Changes in Accumulated Other Comprehensive Income (Loss) (Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net of interest capitalized		$ (333,672)		$ (299,982)		$ (307,370)
Depreciation and amortization expenses	$ (894,915)	(1,033,697)		(951,194)		(894,915)
Other income (Expense)	(35,653)	11,107	[1]	(5,289)	[1]	(35,653)	[1]
Fuel	(713,676)	(710,617)		(681,118)
Reclassification out of accumulated other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		(12,620)		(189,802)		(338,391)
Reclassification out of accumulated other comprehensive income (loss) | Gain (loss) on cash flow derivative hedges:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		(11,133)		(188,630)		(337,250)
Reclassification out of accumulated other comprehensive income (loss) | Gain (loss) on cash flow derivative hedges: | Interest rate swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net of interest capitalized	(41,480)	(10,931)		(31,603)		(41,480)
Reclassification out of accumulated other comprehensive income (loss) | Gain (loss) on cash flow derivative hedges: | Foreign currency forward contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization expenses	(8,114)	(12,843)		(10,840)		(8,114)
Other income (Expense)		12,855		(9,472)		(14,342)
Reclassification out of accumulated other comprehensive income (loss) | Gain (loss) on cash flow derivative hedges: | Foreign currency forward contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other indirect operating expenses	(207)	0		0		(207)
Reclassification out of accumulated other comprehensive income (loss) | Gain (loss) on cash flow derivative hedges: | Foreign currency collar options
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization expenses	(2,408)	0		(2,408)		(2,408)
Reclassification out of accumulated other comprehensive income (loss) | Gain (loss) on cash flow derivative hedges: | Fuel contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (Expense)	$ 13,685	(1,580)		7,382		13,685
Fuel		1,366		(141,689)		(284,384)
Reclassification out of accumulated other comprehensive income (loss) | Actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Payroll and related		(1,487)		(1,172)		(1,141)
Reclassification out of accumulated other comprehensive income (loss) | Amortization of defined benefit plans:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		$ (1,487)		$ (1,172)		$ (1,141)

[1] For the year ended December 31, 2016, Other income (expense) included a $21.7 million loss related to the 2016 elimination of the Pullmantur reporting lag.