Fair Value Measurements and Derivative Instruments - Derivative Instruments, Interest Rate Risk, Foreign Currency Exchange Rate Risk (Narrative) (Details) $ in Thousands, € in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Mar. 31, 2021 EUR (€)
Gains and losses from derivatives involved in hedging relationships
Derivative instrument, credit risk exposure	$ 4,800
Maximum length of time hedged in derivative contract	3 years	3 years
Percentage of debt bearing fixed interest	68.20%			64.50%		68.20%
Interest rate swaps
Gains and losses from derivatives involved in hedging relationships
Notional amount	$ 3,300,000			$ 3,400,000
Forward Contracts | Not Designated
Gains and losses from derivatives involved in hedging relationships
Notional amount	462,600
Change in fair value of foreign currency forward contracts recognized in earnings	13,500		$ 52,700
Foreign exchange contracts
Gains and losses from derivatives involved in hedging relationships
Notional amount	2,500,000			$ 3,100,000
Cruise ships on order
Gains and losses from derivatives involved in hedging relationships
Aggregate cost of ships on order, not including partner brands on order	12,900,000
Amount deposited for cost of ships on order	$ 602,500
Percentage of aggregate cost exposed to fluctuations in the euro exchange rate	70.50%			66.30%		70.50%
TUI Cruises | Forward Contracts | Designated as Hedging Instrument
Gains and losses from derivatives involved in hedging relationships
Notional amount	$ 288,000					€ 245.0
Foreign currency debt
Gains and losses from derivatives involved in hedging relationships
Carrying value of non-derivative instrument designated as hedging instrument	132,826			$ 263,031
Foreign currency debt | TUI Cruises
Gains and losses from derivatives involved in hedging relationships
Carrying value of non-derivative instrument designated as hedging instrument	$ 132,800	€ 113.0		$ 263,000	€ 215.0