Information Related To Leases) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 226,855	$ 220,503
Operating lease liabilities - current portion	22,976	22,699
Operating lease liabilities - non-current portion	222,918	212,806
Total operating lease liabilities	245,894	235,505
Property plant and equipment, gross	374	383
Accumulated depreciation	(299)	(271)
Property plant and equipment, net	75	112
Other current liabilities	45	49
Other long-term liabilities	36	69
Total finance lease liabilities	$ 81	$ 118
Weighted-average remaining lease term - finance leases	2 years	3 years
Weighted-average remaining lease term - operating leases	11 years	11 years
Weighted-average discount rate - finance leases	5.25%	5.27%
Weighted-average discount rate - operating leases	4.48%	4.71%