Investments in unconsolidated companies - Unconsolidated companies summarized financial data (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summarized financial data for OEH's unconsolidated companies
Current assets	$ 88,721	$ 88,119
Property, plant and equipment, net of accumulated depreciation	208,467	228,970
Other non-current assets	57,575	55,605
Non-current assets	266,042	284,575
Total assets	354,763	372,694
Current liabilities, including $20,543 and $24,793 current portion of third-party debt	89,341	101,668
Long-term debt	129,546	143,187
Other non-current liabilities	5,653	7,892
Non-current liabilities	135,199	151,079
Total shareholders’ equity	130,223	119,947
Total liabilities and shareholders’ equity	354,763	372,694
Revenue	221,599	207,659	$ 191,551
Gross profit	147,825	141,708	135,000
Net earnings	18,614	(20,778)	$ 21,720
Third-party Debt
Summarized financial data for OEH's unconsolidated companies
Current liabilities, including $20,543 and $24,793 current portion of third-party debt	$ 20,543	$ 24,793