Basis of presentation - Revenue recognition (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Accrued liabilities
Basis of presentation
Loyalty liability	$ 8.4	$ 8.7

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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