Share-Based Payment Awards - Schedule of Fair Value Assumptions of Market-based Awards (Details) - Time-based and market-based restricted stock units - 2012 Plan - Time-Based Vesting	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility of A&B common stock	22.60%	23.60%
Average volatility of peer companies	23.20%	24.30%
Risk-free interest rate	1.30%	2.60%

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Average Volatility Rate of Peers

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

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)(ii)
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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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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

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