Income Taxes (Narrative) (Detail) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 0		$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%	35.00%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount	381,000
Unrecognized Tax Benefits, Period Increase (Decrease)	35,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	256,000		$ 256,000
Income Tax Expense (Benefit)	$ 248,000	$ 143,000

Income Taxes [Line Items]

No definition available.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to repatriation of foreign earnings.

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Amount of interest expense accrued for an underpayment of income taxes.

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Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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