Fair Value Measurements and Derivative Instruments - Derivative Instruments, Interest Rate Risk, Foreign Currency Exchange Rate Risk (Narrative) (Details) $ in Thousands, € in Millions, T in Millions	3 Months Ended		9 Months Ended			12 Months Ended
	Sep. 30, 2020 USD ($) T	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) T	Sep. 30, 2020 EUR (€)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 EUR (€)	Sep. 30, 2020 EUR (€) T
Gains and losses from derivatives involved in hedging relationships
Derivative instrument, credit risk exposure			$ 2,200
Maximum length of time hedged in derivative contract			3 years	3 years
Percentage of debt bearing fixed interest	65.90%		65.90%			62.10%		65.90%
Interest rate swaps
Gains and losses from derivatives involved in hedging relationships
Notional amount	$ 3,500,000		$ 3,500,000			$ 3,500,000
Forward Contracts
Gains and losses from derivatives involved in hedging relationships
Change in fair value of foreign currency forward contracts recognized in earnings	4,900	$ (26,000)	(35,300)		$ (25,200)
Forward Contracts | Not Designated
Gains and losses from derivatives involved in hedging relationships
Notional amount	262,100		262,100
Foreign exchange contracts
Gains and losses from derivatives involved in hedging relationships
Notional amount	$ 3,300,000		$ 3,300,000			$ 2,900,000
Fuel swaps
Gains and losses from derivatives involved in hedging relationships
Discontinued cash flow hedge, nonmonetary amount | T	0.5		0.5					0.5
Fuel swaps | Reclassification out of Accumulated Other Comprehensive Income
Gains and losses from derivatives involved in hedging relationships
Discontinued cash flow hedge, nonmonetary amount | T	0.4		0.4					0.4
Fuel swaps | Other income (expense)
Gains and losses from derivatives involved in hedging relationships
Discontinued cash flow hedge, reclassification loss			$ 76,300
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			14,100,000
Amount deposited for cost of ships on order	$ 770,700		$ 770,700
Percentage of aggregate cost exposed to fluctuations in the euro exchange rate	64.40%		64.40%			65.90%		64.40%
TUI Cruises | Forward Contracts | Designated as Hedging Instrument
Gains and losses from derivatives involved in hedging relationships
Notional amount	$ 287,300		$ 287,300					€ 245.0
Foreign currency debt
Gains and losses from derivatives involved in hedging relationships
Carrying value of non-derivative instrument designated as hedging instrument			333,061			$ 358,078
Foreign currency debt | TUI Cruises
Gains and losses from derivatives involved in hedging relationships
Carrying value of non-derivative instrument designated as hedging instrument			$ 333,100	€ 284.0		$ 358,100	€ 319.0