CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Net Income		$ 1,815,792	$ 1,625,133	$ 1,283,388
Adjustments:
Depreciation and amortization		1,033,697	951,194	894,915
Impairment losses		33,651	0	0
Net deferred income tax (benefit) expense		(2,679)	1,730	2,608
Loss (gain) on derivative instruments not designated as hedges		61,148	(61,704)	45,670
Share-based compensation expense		46,061	69,459	32,659
Equity investment income		(210,756)	(156,247)	(128,350)
Amortization of debt issuance costs		41,978	45,943	52,795
Gain on sale of property and equipment		0	(30,902)	0
Gain on sale of unconsolidated affiliate		(13,680)	0	0
Recognition of deferred gain		(21,794)	0	0
Changes in operating assets and liabilities:
(Increase) decrease in trade and other receivables, net		(9,573)	(32,043)	4,759
(Increase) decrease in inventories		(23,849)	2,424	(1,679)
(Increase) decrease in prepaid expenses and other assets		(71,770)	20,859	11,519
Increase in accounts payable		91,737	36,780	29,564
Increase in accrued interest		18,773	1,303	7,841
Increase in accrued expenses and other liabilities		42,937	34,215	20,718
Increase in customer deposits		385,990	274,705	188,632
Dividends received from unconsolidated affiliates		243,101	109,677	75,942
Other, net		18,375	(17,960)	(4,291)
Net cash provided by operating activities		3,479,139	2,874,566	2,516,690
Investing Activities
Purchases of property and equipment		(3,660,028)	(564,138)	(2,494,363)
Cash received on settlement of derivative financial instruments		76,529	63,224	110,637
Cash paid on settlement of derivative financial instruments		(98,074)	0	(323,839)
Investments in and loans to unconsolidated affiliates		(27,172)	(10,396)	(9,155)
Cash received on loans to unconsolidated affiliates		124,238	62,303	38,213
Proceeds from the sale of property and equipment		0	230,000	0
Proceeds from the sale of unconsolidated affiliate		13,215	0	0
Acquisition of Silversea Cruises, net of cash acquired		(916,135)	0	0
Other, net	[1]	(1,731)	5,415	(46,385)
Net cash used in investing activities		(4,489,158)	(213,592)	(2,724,892)
Financing Activities
Debt proceeds		8,590,740	5,866,966	7,338,560
Debt issuance costs		(81,959)	(51,590)	(88,241)
Repayments of debt		(6,963,511)	(7,835,087)	(6,365,570)
Proceeds from issuance of commercial paper notes		4,730,286	0	0
Repayments of commercial paper notes		(3,965,450)	0	0
Purchase of treasury stock		(575,039)	(224,998)	(299,960)
Dividends paid		(527,494)	(437,455)	(346,487)
Proceeds from exercise of common stock options		4,264	2,525	2,258
Other, net		(13,764)	3,843	3,249
Net cash provided by (used in) financing activities		1,198,073	(2,675,796)	243,809
Effect of exchange rate changes on cash		(20,314)	2,331	(24,569)
Net increase (decrease) in cash and cash equivalents		167,740	(12,491)	11,038
Cash and cash equivalents at beginning of year		120,112	132,603	121,565
Cash and cash equivalents at end of year		287,852	120,112	132,603
Cash paid during the year for:
Interest, net of amount capitalized		252,466	249,615	256,775
Non-Cash Investing Activities
Contingent consideration for the acquisition of Silversea Cruises		44,000	0	0
Purchases of property and equipment included in accounts payable and accrued expenses and other liabilities		0	139,644	0
Notes receivable issued upon sale of property and equipment		$ 0	$ 20,409	213,042
Divestiture of Pullmantur Holdings				$ 26,000

[1] Amount includes $26.0 million in 2016 related to cash included in the divestiture of Pullmantur Holdings.