Leases (Supplemental Balance Sheet Information Related To Leases) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 228,156	$ 220,503
Operating lease liabilities - current portion	23,753	22,699
Operating lease liabilities - non-current portion	220,426	212,806
Total operating lease liabilities	244,179	235,505
Property plant and equipment, gross	378	383
Accumulated depreciation	(291)	(271)
Property plant and equipment, net	87	112
Other current liabilities	49	49
Other long-term liabilities	44	69
Total finance lease liabilities	$ 93	$ 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	5.26%	5.27%
Weighted-average discount rate - operating leases	4.62%	4.71%