Taxes - Additional Information (Detail)	3 Months Ended
Mar. 31, 2018 Rate	Mar. 31, 2017 Rate
Operating Loss Carryforwards [Line Items]
Estimated Annual Effective Tax Rate	25.00%	34.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration