Summary of significant accounting policies - Property Lease and Management (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Summary of significant accounting policies
Revenues	$ 10,073	$ 3,569	$ 3,875
Revenue by recognition over time
Summary of significant accounting policies
Revenues	4,431	$ 3,569	$ 3,875
Revenue by recognition at a point in time
Summary of significant accounting policies
Revenues	$ 5,642

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details