Long-term Equity-based Compensation - Black-Scholes Pricing Model For Options (Details) - Stock Options [Member]	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Volatility Rate, Minimum (percentage)	27.31%	26.17%	25.85%
Expected Volatility Rate, Maximum (percentage)	32.15%	30.39%	42.19%
Risk Free Interest Rate, Minimum (percentage)	2.44%	1.59%	0.77%
Risk Free Interest Rate, Maximum (percentage)	3.00%	2.25%	2.01%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Dividend Yield Rate (percentage)	1.16%	1.39%	2.22%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Dividend Yield Rate (percentage)	1.72%	2.43%	3.41%
Employee [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
WEIGHTED-AVERAGE EXPECTED LIFE IN YEARS	4 years	4 years	1 year
Employee [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
WEIGHTED-AVERAGE EXPECTED LIFE IN YEARS	6 years	6 years 6 months	6 years 6 months

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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- Definition

The estimated measure of the maximum 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.

+ References

No definition available.

+ Details

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The estimated measure of the minimum 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.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

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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.

+ References

No definition available.

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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