Exploration, Geologic, and Geophysical Expense (Tables)

9 Months Ended

Sep. 30, 2017

Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]

Cost Incurred in Oil and Gas Property Acquisition, Exploration, and Development Activities Disclosure [Table Text Block]

The following table presents the major components of exploration, geologic, and geophysical expense:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
	(in thousands)
Exploratory dry hole costs	$	41,187	$	—	$	41,187	$	—
Geological and geophysical costs, including seismic purchases	463		—		1,790		—
Operating, personnel and other	258		241		918		688
Total exploration, geologic, and geophysical expense	$	41,908	$	241	$	43,895	$	688