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Share-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation $ 17,917 $ 17,051 $ 15,425
Share-based compensation capitalized into oil and gas properties $ 5,593 $ 5,797 $ 5,078
Stock option granted (in shares) 0 0 0
Exercise price of stock options outstanding, minimum $ 6.97    
Exercise price of stock options outstanding, maximum $ 47.75    
Restricted stocks issued, shares (in shares) 1,420,475 674,904 848,498
Restricted stocks issued, value $ 23,722 $ 24,593 $ 17,487
Unrecognized compensation cost, weighted-average period of recognition 1 year 8 months    
Unrecognized compensation cost $ 20,423    
Adjustments to additional paid-in capital related to net tax effect of stock options exercises and restricted stock vesting 0 (54) (884)
Net tax impact from stock option exercises and restricted stock vesting $ 1,314 $ 609  
Restricted Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation     15,405
Restricted Stock [Member] | Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period of stock options 1 year    
Restricted Stock [Member] | Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period of stock options 3 years    
Stock Options[Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation     $ 20
2009 plan [Member] | All Employee [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period of stock options 5 years    
Period after which stock option will expire subsequent to award 10 years    
2009 plan [Member] | Non - Employee Directors [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period of stock options 3 years    
Period after which stock option will expire subsequent to award 10 years