Leases (Supplemental Balance Sheet Information Related To Leases) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 213,625	$ 220,503
Operating lease liabilities - current portion	22,983	22,699
Operating lease liabilities - non-current portion	205,723	212,806
Total operating lease liabilities	228,706	235,505
Property plant and equipment, gross	380	383
Accumulated depreciation	(281)	(271)
Property plant and equipment, net	99	112
Other current liabilities	49	49
Other long-term liabilities	56	69
Total finance lease liabilities	$ 105	$ 118
Weighted-average remaining lease term - finance leases	2 years	3 years
Weighted-average remaining lease term - operating leases	10 years	11 years
Weighted-average discount rate - finance leases	5.27%	5.27%
Weighted-average discount rate - operating leases	4.71%	4.71%