Tax - Reconciliation of Effective Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation Of Effective Tax Rate [Abstract]
Profit/(loss) before income tax	$ 6,733	$ 9,354	$ 105,430
Adjusted for tax effect of the following items
Income in subsidiary, subject to income tax	131	95	128
Total income tax expense	$ 131	$ 95	$ 128

The amount of profit (loss) for a period before deducting tax expense. [Refer: Profit (loss)]

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
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