CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND COMPREHENSIVE INCOME - UNAUDITED - USD ($) $ in Thousands	Total	Redeemable Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests [Member] Cumulative Effect, Period of Adoption, Adjustment	Common Stock [Member]	Common Stock [Member] Class A Common Stock [Member]	Capital In Excess Of Par Value [Member]	Deferred Compensation Obligation [Member]	HEICO Stock Held By Irrevocable Trust [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] Cumulative Effect, Period of Adoption, Adjustment	Total Shareholders Equity [Member]	Total Shareholders Equity [Member] Cumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				$ 534	$ 796	$ 320,994	$ 3,928	$ (3,928)	$ (15,256)	$ 1,091,183		$ 104,757		$ 1,503,008
Beginning Balance at Oct. 31, 2018				534	796	320,994	3,928	(3,928)	(15,256)	1,091,183		104,757		1,503,008
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				538	803	309,058	3,429	(3,429)	(16,783)	1,322,383		26,376		1,642,375
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | Accounting Standards Update 2014-09 [Member]											$ 13,373		$ 326		$ 13,699
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 240,685								(1,527)	242,212
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	24,707	$ 13,232										11,475
Comprehensive income	265,392													252,160
Cash dividends										(18,691)				(18,691)
Issuance of common stock to Savings and Investment Plan						7,656								7,656
Share-based compensation expense						7,674								7,674
Proceeds from stock option exercises				7	8									8,270
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						8,255
Stock Redeemed or Called During Period, Value				(3)	(1)	(35,596)								(35,600)
Distributions to noncontrolling interests		(12,134)										(92,565)		(92,565)
Noncontrolling Interest, Increase from Business Combination		38,696										2,382		2,382
Adjustments to redemption amount of redeemable noncontrolling interests		5,694								(5,694)				(5,694)
Deferred compensation obligation							(499)
Stock Issued During Period Value Deferred Compensation Obligation								499
Stockholders' Equity, Other												1		76
Adjustments to Additional Paid in Capital, Other						75
Ending Balance at Jul. 31, 2019				538	803	309,058	3,429	(3,429)	(16,783)	1,322,383		26,376		1,642,375
Ending Balance (Accounting Standards Update 2014-09 [Member]) at Jul. 31, 2019											13,373		326		13,699
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2018		132,046
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	24,707	13,232										11,475
Distributions to noncontrolling interests		(12,134)										(92,565)		(92,565)
Noncontrolling Interest, Increase from Business Combination		38,696										2,382		2,382
Adjustments to redemption amount of redeemable noncontrolling interests		5,694								(5,694)				(5,694)
Ending Balance, Redeemable Noncontrolling Interests at Jul. 31, 2019		178,353
Ending Balance, Redeemable Noncontrolling Interests (Accounting Standards Update 2014-09 [Member]) at Jul. 31, 2019			$ 819
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				538	800	310,201	4,043	(4,043)	(16,352)	1,251,699		115,278		1,662,164
Beginning Balance at Apr. 30, 2019				538	800	310,201	4,043	(4,043)	(16,352)	1,251,699		115,278		1,662,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				538	803	309,058	3,429	(4,043)	(16,352)	1,251,699		115,278		1,662,164
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | Accounting Standards Update 2014-09 [Member]											13,373		326		13,699
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	80,667								(431)	81,098
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	7,866	5,008										2,858
Comprehensive income	88,533													83,525
Cash dividends										(9,386)				(9,386)
Issuance of common stock to Savings and Investment Plan						1,266								1,266
Share-based compensation expense						2,687								2,687
Proceeds from stock option exercises					4									2,742
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						2,738
Stock Redeemed or Called During Period, Value					(1)	(7,855)								(7,856)
Distributions to noncontrolling interests		(4,750)										(91,759)		(91,759)
Noncontrolling Interest, Increase from Business Combination		25,617
Adjustments to redemption amount of redeemable noncontrolling interests		1,028								(1,028)				(1,028)
Deferred compensation obligation							(614)
Stock Issued During Period Value Deferred Compensation Obligation								614
Stockholders' Equity, Other												(1)		20
Adjustments to Additional Paid in Capital, Other						21
Ending Balance at Jul. 31, 2019				538	803	309,058	3,429	(3,429)	(16,783)	1,322,383		26,376		1,642,375
Ending Balance (Accounting Standards Update 2014-09 [Member]) at Jul. 31, 2019											13,373		326		13,699
Starting Balance, Redeemable Noncontrolling Interests at Apr. 30, 2019		151,450
