Quarterly report pursuant to Section 13 or 15(d)

Fair Value of Derivative Instruments on Condensed Consolidated Balance Sheets (Detail)

v3.7.0.1
Fair Value of Derivative Instruments on Condensed Consolidated Balance Sheets (Detail) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Derivatives, Fair Value [Line Items]    
Derivative assets, current $ 2,672 $ 0
Derivative Asset, Noncurrent 584 0
Derivative assets 3,256 0
Commodity derivative liabilities – current 0 12,932
Derivative Liability, Noncurrent 90 14,437
Derivative Liability 90 27,369
Commodity contracts    
Derivatives, Fair Value [Line Items]    
Derivative Liability 3,200  
Commodity contracts | Derivative assets/liabilities - current    
Derivatives, Fair Value [Line Items]    
Derivative assets, current 2,672 0
Commodity derivative liabilities – current 0 12,932
Commodity contracts | Noncurrent Derivative Contract [Member]    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Noncurrent 584 0
Derivative Liability, Noncurrent $ 90 $ 14,437