ACQUISITIONS (Details Textuals) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Business Acquisition [Line Items]
Net sales	$ 426,178	$ 386,410	$ 468,146	$ 506,275	$ 541,529	$ 532,324	$ 515,648	$ 466,146	$ 1,787,009	$ 2,055,647	$ 1,777,721
Net income	62,327	$ 54,316	$ 75,453	$ 121,888	85,684	$ 81,098	$ 81,782	$ 79,332	313,984	327,896	259,233
Acquisition Costs					3,200					3,200
Payments to Acquire Businesses, Net of Cash Acquired									163,939	240,841	$ 59,775
Contingent consideration, liability	$ 41,974				18,326				$ 41,974	$ 18,326
Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									10 years	11 years	7 years
Intellectual Property [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									11 years	15 years	10 years
STE [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	15.00%								15.00%
Solid Sealing Technology [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	15.00%								15.00%
Research Electronics International [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	25.00%								25.00%
Decavo [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	19.90%								19.90%
Apex [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	7.30%								7.30%
FY2019 Acquisition [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired										$ 241,084
Cash Acquired from Acquisition										2,466
Pro Forma Revenue											$ 1,879,700
Decavo [Member]
Business Acquisition [Line Items]
Amount of contingent purchase consideration, the company could be required to pay	$ 2,100								$ 2,100
Connect Tech [Member] | Existing Management [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	10.01%								10.01%
TSID [Member] | Existing Management [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	25.00%								25.00%
Quell [Member] | Existing Management [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	19.90%								19.90%
HEICO Electronic [Member] | TTT-Cubed [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									TTT-Cubed, Inc.
Description of Acquired Entity									TTT is a designer and manufacturer of Radio Frequency (RF) Sources, Detectors, and Controllers for a certain wide range of aerospace and defense applications.
HEICO Electronic [Member] | Bernier Connect SAS [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Bernier Connect SAS
Description of Acquired Entity									Bernier is a designer and manufacturer of interconnect products used in demanding defense, aerospace and industrial applications, primarily for communications-related purposes.
HEICO Electronic [Member] | Bernier Connect SAS [Member] | Moulages Plastiques Industriels [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Moulages Plastiques Industriels de L'essonne
Description of Acquired Entity									a plastics manufacturer.
Business Acquisition, Percentage of Voting Interests Acquired	70.00%								70.00%
HEICO Electronic [Member] | Research Electronics International [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Research Electronics International, LLC
Description of Acquired Entity									REI is a designer and manufacturer of TSCM equipment to detect devices used for espionage and information theft.
Business Acquisition, Percentage of Voting Interests Acquired	75.00%								75.00%
HEICO Electronic [Member] | Solid Sealing Technology [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Solid Sealing Technology, Inc.
Description of Acquired Entity									SST designs and manufactures high-reliability ceramic-to-metal feedthroughs and connectors for demanding environments within the defense, industrial, life science, medical, research, semiconductor, and other markets.
Business Acquisition, Percentage of Voting Interests Acquired	85.00%								85.00%
HEICO Electronic [Member] | Freebird [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Freebird Semiconductor Corporation
Description of Acquired Entity									Freebird is a fabless design and manufacturing company that offers advanced high-reliability wide-band gap power switching technology.
Business Acquisition, Percentage of Voting Interests Acquired	50.00%								50.00%
HEICO Electronic [Member] | Apex [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Apex Microtechnology, Inc.
Description of Acquired Entity									Apex designs and manufactures precision power analog monolithic, hybrid and open frame components for a certain wide range of aerospace, defense, industrial, measurement, medical and test applications.
Business Acquisition, Percentage of Voting Interests Acquired	92.70%								92.70%
HEICO Electronic [Member] | Specialty Silicone Products [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Specialty Silicone Products, Inc.
Description of Acquired Entity									SSP designs and manufactures silicone material for a variety of demanding applications used in aerospace, defense, research, oil and gas, testing, pharmaceuticals and other markets.
HEICO Electronic [Member] | FY 2017 Acquisition [Member]
Business Acquisition [Line Items]
Amount of contingent purchase consideration, the company could be required to pay	$ 20,000								$ 20,000
Contingent consideration, liability	$ 18,100								$ 18,100
HEICO Electronic [Member] | SST [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									SST Components, Inc. (“SST Components”)
Description of Acquired Entity									SST Components manufactures discrete semiconductor components, tests electronic components, and custom assembles a wide variety of prototype and off the shelf components into desired package styles for military, space and commercial uses.
