Fair Value Measurements and Derivative Instruments - Nonrecurring (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment						$ 576,208
Indefinite-life intangible asset, impairment				$ 30,800
Right-of-use assets, impairment			$ 13,300	45,900
Equity method investments, impairment				39,700
Total, impairment		$ 89,899			$ 0	1,354,514	$ 0
Silversea Cruises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment				$ 576,200		576,208
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-life intangible asset, impairment	[1]	0				30,800
Long-lived assets - vessels, impairment	[2]	83,949				560,926
Right-of-use assets, impairment	[3]	0				50,914
Equity method investments, impairment	[4]	0				39,735
Total, impairment		83,949				1,258,583
Nonrecurring | Silversea Cruises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment	[5]	0				576,208
Nonrecurring | Total Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-life intangible asset		318,700				318,700
Long-lived assets - vessels	[2]	577,193				577,193
Right-of-use assets	[3]	67,265				67,265
Equity method investments	[4]	0				0
Total		1,471,736				1,471,736
Nonrecurring | Total Carrying Amount | Silversea Cruises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Silversea Cruises Goodwill	[5]	508,578				508,578
Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-life intangible asset		318,700				318,700
Long-lived assets - vessels	[2]	577,193				577,193
Right-of-use assets	[3]	67,265				67,265
Equity method investments	[4]	0				0
Total		1,471,736				1,471,736
Nonrecurring | Total Fair Value | Silversea Cruises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Silversea Cruises Goodwill	[5]	508,578				508,578
Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-life intangible asset	[1]	318,700				318,700
Long-lived assets - vessels	[2]	577,193				577,193
Right-of-use assets	[3]	67,265				67,265
Equity method investments	[4]	0				0
Total		$ 1,471,736				$ 1,471,736
Nonrecurring | Level 3 | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-lived intangible assets, measurement input		13.25%				13.25%
Nonrecurring | Level 3 | Royalty fee percentage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Indefinite-lived intangible assets, measurement input		3.00%				3.00%
Nonrecurring | Level 3 | Silversea Cruises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Silversea Cruises Goodwill	[5]	$ 508,578				$ 508,578
Nonrecurring | Level 3 | Silversea Cruises | Weighted average cost of capital
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, measurement input		12.75%				12.75%

[1] We estimated the fair value of our indefinite-life intangible asset using a discounted cash flow model and the relief-from-royalty method. For the Silversea Cruises trade name we used a discount rate of 13.25%, comparable to the rate used in valuing the Silversea Cruises reporting unit. Significant inputs in performing the fair value assessment for the trade name were the royalty rate of 3.0% and forecasted net revenues, which takes into consideration expected ship deliveries, including ship options. The fair value of the Silversea Cruises trade name was estimated as of March 31, 2020, the date of the last impairment test.

[2] Impairments primarily related to vessels during the six months ended June 30, 2020 and to certain construction in progress projects during the three months ended September 30, 2020. For the vessels impaired as of March 31, 2020, we estimated the fair value of two of our vessels using a blended indication from the income and cost approaches and the fair value of the remaining vessels was estimated primarily based on their orderly liquidation values. For the vessels impaired as of June 30, 2020, we estimated the fair value of the vessels using a modified market approach based on the carrying values and orderly liquidation values of the vessels. A significant input in performing the fair value assessments for these vessels was management's expected use of the vessels, which takes into consideration forecasted operating results. During the quarter ended September 30, 2020, construction in progress assets were impaired due to a reduction in scope or the decision to not complete the projects. The impairment was calculated based on orderly liquidation values.

[3] Impairments to our right-of-use assets relate to certain of our berthing arrangements and a ship operating lease. We estimated the fair value of the berthing arrangements using estimated projected discounted cash flows and the fair value of the ship operating lease was estimated using a cost approach. The fair value of the berthing arrangements was estimated as of March 31, 2020, the date these assets were last impaired, and a significant input in performing the fair value assessments for these assets was our expected passenger headcount. The fair value of the ship operating lease was estimated as of June 30, 2020, the date this asset was last impaired, and significant inputs in performing the fair value assessment for this asset were current and residual values of the vessel, expected rate of return and remaining lease payments.

[4] We estimated the fair value of our other than temporarily impaired equity-method investments using a discounted cash flow model. A significant input in performing the fair value assessments for these assets was forecasted operating results for these investments. The fair value of these equity-method investments was estimated as of March 31, 2020, the date these assets were last impaired.

[5] We estimated the fair value of the Silversea Cruises reporting unit using a probability-weighted discounted cash flow model in combination with a market based valuation approach. The principal assumptions used in the discounted cash flow model are projected operating results, weighted-average cost of capital and terminal value. Significantly impacting these assumptions were changes in market conditions associated with COVID-19 and its impact to the business and related operating plans. The discounted cash flow model used our 2020 projected operating results as a base. To that base we added future years’ cash flows through 2030 assuming multiple revenue and expense scenarios that reflect the impact of different global economic environments for this period on Silversea Cruises' reporting unit. We assigned a probability to each revenue and expense scenario. We discounted the projected cash flows using rates specific to Silversea Cruises' reporting unit based on its weighted-average cost of capital, which was determined to be 12.75%. A significant input in performing the fair value assessment for the Silversea Cruises goodwill was forecasted operating results, which takes into consideration expected ship deliveries, including ship options. The fair value of Silversea Cruises’ goodwill was estimated as of March 31, 2020, the date of the last impairment test.