Segment information - Reconciliation of other significant reconciling items from segments to consolidated (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting, Other Significant Reconciling Item [Line Items]
Earnings from unconsolidated companies, net of tax	$ 3,474	$ 2,259	$ 3,850	$ 3,094
Capital expenditure to acquire property, plant and equipment	15,420	16,063	27,415	27,076
Unallocated corporate
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditure to acquire property, plant and equipment	971	89	1,401	621
Hotel
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditure to acquire property, plant and equipment	11,499	11,160	20,527	18,292
Hotel | Europe
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditure to acquire property, plant and equipment	6,544	4,126	12,774	7,204
Hotel | North America
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditure to acquire property, plant and equipment	1,850	2,222	2,947	4,391
Hotel | Rest of world
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditure to acquire property, plant and equipment	3,105	4,812	4,806	6,697
Hotel | Part-owned/managed hotels
Segment Reporting, Other Significant Reconciling Item [Line Items]
Earnings from unconsolidated companies, net of tax	683	315	466	228
Trains and Cruises
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditure to acquire property, plant and equipment	2,950	4,814	5,487	8,163
Trains and Cruises | Part-owned/managed trains
Segment Reporting, Other Significant Reconciling Item [Line Items]
Earnings from unconsolidated companies, net of tax	$ 2,791	$ 1,944	$ 3,384	$ 2,866