Business Acquisition, Percentage of Voting Interests Acquired	53.10%								53.10%
HEICO Electronic [Member] | ELT [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Emergency Locator Transmitter Beacon
Description of Acquired Entity									The ELT Product Line designs and manufactures Emergency Locator Transmitter Beacons for the commercial aviation and defense markets that upon activation, transmit a distress signal to alert search and rescue operations of the aircraft's location.
HEICO Electronic [Member] | STE [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Sensor Technology Engineering, Inc. ("Sensor Technology")
Description of Acquired Entity									Sensor Technology designs and manufactures sophisticated nuclear radiation detectors for law enforcement, homeland security and military applications.
Business Acquisition, Percentage of Voting Interests Acquired	85.00%								85.00%
HEICO Electronic [Member] | IDC [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Interface Displays & Controls, Inc. ("IDC")
Description of Acquired Entity									IDC designs and manufactures electronic products for aviation, marine, military fighting vehicles, and embedded computing markets.
HEICO Electronic [Member] | Connect Tech [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Connect Tech Inc
Description of Acquired Entity									Connect Tech designs and manufacturers rugged, small-form-factor embedded computing solutions. Connect Tech's components are designed for very harsh environments and are primarily used in rugged commercial and industrial, aerospace and defense, transportation, and smart energy applications.
Amount of contingent purchase consideration, the company could be required to pay	$ 9,700								$ 9,700
Business Acquisition, Percentage of Voting Interests Acquired	89.99%								89.99%
HEICO Electronic [Member] | Transformational Security [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Transformational Security, LLC
HEICO Electronic [Member] | Intelligent Devices [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Intelligent Devices, Inc
HEICO Electronic [Member] | TSID [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Transformational Security, LLC and Intelligent Devices, Inc. (collectively, "TSID")
Description of Acquired Entity									TSID develops and manufactures state-of-the-art Technical Surveillance Countermeasures ("TSCM") equipment used to protect critical spaces from exploitation via wireless transmissions, technical surveillance and listening devices.
Amount of contingent purchase consideration, the company could be required to pay	$ 14,000								$ 14,000
Business Acquisition, Percentage of Voting Interests Acquired	75.00%								75.00%
Heico Flight Support Corp [Member] | FY2019 Acquisition [Member]
Business Acquisition [Line Items]
Amount of contingent purchase consideration, the company could be required to pay	$ 6,400								$ 6,400
Contingent consideration, liability					$ 1,100					$ 1,100
Heico Flight Support Corp [Member] | Decavo [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Decavo LLC
Description of Acquired Entity									Decavo designs and produces complex composite parts and assemblies incorporated into camera and related sensor assemblies and unmanned aerial vehicle ("UAV") airframes used in demanding defense and civilian applications.
Business Acquisition, Percentage of Voting Interests Acquired	80.10%								80.10%
Heico Flight Support Corp [Member] | ODE [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Optical Display Engineering ("ODE")
Description of Acquired Entity									ODE is a Federal Aviation Administration ("FAA")-authorized Part 145 Repair Station focusing on the repair of LCD screens and display modules for aviation displays used in civilian and military aircraft. ODE also holds FAA-Parts Manufacturer Approval authority to supply products that it repairs.
Heico Flight Support Corp [Member] | Rocky Mountain [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Rocky Mountain Hydrostatics, LLC
Description of Acquired Entity									Rocky Mountain overhauls industrial pumps, motors, and other hydraulic units with a focus on the support of legacy systems for the U.S. Navy.
Business Acquisition, Percentage of Voting Interests Acquired	70.00%								70.00%
Heico Flight Support Corp [Member] | Rocky Mountain [Member] | Existing Management [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	30.00%								30.00%
Electronic Technologies Group [Member] | EPC [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									EPC Space LLC
Description of Acquired Entity									EPC designs, develops, promotes, markets and sells radiation-hardened gallium nitride power solutions packaged for use in outer space and other high reliability applications.
Business Acquisition, Percentage of Voting Interests Acquired	49.00%								49.00%
Electronic Technologies Group [Member] | HMI [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Human-Machine Interface
Description of Acquired Entity									HMI designs, manufactures, and repairs flight deck annunciators, panels, indicators, and illuminated keyboards, as well as lighting controls, and flight deck lighting.
Business Acquisition, Percentage of Voting Interests Acquired	100.00%								100.00%
Electronic Technologies Group [Member] | Quell [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Quell Corporation
Description of Acquired Entity									Quell designs and manufactures electromagnetic interference (EMI)/radio-frequency interference (RFI) and transient protection solutions for a wide variety of connectors that principally serve customers within the aerospace and defense markets.
Business Acquisition, Percentage of Voting Interests Acquired	80.10%								80.10%
Flight Support Corp [Member] | Freebird [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	100.00%								100.00%