Quarterly report pursuant to Section 13 or 15(d)

Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail)

v3.10.0.1
Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Liabilities:    
Commodity derivative liabilities – current $ 80,641 $ 27,777
Derivative Liability, Noncurrent 37,570 13,900
Fair Value, Measurements, Recurring | Commodity contracts    
Liabilities:    
Commodity derivative liabilities – current 80,641 27,777
Derivative Liability, Noncurrent 37,570 13,900
Fair Value, Measurements, Recurring | Commodity contracts | Level 1    
Liabilities:    
Commodity derivative liabilities – current 0 0
Derivative Liability, Noncurrent 0 0
Fair Value, Measurements, Recurring | Commodity contracts | Level 2    
Liabilities:    
Commodity derivative liabilities – current 80,641 27,777
Derivative Liability, Noncurrent 37,570 13,900
Fair Value, Measurements, Recurring | Commodity contracts | Level 3    
Liabilities:    
Commodity derivative liabilities – current 0 0
Derivative Liability, Noncurrent $ 0 $ 0