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Summary of Significant Accounting Policies - Schedule of Fair Value Impairments, Average Prices of Oil and Gas Properties And Applicable Discount Rates (Detail)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2016
USD ($)
Sep. 30, 2016
USD ($)
Jun. 30, 2016
USD ($)
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
$ / bbl
$ / Mcf
Sep. 30, 2015
USD ($)
$ / bbl
$ / Mcf
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Impairment of oil and gas properties $ 2,561 $ 113 $ 1,742 $ 22,718 $ 254,246 $ 544,714 $ 1,984 $ 403 $ 27,134 $ 801,347 $ 60,268
Oil Properties                      
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Fair Value         3,030 330,257       3,030  
Impairment of oil and gas properties         $ 16,036 $ 405,308          
Management's Oil Price Outlook | $ / bbl         73.48 73.70          
Management's Gas Price Outlook | $ / Mcf           4.04          
Oil Properties | Minimum                      
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Annual Discount Rate         10.00% 10.00%          
Oil Properties | Maximum                      
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Annual Discount Rate         20.00% 20.00%          
Natural Gas Properties                      
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Fair Value         $ 123,926 $ 61,625       $ 123,926  
Impairment of oil and gas properties         $ 238,210 $ 139,406          
Management's Oil Price Outlook | $ / bbl         70.76 75.91          
Management's Gas Price Outlook | $ / Mcf         3.74 3.91          
Natural Gas Properties | Minimum                      
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Annual Discount Rate         10.00% 10.00%          
Natural Gas Properties | Maximum                      
Fair Value And Impairments Oil And Gas Properties [Line Items]                      
Annual Discount Rate         20.00% 20.00%