Property, Plant and Equipment and Inventory - Allocation of the Cost of the PetroGranada Colombia Limited Acquisition (Details) $ in Thousands	Jan. 25, 2016 USD ($)
Property, Plant and Equipment [Abstract]
Cash	$ 37,727
Oil and gas properties
Oil and gas properties, Proved	12,228
Oil and gas properties, Unproved	15,563
Oil and gas properties, Total	27,791
Net working capital	18,339
Long-term deferred tax liability	(8,402)
Asset acquisition, consideration transferred	37,728
Cash acquired	200
Restricted cash acquired	$ 18,600