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	800	310,201	4,043	(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	$ 160,018								(1,096)	161,114
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	16,841	$ 8,224										8,617
Comprehensive income	176,859													168,635
Cash dividends										(9,305)				(9,305)
Issuance of common stock to Savings and Investment Plan						6,390								6,390
Share-based compensation expense						4,987								4,987
Proceeds from stock option exercises				7	4									5,528
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						5,517
Stock Redeemed or Called During Period, Value				(3)		(27,741)								(27,744)
Noncontrolling Interest, Increase from Business Combination		13,079										2,382		2,382
Distributions to noncontrolling interests		(7,384)										(806)		(806)
Adjustments to redemption amount of redeemable noncontrolling interests		4,666								(4,666)				(4,666)
Deferred compensation obligation							(115)
Stock Issued During Period Value Deferred Compensation Obligation								115
Stockholders' Equity, Other												2		56
Adjustments to Additional Paid in Capital, Other						54
Ending Balance at Apr. 30, 2019				538	800	310,201	4,043	(4,043)	(16,352)	1,251,699		115,278		1,662,164
Ending Balance (Accounting Standards Update 2014-09 [Member]) at Apr. 30, 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	16,841	8,224										8,617
Noncontrolling Interest, Increase from Business Combination		13,079										2,382		2,382
Distributions to noncontrolling interests		(7,384)										(806)		(806)
Adjustments to redemption amount of redeemable noncontrolling interests		4,666								(4,666)				(4,666)
Ending Balance, Redeemable Noncontrolling Interests at Apr. 30, 2019		151,450
Ending Balance, Redeemable Noncontrolling Interests (Accounting Standards Update 2014-09 [Member]) at Apr. 30, 2019			$ 819
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				534	796	324,395	4,043	(4,043)	(11,069)	1,174,811		112,288		1,601,755
Beginning Balance at Jan. 31, 2019				534	796	324,395	4,043	(4,043)	(11,069)	1,174,811		112,288		1,601,755
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				538	796	310,201	4,043	(4,043)	(11,069)	1,251,699		112,288		1,601,755
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	76,499								(5,283)	81,782
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	7,954	4,585										3,369
Comprehensive income	84,453													79,868
Issuance of common stock to Savings and Investment Plan						5,344								5,344
Share-based compensation expense						2,548								2,548
Proceeds from stock option exercises				7	4									5,462
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						5,451
Stock Redeemed or Called During Period, Value				(3)		(27,591)								(27,594)
Noncontrolling Interest, Increase from Business Combination		7,963										27		27
Distributions to noncontrolling interests		(4,987)										(408)		(408)
Adjustments to redemption amount of redeemable noncontrolling interests		4,894								(4,894)				(4,894)
Stockholders' Equity, Other												2		56
Adjustments to Additional Paid in Capital, Other						54
Ending Balance at Apr. 30, 2019				538	800	310,201	4,043	(4,043)	(16,352)	1,251,699		115,278		1,662,164
Ending Balance (Accounting Standards Update 2014-09 [Member]) at Apr. 30, 2019											13,373		326		13,699
Starting Balance, Redeemable Noncontrolling Interests at Jan. 31, 2019		138,995
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	7,954	4,585										3,369
Noncontrolling Interest, Increase from Business Combination		7,963										27		27
Distributions to noncontrolling interests		(4,987)										(408)		(408)
Adjustments to redemption amount of redeemable noncontrolling interests		4,894								(4,894)				(4,894)
Ending Balance, Redeemable Noncontrolling Interests at Apr. 30, 2019		151,450
Ending Balance, Redeemable Noncontrolling Interests (Accounting Standards Update 2014-09 [Member]) at Apr. 30, 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
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	806	297,324	4,232	(4,232)	(23,804)	1,583,646		31,006		1,889,520
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	190,276								(7,065)	197,341
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	13,075	9,422										3,653
Comprehensive income	203,351													193,929
Cash dividends										(10,762)				(10,762)
Issuance of common stock to Savings and Investment Plan						7,281								7,281
Share-based compensation expense						5,275								5,275
Proceeds from stock option exercises					2									2,392
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						2,390
Stock Redeemed or Called During Period, Value						(2,567)								(2,567)
Noncontrolling Interest, Increase from Business Combination		7,538
Distributions to noncontrolling interests		(8,977)										(765)		(765)
Adjustments to redemption amount of redeemable noncontrolling interests		260								(260)				(260)
Stockholders' Equity, Other				1										337
Adjustments to Additional Paid in Capital, Other						336
Ending Balance at Apr. 30, 2020	1,889,520			542	806	297,324	4,232	(4,232)	(23,804)	1,583,646		31,006		1,889,520
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	13,075	9,422										3,653
Noncontrolling Interest, Increase from Business Combination		7,538
Distributions to noncontrolling interests		(8,977)										(765)		(765)
Adjustments to redemption amount of redeemable noncontrolling interests		260								(260)				(260)
Ending Balance, Redeemable Noncontrolling Interests at Apr. 30, 2020	196,507	196,507
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				541	805	287,779	4,232	(4,232)	(19,263)	1,508,784		30,601		1,809,247
Beginning Balance at Jan. 31, 2020				541	805	287,779	4,232	(4,232)	(19,263)	1,508,784		30,601		1,809,247
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,889,520			541	806	287,779	4,232	(4,232)	(23,804)	1,508,784		31,006		1,889,520
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	70,912								(4,541)	75,453
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	5,291	4,655										636
Comprehensive income	76,203													71,548
Issuance of common stock to Savings and Investment Plan						5,983								5,983
Share-based compensation expense						2,629								2,629
Proceeds from stock option exercises					1									864
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital						863
Stock Redeemed or Called During Period, Value						(5)								(5)
Noncontrolling Interest, Increase from Business Combination		(2)
Distributions to noncontrolling interests		(4,630)										(231)		(231)
Adjustments to redemption amount of redeemable noncontrolling interests		591								(591)				(591)
Stockholders' Equity, Other				1										76
Adjustments to Additional Paid in Capital, Other						75
Ending Balance at Apr. 30, 2020	1,889,520			542	806	297,324	4,232	(4,232)	(23,804)	1,583,646		31,006		1,889,520
Starting Balance, Redeemable Noncontrolling Interests at Jan. 31, 2020		195,893
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	5,291	4,655										636
Noncontrolling Interest, Increase from Business Combination		(2)
Distributions to noncontrolling interests		(4,630)										(231)		(231)
Adjustments to redemption amount of redeemable noncontrolling interests		591								(591)				(591)
Ending Balance, Redeemable Noncontrolling Interests at Apr. 30, 2020	196,507	$ 196,507
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,889,520			$ 542	$ 806	$ 297,324	$ 4,232	$ (4,232)	$ (23,804)	$ 1,583,646		$ 31,006		$ 1,889,520