Organization and Nature of Business - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Percentage of crude oil and natural gas production concentrated in crude oil	57.00%
Percentage of crude oil and natural gas revenue concentrated in crude oil	81.00%
North Region [Member]
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Percentage of operations concentrated in geographic areas	60.00%
Percentage of revenues concentrated in geographic areas	73.00%
South Region [Member]
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Percentage of operations concentrated in geographic areas	40.00%
Percentage of revenues concentrated in geographic areas	27.00%