v3.8.0.1
Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Current:      
Federal $ (66)   $ (265)
Total current provision for income taxes (66)   (265)
Deferred:      
Federal 75,341 $ (24,957) (91,716)
State 1,146 539 (1,424)
Total deferred provision for income taxes $ 76,487 $ (24,418) $ (93,140)