SHARE-BASED COMPENSATION, Assumptions for Option Grants Fair Value Calculation (Details) - $ / shares	12 Months Ended
Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Common Class A [Member]
Expected stock price volatility	24.94%	24.81%	27.69%
Risk-free interest rate	1.72%	2.69%	2.81%
Dividend yield	0.21%	0.22%	0.29%
Forfeiture rate	0.00%	0.00%	0.00%
Expected option life (years)	6 years	6 years	8 years
Weighted average fair value	$ 26.86	$ 19.64	$ 20.93
Heico Common Stock [Member]
Expected stock price volatility		28.52%	31.00%
Risk-free interest rate		2.52%	2.83%
Dividend yield		0.22%	0.24%
Forfeiture rate		0.00%	0.00%
Expected option life (years)		8 years	9 years
Weighted average fair value		$ 33.88	$ 30.00

The estimated forfeiture rate of the underlying shares over the option's term.

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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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- 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.

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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

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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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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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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