Components of Income Tax Benefit (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Current income tax expense:
Foreign	$ 179	$ 96
U.S. Federal	566
Total current income tax expense	745	96
Deferred income tax benefit:
U.S. Federal	(1,998)	(3,098)
Actual tax on continuing operations	$ (1,253)	$ (3,002)

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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