Revenues (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 34,138	$ (33,688)	$ 175,605	$ 2,032,750	$ 2,517,413	$ 3,186,850	$ 2,806,631	$ 2,439,767	$ 2,208,805	$ 10,950,661	$ 9,493,849
Cruise itinerary
Disaggregation of Revenue [Line Items]
Total revenues									2,014,488	10,432,213	9,125,728
Cruise itinerary | North America
Disaggregation of Revenue [Line Items]
Total revenues									1,342,429	6,392,354	5,399,951
Cruise itinerary | Asia/Pacific
Disaggregation of Revenue [Line Items]
Total revenues									411,865	1,529,898	1,463,083
Cruise itinerary | Europe
Disaggregation of Revenue [Line Items]
Total revenues									18,604	1,942,057	1,914,549
Cruise itinerary | Other regions
Disaggregation of Revenue [Line Items]
Total revenues									241,590	567,904	348,145
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues									$ 194,317	$ 518,448	$ 368,121
Passenger ticket | Other regions
Disaggregation of Revenue [Line Items]
Percentage of revenues by country									26.00%	26.00%	29.00%
Passenger ticket | United States
Disaggregation of Revenue [Line Items]
Percentage of revenues by country									67.00%	65.00%	61.00%
Passenger ticket | United Kingdom
Disaggregation of Revenue [Line Items]
Percentage of revenues by country									7.00%	9.00%	10.00%