ACQUISITIONS (Details Textuals) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Business Acquisition [Line Items]
Net sales	$ 541,529	$ 532,324	$ 515,648	$ 466,146	$ 476,884	$ 465,825	$ 430,602	$ 404,410	$ 2,055,647	$ 1,777,721	$ 1,524,813
Net income	85,684	$ 81,098	$ 81,782	$ 79,332	67,377	$ 67,086	$ 59,618	$ 65,152	327,896	259,233	185,985
Acquisition Costs	3,200								3,200
Payments to Acquire Businesses, Net of Cash Acquired									240,841	59,775	418,265
Contingent consideration, liability	$ 18,326				$ 20,875				$ 18,326	20,875
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]
Pro Forma Revenue										$ 1,879,700
LLP Enterprises [Member] | A2C [Member]
Business Acquisition [Line Items]
Percentage of interest owned by noncontrolling shareholders	19.90%								19.90%
AAT [Member]
Business Acquisition [Line Items]
Amount of contingent purchase consideration, the company could be required to pay	$ 13,800								$ 13,800
Net sales											10,200
Net income											2,500
AAT [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									15 years
AAT [Member] | Intellectual Property [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life									15 years
Decavo [Member]
Business Acquisition [Line Items]
Amount of contingent purchase consideration, the company could be required to pay	$ 2,100								$ 2,100
FY 2017 Acquisition [Member]
Business Acquisition [Line Items]
Net sales											49,000
HEICO Electronic [Member] | AAT [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Sep. 15, 2017
Name of Acquired Entity									AeroAntenna Technology, Inc.
Description of Acquired Entity									AAT designs and produces high performance active antenna systems for commercial aircraft, precision guided munitions, other defense applications and commercial uses.
Payments to Acquire Businesses, Net of Cash Acquired									$ 316,632
Cash Acquired from Acquisition									$ 868
Pro Forma Revenue											$ 1,582,653
HEICO Electronic [Member] | TTT-Cubed [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Sep. 30, 2019
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]
Effective Date of Acquisition									Jul. 31, 2019
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.
Percentage of interest acquired in the subsidiary	70.00%								70.00%
HEICO Electronic [Member] | Research Electronics International [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Jun. 30, 2019
Name of Acquired Entity									Research Electronics International, LLC
Description of Acquired Entity									REI is a designer and manufacturer of Technical Surveillance Countermeasures (TSCM) equipment to detect devices used for espionage and information theft.
Percentage of interest acquired in the subsidiary	75.00%								75.00%
HEICO Electronic [Member] | Solid Sealing Technology [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Feb. 28, 2019
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.
Percentage of interest acquired in the subsidiary	85.00%								85.00%
HEICO Electronic [Member] | Freebird [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Nov. 30, 2018
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.
Percentage of interest acquired in the subsidiary	50.00%								50.00%
HEICO Electronic [Member] | Apex [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Nov. 30, 2018
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.
Percentage of interest acquired in the subsidiary	92.70%								92.70%
HEICO Electronic [Member] | Specialty Silicone Products [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Nov. 30, 2018
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] | SST [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Sep. 30, 2018
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.
Percentage of interest acquired in the subsidiary	53.10%								53.10%
HEICO Electronic [Member] | ELT [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Apr. 30, 2018
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]
Effective Date of Acquisition									Feb. 28, 2018
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.
Percentage of interest acquired in the subsidiary	85.00%								85.00%
HEICO Electronic [Member] | IDC [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Nov. 30, 2017
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 Flight Support Corp [Member] | LLP Enterprises [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									LLP Enterprises, LLC
Heico Flight Support Corp [Member] | LLP Enterprises [Member] | A2C [Member]
Business Acquisition [Line Items]
Name of Acquired Entity									Air Cost Control
Description of Acquired Entity									A2C is a leading aviation electrical interconnect product distributor of items such as connectors, wire, cable, protection and fastening systems, in addition to distributing a wide range of electromechanical parts.
Heico Flight Support Corp [Member] | Decavo [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Feb. 28, 2019
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.
Percentage of interest acquired in the subsidiary	80.10%								80.10%
Heico Flight Support Corp [Member] | ODE [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Aug. 31, 2018
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] | CBD [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Jun. 30, 2017
Name of Acquired Entity									Carbon by Design
Description of Acquired Entity									CBD is a manufacturer of composite components for UAVs, rockets, spacecraft and other specialized applications.
Heico Flight Support Corp [Member] | A2C [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition									Apr. 30, 2017
Percentage of interest acquired in the subsidiary	80.10%								80.10%