Other balance sheet items - Schedule of Other Liabilities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Jan. 01, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pension obligation	$ 7,138,000		$ 7,138,000		$ 5,990,000
Operating lease liabilities	3,683,000		3,683,000		4,298,000
Unfavorable ground lease liability	1,885,000		1,885,000		1,967,000
Key money	15,619,000		15,619,000		16,731,000
Other	2,146,000		2,146,000		896,000
Total other liabilities	30,471,000		30,471,000		29,882,000
Service cost	200,000		600,000
Non-service cost components of net periodic pension cost (benefit)	200,000	$ 0	700,000	$ 500,000
Advance deposits	$ 68,089,000		68,089,000		$ 62,644,000	$ 29,700,000
Repurchase of ordinary shares not yet settled			$ 1,621,000	$ 0