Supplemental Oil and Gas Disclosures (Unaudited) Supplemental Oil and Gas Disclosures (Unaudited) - Schedule of Gross and Net Oil and Gas Wells Drilled (Details) - well	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Wells drilled, gross	38
Wells drilled, net	6.3
Wells operated by company		3
Percentage of wells operated by company		8.00%
Oil
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Exploratory wells drilled, gross productive		2
Development wells drilled, gross productive		34
Exploratory wells drilled, net productive		0.7
Development wells drilled, net productive		4.3
Dry
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Exploratory wells drilled, gross nonproductive		1
Development wells drilled, net nonnproductive		1
Exploratory wells drilled, net nonproductive		0.8
Development wells drilled, net unproductive		0.5