Income Taxes - Deferred Tax Asset (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating loss	$ 396,033	$ 388,317
Property and equipment	8,323	9,862
Other	17,886	10,263
Intangible assets	444	0
Total deferred tax assets	422,686	408,442
Valuation allowance	(394,196)	(383,253)
Net deferred tax assets	28,490	25,189
Deferred tax liabilities:
Investment in Laramie Energy	26,981	18,140
Convertible notes	2,658	3,193
Intangible assets	0	3,978
Other	496	863
Total deferred tax liabilities	30,135	26,174
Total deferred tax liabilities	$ (1,645)	$ (985)