Stock-Based Compensation - Assumptions Used to Calculate Fair Value of Awards (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]
Risk-free rate			1.30%
Volatility			37.00%
Expected term			5 years
Dividend yield			3.60%
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value	$ 5,321	$ 2,630
Compensation cost	$ 1,873	$ 840
Risk-free rate	2.37%	1.62%
Volatility	22.60%	21.40%
Expected term	2 years 10 months 30 days	2 years 10 months 1 day
Dividend yield	0.00%	0.00%
Unrecognized compensation cost	$ 2,739	$ 1,681
Term over which unrecognized compensation cost recognized	2 years	2 years

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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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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- Definition

Unrecognized cost of unvested share-based compensation awards.

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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

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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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- Definition

Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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- Definition

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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-Publisher FASB
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