Property and Equipment (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Ships	$ 27,209,553	$ 23,714,745
Ship improvements	2,965,634	2,410,525
Ships under construction	817,800	642,235
Land, buildings and improvements, including leasehold improvements and port facilities	321,136	250,079
Computer hardware and software, transportation equipment and other	1,120,988	762,512
Total property and equipment	32,435,111	27,780,096
Less-accumulated depreciation and amortization	(8,968,948)	(8,044,916)
Property and equipment, net	$ 23,466,163	$ 19,735,180