Derivative Instruments (Derivative (losses) gains in the consolidated statements of operations) (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2017
Mar. 21, 2017
Mar. 31, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Derivative Gains (Losses) [Line Items]            
Change in fair value of commodity price derivatives $ (13,807)          
Settlement gains on commodity price derivatives 1,692          
Total derivative (losses) gains $ (12,115)          
Predecessor            
Derivative Gains (Losses) [Line Items]            
Change in fair value of commodity price derivatives   $ 46,721 $ (35,554) $ (176,607) $ (88,317) $ 228,903
Settlement gains on commodity price derivatives   1,285 47,486 62,626 218,210 2,417
Settlement gains on early terminations of commodity price derivatives       91,144 15,395  
Total derivative (losses) gains   $ 48,006 $ 11,932 $ (22,837) $ 145,288 $ 231,320