v3.8.0.1
Revenue Recognition - Schedule of Disaggregated of Revenue by Major Source (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Disaggregation of Revenue [Line Items]    
Oil, NGLs and gas sales $ 28,772 $ 26,355
Oil [Member]    
Disaggregation of Revenue [Line Items]    
Oil, NGLs and gas sales 16,343 13,694
NGLs [Member]    
Disaggregation of Revenue [Line Items]    
Oil, NGLs and gas sales 7,332 6,060
Gas [Member]    
Disaggregation of Revenue [Line Items]    
Oil, NGLs and gas sales $ 5,097 $ 6,601