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

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

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

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

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

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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.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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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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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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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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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).

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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.

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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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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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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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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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Number of new stock issued during the period.

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Stock Based Compensation - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Apr. 30, 2018	May 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash compensation expense			$ 1.3	$ 1.8	$ 1.0
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested restricted stock outstanding (in shares)			507,536	422,928	319,058	280,457
Forfeited (in shares)			5,120	0	0
Performance shares, grants in period (in shares)			289,792	332,921	160,453
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
2010 Plan \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested restricted stock outstanding (in shares)			217,163.000
Unrecognized compensation expense			$ 1.9
Weighted average period to recognize the unrecognized compensation expense			1 year 329 days
Fair value of shares vested			$ 1.1	$ 1.5	$ 0.6
Requisite service period			3 years
2010 Plan \| Performance Shares \| Board of Directors Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares, grants in period (in shares)	0	89,629
Performance shares, grants in period		$ 0.4
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
Award vesting period	3 years		3 years
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum shares issuable (in shares)			5,570,000
Common shares reserved for issuance (in shares)			3,865,174
2017 Plan \| Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued (in shares)			131,975
2017 Plan \| Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued (in shares)			292,459
2017 Plan \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested restricted stock outstanding (in shares)			290,373
Unrecognized compensation expense				$ 1.6
2017 Plan \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance (in shares)			1,280,392
Non-cash compensation expense			$ 0.9
Unrecognized compensation expense			2.6
Performance shares, grants in period			$ 3.5
Award vesting period			3 years
2017 Plan \| Performance Shares \| Relative TSR performance Is Less Than The Thirtieth Percentile
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)			0.00%
2017 Plan \| Performance Shares \| Relative TSR Performance Is Equal To The Fiftieth Percentile
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (as a percent)			100.00%
2017 Plan \| Performance Shares \| Board of Directors Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares, grants in period (in shares)			842,792
Fair value assumptions, expected term			3 years
Fair value assumptions, expected term for expected volatility rate			3 years
2010 Plan And 2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance (in shares)				5,598,865
2010 Plan And 2017 Plan \| Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)				265,934
2010 Plan And 2017 Plan \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)				895,201