Income Taxes - Taxes Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
U.S.—Federal	$ (3,203)	$ (328)	$ 0
U.S.—State	400	0	2
Deferred:
U.S.—Federal	(58,461)	426	(1,321)
U.S.—State	(8,425)	235	0
Total	$ (69,689)	$ 333	$ (1,319)