Summary of Principal Components of Net Deferred Income Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	$ 163,437	$ 127,821
Deferred tax assets:
Net operating loss (“NOL”) carryforwards	0	37,345
Total net deferred tax assets	44,610	4,943
Deferred income taxes	1,949	4,943
Deferred Tax Liabilities, Property, Plant and Equipment	33,413	0
Deferred Tax Liabilities, Derivatives	9,248	0
Deferred Tax Liabilities, Net	$ 42,661	$ 0