Share-Based Compensation - Share-Based Compensation Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	140,134
Treasury Stock Reissued Shares For Director Grants	11,650	11,150	9,950
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost	$ 1,109	$ 1,240	$ 950
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	116,716	85,425
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(18,800)	(9,674)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(4,655)	(3,021)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Period Increase (Decrease)	(2,320)	(1,802)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	152,631	116,716	85,425
Allocated Share-based Compensation Expense	$ 7,203
Allocated Share-based Compensation Expense	$ 3,954
Shares Paid for Tax Withholding for Share Based Compensation	5,879	3,293
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings	12,921	6,381
2013 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized for delivery upon the exercise of incentive stock options	600,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease)	92,404
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	61,690	45,788	41,550
Allocated Share-based Compensation Expense		$ 2,701	$ 1,864
2017 Employees Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	48,053
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	750,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	689,773
2017 Non Employee Directors LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	150,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	127,200
Common Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury Stock Reissued Shares For Director Grants	11,650	11,150	9,950
Allocated Share-based Compensation Expense	$ 3,954	$ 2,701	$ 1,864
Expense to be paid next twelve months [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	3,580
Expense to be paid Year Two [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	2,390
Expense to be paid Year Three [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	1,010
Expense to be paid Year Four [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 223
Restricted Stock Units (RSUs) [Member] \| 2017 Employees Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	13,637

Common Shares Authorized for Delivery Upon the Exercise of Incentive Stock Options

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Treasury Stock Reissued Shares For Director Grants

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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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Unrecognized cost of unvested share-based compensation awards.

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- Definition

The number of restricted shares issued as compensation, net of shares for the payment of withholding taxes. This element is to be used only if shares are used in lieu of cash to satisfy all or a portion of withholding taxes.

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No definition available.

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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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The net total number of shares (or other type of equity) under an equity-based award plan, other than a stock option plan, that were granted, vested and forfeited during the reporting period.

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

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

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No definition available.

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Number of options outstanding, including both vested and non-vested options.

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The increase or decrease in number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding, including vested options.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount of capitalized and expensed compensation cost from equity-based compensation arrangements.

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For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

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No definition available.

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