Basis of preparation of the financial statements - Significant accounting policies, treasury shares, narrative (Details)	Dec. 31, 2015 USD ($)
Corporate Information And Statement Of IFRS Compliance [Abstract]
Share repurchase plan, amount of approved shares for repurchase (up to)	$ 20,000,000

Stock Repurchase Program, Shares To Be Repurchased, Approved Amount

No definition available.

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Namespace Prefix:	oec_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant