Property and Equipment (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Ships	$ 29,872,655	$ 28,348,088
Ship improvements	2,108,922	3,920,800
Ships under construction	1,078,243	1,110,962
Land, buildings and improvements, including leasehold improvements and port facilities	524,849	472,067
Computer hardware and software, transportation equipment and other	1,678,903	1,698,007
Total property and equipment	35,263,572	35,549,924
Less-accumulated depreciation and amortization	(10,016,977)	(10,083,116)
Property and equipment, net	$ 25,246,595	$ 25,466,808