Changes in Accumulated Other Comprehensive Income (Loss) (Reclassifications) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net of interest capitalized		$ (299,982)	$ (307,370)	$ (277,725)
Depreciation and amortization expenses		(951,194)	(894,915)	(827,008)
Other income (expense)	[1]	(5,289)	(35,653)	(24,445)
Other indirect operating expenses		(1,010,892)	(1,090,064)	(1,007,926)
Fuel		(681,118)	(713,676)	(795,801)
Reclassification out of accumulated other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		(189,802)	(338,391)	(289,131)
Reclassification out of accumulated other comprehensive income (loss) | Loss on cash flow derivative hedges:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		(188,630)	(337,250)	(291,624)
Reclassification out of accumulated other comprehensive income (loss) | 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		(31,603)	(41,480)	(36,401)
Reclassification out of accumulated other comprehensive income (loss) | Loss on cash flow derivative hedges: | Foreign currency forward contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization expenses		(10,840)	(8,114)	(2,871)
Other income (expense)		(9,472)	(14,342)	7,580
Other indirect operating expenses		0	(207)	0
Reclassification out of accumulated other comprehensive income (loss) | Loss on cash flow derivative hedges: | Collars
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Depreciation and amortization expenses		(2,408)	(2,408)	(1,605)
Reclassification out of accumulated other comprehensive income (loss) | Loss on cash flow derivative hedges: | Fuel contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense)		7,382	13,685	(9,583)
Fuel		(141,689)	(284,384)	(248,744)
Reclassification out of accumulated other comprehensive income (loss) | Actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		(1,172)	(1,141)	(1,414)
Reclassification out of accumulated other comprehensive income (loss) | Prior service costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI		0	0	(293)
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		(1,172)	(1,141)	(1,707)
Reclassification out of accumulated other comprehensive income (loss) | Foreign currency translation adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense)		$ 0	$ 0	$ 4,200

[1] Including a $21.7 million loss related to the 2016 elimination of the Pullmantur reporting lag and a net deferred tax benefit of $12.0 million related to the 2015 Pullmantur impairment.