Stock-Based Compensation - Fair Value Assumptions (Details) - $ / shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 23.50	$ 30.06	$ 27.69
PRSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	15,200	14,396	11,099
Expected Term in Years	2 years 9 months 18 days	2 years 9 months 18 days	2 years 9 months 18 days
Correlation Coefficient Rate	80.50%	79.90%	76.40%
Volatility Rate	23.20%	23.90%	22.30%
PRSU \| Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average Risk Free Interest Rate	1.14%	2.47%	2.39%
Peer Company \| PRSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility Rate, Minimum	18.10%	19.90%	19.00%
Volatility Rate, Maximum	107.60%	75.40%	51.40%
Peer Company \| PRSU \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Correlation Coefficient Rate	16.10%	34.50%	28.20%
Peer Company \| PRSU \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Correlation Coefficient Rate	90.20%	90.70%	94.30%

Share-Based Compensation Arrangement By Share-Based Payment Award, Correlation Coefficient Rate

No definition available.

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- Definition

Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

+ References

No definition available.

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- Definition

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.

+ References

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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.

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- Definition

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.

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- Definition

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

+ References

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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 award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents 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
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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- Definition

Number, before forfeiture, of shares issued under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

+ References

No definition available.

+ Details

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