Income Taxes - Schedule Presents Net Current and Net Long-Term Deferred Tax Assets and Liabilities by Tax Jurisdiction (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Long-term	$ 1,146
Deferred Tax Assets, Current		$ 0
Deferred Tax Assets, Long-term		248
Deferred Tax Liabilities, Long-term	14,714
Deferred Tax Liabilities, Current		0
Deferred Tax Liabilities, Long-term		15,849
Federal
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Long-term	0
Deferred Tax Assets, Current		0
Deferred Tax Assets, Long-term		0
Deferred Tax Liabilities, Long-term	7,288
Deferred Tax Liabilities, Current		0
Deferred Tax Liabilities, Long-term		7,705
State
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Long-term	0
Deferred Tax Assets, Current		0
Deferred Tax Assets, Long-term		0
Deferred Tax Liabilities, Long-term	424
Deferred Tax Liabilities, Current		0
Deferred Tax Liabilities, Long-term		531
Foreign
Deferred Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Long-term	1,146
Deferred Tax Assets, Current		0
Deferred Tax Assets, Long-term		248
Deferred Tax Liabilities, Long-term	$ 7,002
Deferred Tax Liabilities, Current		0
Deferred Tax Liabilities, Long-term		$ 7,613

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