The aggregate unrecognized cost of equity-based awards expected to be recognized in the future.

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As of the balance sheet date, the aggregate unrecognized cost of equity-based awards (which are expected to recognize) made to employees under equity-based compensation awards that have yet to vest during remainder of year.

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Percentage of restricted stock units granted as result of meeting growth rates.

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Share-based Compensation Arrangement by Share-based Payment Award incentive stock options outstanding number.

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The number of shares (or other type of equity) which are non-qualified options to purchase under the plan.

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The percentage of number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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Share based compensation arrangement by share based payment award restricted stock options to purchase number of shares.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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 weighted average fair value at grant date for nonvested equity-based awards issued 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 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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No definition available.

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Number of shares authorized for issuance under share-based payment arrangement.

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

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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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Percentage of vesting of award under share-based payment arrangement.

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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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Share-Based Payment Arrangements (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, Granted			0	0
Long Term Incentive Plan 2005 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of incentive stock options outstanding			0
Share-based compensation arrangement by share-based payment award, non-qualified stock options to purchase number of shares			14,157
Long Term Incentive Plan 2015 [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	2,000,000		2,000,000
Share-based compensation arrangement by share-based payment award, restricted stock options to purchase number of shares			383,530
Stock options, Granted			0
Long Term Incentive Plan 2005 and 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested share-based compensation arrangements	$ 0		$ 0
Prior To 2009 Incentive Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| First Anniversary [Member]
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, Percentage	10.00%		10.00%
Prior To 2009 Incentive Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| Second Anniversary [Member]
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, Percentage	20.00%		20.00%
Prior To 2009 Incentive Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| Third Anniversary [Member]
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, Percentage	30.00%		30.00%
Prior To 2009 Incentive Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| Fourth Anniversary [Member]
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, Percentage	40.00%		40.00%
Prior To 2009 Incentive Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation incentive stock options grant under incentive plan termination period			5 years
Prior To 2009 Incentive Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation incentive stock options grant under incentive plan termination period			10 years
Incentive Stock Options 2010 [Member] \| Long Term Incentive Plan 2005 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation incentive stock options grant under incentive plan termination period			10 years
Non Qualified Stock Options [Member] \| Long Term Incentive Plan 2005 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting rights, percentage			100.00%
Stock-based compensation incentive stock options grant under incentive plan termination period			10 years
Share-based payment, award vesting period			6 months
Non Qualified Stock Options [Member] \| Long Term Incentive Plan 2005 [Member] \| 200,000 Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation incentive stock options grant under incentive plan termination period			10 years
Number of options vested or expected to vest	200,000		200,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested share-based compensation arrangements	$ 1,400		$ 1,400
Employee Service Share-based Compensation Nonvested Awards, Total Compensation Cost Expected To Recognize During Remainder Of Year			300
Employee Service Share-based Compensation Nonvested Awards, Total Compensation Cost Expected to Recognize During Remainder of Year Two			500
Employee Service Share-based Compensation Nonvested Awards, Total Compensation Cost Expected to Recognize During Year Three			100
Employee Service Share-based Compensation Nonvested Awards, Total Compensation Cost Expected to Recognized			$ 900
Other than options, forfeited			83,210	182,743
Vested				8,198
Allocated share-based compensation expense	140	$ (43)	$ 197	$ 1
Income tax benefit of share-based payments recognized in income	$ 29	$ 9	$ 41
Restricted Stock Units (RSUs) [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of restricted stock units granted as result of meeting growth rates	50.00%		50.00%
Restricted Stock Units (RSUs) [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of restricted stock units granted as result of meeting growth rates	150.00%		150.00%
Restricted Stock Units (RSUs) [Member] \| Long Term Incentive Plan 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options, grant date fair value					$ 10.87	$ 10.20	$ 11.41	$ 11.10