Investments in unconsolidated companies - Summarized financial data for investments in unconsolidated companies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Summarized financial data for OEH's unconsolidated companies
Current assets	$ 83,258		$ 96,247
Property, plant and equipment, net of accumulated depreciation	298,338		295,662
Other non-current assets	29,651		29,442
Non-current assets	327,989		325,104
Total assets	411,247		421,351
Current liabilities, including $21,120 and $21,021 current portion of third-party debt	91,252		89,785
Long-term debt	148,709		153,876
Other non-current liabilities	28,005		27,545
Non-current liabilities	176,714		181,421
Total shareholders’ equity	143,281		150,145
Total liabilities and shareholders’ equity	411,247		$ 421,351
Equity Method Investment, Summarized Financial Information, Income Statement
Revenue	39,465	$ 38,738
Gross profit	25,519	25,844
Net earnings	$ 827	$ 1,804