Number of aggregate shares issued in relation to share-based compensation arrangement.

No definition available.

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Grant date fair value of share-based awards other than options.

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No definition available.

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Represents lower range of shares vested expressed as a percentage of target number of awards granted.

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No definition available.

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Represents upper range of shares vested expressed as a percentage of target number of awards granted.

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No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Threshold, Percentage

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No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term for Expected Dividend Rate

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No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term for Expected Volatility Rate

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No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term for Risk Free Interest Rate

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No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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- Definition

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

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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- Definition

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).

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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- Definition

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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No definition available.

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- Definition

Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Percentage of vesting of share-based compensation awards.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Number of new stock issued during the period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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Stock Based Compensation - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash compensation expense		$ 1.8	$ 1.0	$ 0.9
2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance (in shares)			326,663
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum shares issuable (in shares)		5,570,000
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)		265,934
Director \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)			207,014
Director \| 2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued (in shares)		58,920
Employee \| 2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued (in shares)		6,258
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding, unvested restricted stock (in shares)		422,928	319,058	280,457	162,171
Performance shares, grants in period (in shares)		332,921	160,453	185,650
Restricted Stock \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeitures (in shares)		0	0	0
Unrecognized compensation expense		$ 1.6	$ 1.2
Weighted average period to recognize the unrecognized compensation expense		1 year 329 days
Fair value of shares vested		$ 1.5	$ 0.6	$ 0.5
Requisite service period		3 years
Restricted Stock \| 2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding, unvested restricted stock (in shares)		6,258
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)		895,201	562,280
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Performance Shares \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash compensation expense		$ 0.1
Unrecognized compensation expense		$ 0.0
Performance Shares \| PSA Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum shares issuable (in shares)		94,043
Performance Shares \| Board of Directors Chairman \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares, grants in period (in shares)	89,629
Performance shares, grants in period	$ 0.4
Performance shares, vested shares as a percentage of target number of awards granted, lower range (as a percent)	0.00%
Performance shares, vested shares as a percentage of target number of awards granted, upper range (as a percent)	200.00%
Award vesting period	3 years
Award vesting threshold (as a percent)	0.33
Fair value assumptions, expected term	3 years
Fair value assumptions, expected term for expected volatility rate	3 years
Fair value assumptions, expected term for risk-free interest rate	3 years
Fair value assumptions, expected term for expected dividend rate	3 years
If TSR Is Less Than 33% \| Performance Shares \| Board of Directors Chairman \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)	0.00%
If TSR Is Greater Than Or Equal To 33% \| Performance Shares \| Board of Directors Chairman \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)	100.00%
If TSR Is Greater Than Or Equal To 33% And TSR Is In Top Quartile Of Identified Peer Group \| Performance Shares \| Board of Directors Chairman \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)	200.00%
If TSR Is Greater Than Or Equal To 33% And TSR Is In Bottom Quartile Of Identified Peer Group \| Performance Shares \| Board of Directors Chairman \| 2010 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)	50.00%