Debt (Premiums, Discounts and Debt Issuance Costs) (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
Debt Instrument [Line Items]            
Total $ 0   $ 16,970      
Predecessor            
Debt Instrument [Line Items]            
Non-cash expense for write-off of debt issuance costs on Senior Notes     17,756 $ 17,756    
Non-cash expense for write-off of debt discount costs on Senior Notes     4,014 4,014    
Non-cash gain for write-off of debt premium on Senior Notes     (4,800) (4,800)    
Total   $ 0 $ 16,970 $ 16,970 $ 0 $ 0