Components of Income Tax Expenses (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Current income tax expense (benefit):
Foreign	$ 130	$ (17)	$ 130	$ (35)
U.S. Federal	0	0	0	0
Total current income tax expense (benefit)	130	(17)	130	(35)
Deferred income tax expense (benefit):
U.S. Federal	(3,339)	(300)	(8,303)	5,198
Total deferred income tax expense (benefit)	(3,339)	(300)	(8,303)	5,198
Total income tax expense (benefit)	$ (3,209)	$ (317)	$ (8,173)	$ 5,163

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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Amount of current foreign income tax expense (benefit) pertaining to income (loss) from continuing operations.

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