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	7,866	5,008										2,858
Distributions to noncontrolling interests		(4,750)										(91,759)		(91,759)
Noncontrolling Interest, Increase from Business Combination		25,617
Adjustments to redemption amount of redeemable noncontrolling interests		1,028								(1,028)				(1,028)
Ending Balance, Redeemable Noncontrolling Interests at Jul. 31, 2019		178,353
Ending Balance, Redeemable Noncontrolling Interests (Accounting Standards Update 2014-09 [Member]) at Jul. 31, 2019			$ 819
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				538	803	309,058	3,429	(3,429)	(16,783)	1,322,383		26,376		1,642,375
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | Accounting Standards Update 2014-09 [Member]											$ 13,373		$ 326		$ 13,699
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,694,660			541	804	284,609	4,232	(4,232)	(16,739)	1,397,327		28,118		1,694,660
Beginning Balance at Oct. 31, 2019	1,694,660			541	804	284,609	4,232	(4,232)	(16,739)	1,397,327		28,118		1,694,660
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,694,660			542	807	301,532	4,232	(4,232)	(4,451)	1,623,285		30,497		1,952,212
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	263,945								12,288	251,657
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	17,124	12,556										4,568
Comprehensive income	281,069													268,513
Cash dividends										(21,552)				(21,552)
Issuance of common stock to Savings and Investment Plan				1		8,575								8,576
Share-based compensation expense						7,775								7,775
Proceeds from stock option exercises					4									5,345
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						5,341
Stock Redeemed or Called During Period, Value					(1)	(5,329)								(5,330)
Distributions to noncontrolling interests		(11,240)										(947)		(947)
Noncontrolling Interest, Increase from Business Combination		16,471
Adjustments to redemption amount of redeemable noncontrolling interests		4,147								(4,147)				(4,147)
Stockholders' Equity, Other												(1,242)		(681)
Adjustments to Additional Paid in Capital, Other						561
Ending Balance at Jul. 31, 2020	1,952,212			542	807	301,532	4,232	(4,232)	(4,451)	1,623,285		30,497		1,952,212
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2019	188,264	188,264
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	17,124	12,556										4,568
Distributions to noncontrolling interests		(11,240)										(947)		(947)
Acquisitions of noncontrolling interests	(7,475)
Noncontrolling Interest, Increase from Business Combination		16,471
Adjustments to redemption amount of redeemable noncontrolling interests		4,147								(4,147)				(4,147)
Temporary Equity, Other Changes	1,416
Ending Balance, Redeemable Noncontrolling Interests at Jul. 31, 2020	204,139	204,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				542	806	297,324	4,232	(4,232)	(23,804)	1,583,646		31,006		1,889,520
Beginning Balance at Apr. 30, 2020				542	806	297,324	4,232	(4,232)	(23,804)	1,583,646		31,006		1,889,520
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,952,212			542	807	297,324	4,232	(4,232)	(23,804)	1,583,646		30,497		1,952,212
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	73,669								19,353	54,316
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	4,049	3,134										915
Comprehensive income	77,718													74,584
Cash dividends										(10,790)				(10,790)
Issuance of common stock to Savings and Investment Plan				1		1,294								1,295
Share-based compensation expense						2,500								2,500
Proceeds from stock option exercises					2									2,953
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						2,951
Stock Redeemed or Called During Period, Value					(1)	(2,762)								(2,763)
Distributions to noncontrolling interests		(2,263)										(182)		(182)
Noncontrolling Interest, Increase from Business Combination		8,933
Adjustments to redemption amount of redeemable noncontrolling interests		3,887								(3,887)				(3,887)
Stockholders' Equity, Other				(1)								(1,242)		(1,018)
Adjustments to Additional Paid in Capital, Other						225
Ending Balance at Jul. 31, 2020	1,952,212			542	807	301,532	4,232	(4,232)	(4,451)	1,623,285		30,497		1,952,212
Starting Balance, Redeemable Noncontrolling Interests at Apr. 30, 2020		196,507
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	4,049	3,134										915
Distributions to noncontrolling interests		(2,263)										(182)		(182)
Acquisitions of noncontrolling interests	(7,475)
Noncontrolling Interest, Increase from Business Combination		8,933
Adjustments to redemption amount of redeemable noncontrolling interests		3,887								(3,887)				(3,887)
Temporary Equity, Other Changes	1,416
Ending Balance, Redeemable Noncontrolling Interests at Jul. 31, 2020	204,139	$ 204,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,952,212			$ 542	$ 807	$ 301,532	$ 4,232	$ (4,232)	$ (4,451)	$ 1,623,285		$ 30,497		$ 1,952,212