XML 104 R85.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Crude Oil and Natural Gas Property Information - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Oil and Gas Exploration and Production Industries Disclosures [Abstract]      
Development costs included in asset retirement costs $ 6.7 $ 25.8 $ 15.3