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Share-Based Compensation - Fair Value of Options Granted (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yields	2.39%	1.99%	1.75%
Volatility factors of expected market price of common stock	28.67%	28.60%	28.52%
Risk-free interest rates	2.61%	2.85%	2.42%
Expected life of options	8 years	8 years	8 years

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- References

No definition available.

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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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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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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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Rate of weighted-average expected volatility for award under share-based payment arrangement.

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-Publisher FASB
-Name Accounting Standards Codification
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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.

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