Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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+ Details

Transactions with Unconsolidated Joint Ventures (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Joint Venture Partner
Related Party Transaction [Line Items]
Fees earned and payroll costs reimbursed from marketing services arrangement	$ 0.3	$ 0.1	$ 0.5	$ 0.5
Member of Unconsolidated Joint Venture
Related Party Transaction [Line Items]
Royalty and marketing and reservation system fees	4.1	$ 2.2	7.0	$ 6.8
Receivables	$ 2.6		$ 2.6		$ 2.4