CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND COMPREHENSIVE INCOME - UNAUDITED - USD ($) $ in Thousands	Total	Redeemable Noncontrolling Interests [Member]	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]	Noncontrolling Interest [Member]	Total Shareholders Equity [Member]
Starting Balance at Oct. 31, 2016	$ 1,047,705		$ 270	$ 403	$ 306,328	$ 2,460	$ (2,460)	$ (25,326)	$ 681,704	$ 84,326
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	86,937							324	86,613
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	10,410	$ 5,151								5,259
Comprehensive income	97,347										$ 92,196
Cash dividends	(6,059)								(6,059)
Stock Issued During Period, Value, Stock Dividend			68	101
Adjustments to Additional Paid in Capital, Stock Split					(169)
Five-for-Four Common Stock Split	(23)								(23)
Issuance of common stock to Savings and Investment Plan	5,484				5,484
Share-based compensation expense	3,110				3,110
Proceeds from stock option exercises	2,297			1	2,296
Distributions to noncontrolling interests		(3,544)								(353)	(353)
Acquisition of noncontrolling interests		(3,848)
Adjustments to redemption amount of redeemable noncontrolling interests		5,826							(5,826)		(5,826)
Deferred compensation obligation						(140)
Stock Issued During Period Value Deferred Compensation Obligation							140
Other				(1)					1
Ending Balance at Apr. 30, 2017	1,138,531		338	506	317,049	2,320	(2,320)	(25,002)	756,408	89,232
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2016	99,512
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	10,410	5,151								5,259
Distributions to noncontrolling interests		(3,544)								(353)	(353)
Adjustments to redemption amount of redeemable noncontrolling interests		5,826							(5,826)		(5,826)
Noncontrolling interests assumed related to acquisition		22,035
Ending Balance, Redeemable Noncontrolling Interests at Apr. 30, 2017	125,132
Starting Balance at Oct. 31, 2017	1,248,292		338	507	326,544	3,118	(3,118)	(10,556)	844,247	87,212
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	133,589							8,819	124,770
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	13,513	6,636								6,877
Comprehensive income	147,102										140,466
Cash dividends	(7,395)								(7,395)
Stock Issued During Period, Value, Stock Dividend			84	127
Adjustments to Additional Paid in Capital, Stock Split					(211)
Issuance of common stock to Savings and Investment Plan	4,548		1		4,547
Share-based compensation expense	4,459				4,459
Proceeds from stock option exercises	1,993		7	1	1,985
Redemption of common stock related to share-based compensation	(24,623)		(3)		(24,620)
Distributions to noncontrolling interests		(4,040)								(409)	(409)
Adjustments to redemption amount of redeemable noncontrolling interests		(3,170)							3,170		3,170
Other								(221)	(221)
Adjustments to Additional Paid in Capital, Other	(994)				(994)
Ending Balance at Apr. 30, 2018	1,369,507		$ 427	$ 635	$ 311,710	$ 3,118	$ (3,118)	$ (1,516)	964,571	93,680
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2017	131,123
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	13,513	6,636								6,877
Distributions to noncontrolling interests		(4,040)								$ (409)	(409)
Adjustments to redemption amount of redeemable noncontrolling interests		$ (3,170)							$ 3,170		$ 3,170
Noncontrolling interests assumed related to acquisition	2,491
Other	994
Ending Balance, Redeemable Noncontrolling Interests at Apr. 30, 2018	$ 134,034