Stock Incentive Plan - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of authorized stock for stock incentive plan (in shares)	350,000		350,000
Stock-based compensation expense			$ 571,000	$ 435,000
Shares issued upon exercise of stock options (in shares)	11,427	0	12,423	12,789
Proceeds from stock option exercises	$ 195,000	$ 0	$ 195,000	$ 0
Shares withheld for stock option exercises and related income taxes, amount withheld	$ 154,000	$ 0	$ 227,000	$ 1,000,000
Options granted (in shares)	0	3,775	0	3,775
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, options, contractual term			10 years
Stock incentive plan vesting period, years			3 years
Stock-based compensation expense	$ 31,000	$ 34,000	$ 139,000	$ 100,000
Cashless Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock option exercises	74,000	0	$ 130,000	862,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan vesting period, years			3 years
Stock-based compensation expense	$ 128,000	$ 121,000	$ 432,000	$ 335,000
Restricted units granted (in shares)	0	2,337	0	2,337

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Withheld Shares For Company Expenses

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Gross number of share options (or share units) granted during the period.

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