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Maximum shares purchased by employees.

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Maximum stock value of shares purchased by employees.

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Percentage of employee compensation for employee payroll deduction.

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- Definition

Percentage of fair market value of share.

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The total fair value at grant date of restricted shares issued during the period from an approved Stock Option/Stock Issuance Plan.

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- Definition

Share based compensation arrangement by share based payment award options exercise period following termination.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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-Publisher FASB
-Name Accounting Standards Codification
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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Amount of cash outflow to satisfy an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

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- Definition

Date the equity-based award expires, in CCYY-MM-DD format.

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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.

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- Definition

Net number of non-option equity instruments granted to participants.

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- Definition

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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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

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

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No definition available.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Number of share options (or share units) exercised during the current period.

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Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 18, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	0	33,000	18,000
Exercise of common stock options, shares			2,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available for issuance under plan	250,000
Percentage of market value	85.00%
Percentage of employee's payroll deductions limited to employee's compensation	10.00%
Maximum Stock value of shares purchased by employees if one thousand shares purchased	$ 25,000
Maximum number of shares that employee can purchase each period	250
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash payment of income taxes related to grants included in share-based compensation	$ 0.0	$ 0.0	$ 100,000
Restricted Stock [Member] \| Board of Directors non-employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period		12 months
Restricted stock shares granted		75,000
Value of restricted stock granted		$ 51,000
Restricted Stock [Member] \| Key officers and employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period		48 months
Restricted stock shares granted		300,000
Value of restricted stock granted		$ 900,000
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of common stock options, shares	0
Unrecognized compensation costs related to non-vested awards granted	$ 1,800,000
2015 Omnibus Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
1995 Stock option expiry date	Jul. 28, 2015
Maximum number of shares available for issuance under plan				2,125,000
Number of shares available for future grants	1,700,000
2015 Omnibus Equity Incentive Plan [Member] \| Full Value Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award settled against shares	1.2
2015 Omnibus Equity Incentive Plan [Member] \| Partial Value Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award settled against shares	1.0
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	4 years
Stock option expiration period	10 years
2015 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	48 months
Vested stock options exercised period following termination	90 days
2015 Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	12 months
2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future grants	0
2015 Omnibus Equity Incentive Plan and 2005 Stock Option Plan [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock shares granted	88,000