Fair Value Measurements and Derivative Instruments (Non-Derivative Instruments) (Details) - Foreign currency debt $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)
Net investment hedge
Carrying Value of Non-derivative instrument Designated as hedging instrument	$ 295,323		$ 311,225
Pullmantur and TUI Cruises
Net investment hedge
Carrying Value of Non-derivative instrument Designated as hedging instrument	295,300	€ 246.0	311,200	€ 295.0
Current portion of long-term debt
Net investment hedge
Carrying Value of Non-derivative instrument Designated as hedging instrument	70,097		61,601
Long-term debt
Net investment hedge
Carrying Value of Non-derivative instrument Designated as hedging instrument	$ 225,226		$ 249,624