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, 2017			$ 338	$ 507	$ 326,544	$ 3,118	$ (3,118)	$ (10,556)	$ 844,247	$ 87,212	$ 1,248,292
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 80,125							14,973	65,152
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	7,537	$ 3,952								3,585
Comprehensive income	87,662										83,710
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					980						980
Share-based compensation expense					2,165						2,165
Proceeds from stock option exercises				1							1,425
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital					1,424
Distributions to noncontrolling interests		(1,688)								(194)	(194)
Adjustments to redemption amount of redeemable noncontrolling interests		(2,026)							2,026		2,026
Other										(1)	(995)
Adjustments to Additional Paid in Capital, Other					(994)
Ending Balance at Jan. 31, 2018			422	635	329,908	3,118	(3,118)	4,417	904,030	90,602	1,330,014
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	7,537	3,952								3,585
Distributions to noncontrolling interests		(1,688)								(194)	(194)
Adjustments to redemption amount of redeemable noncontrolling interests		(2,026)							2,026		2,026
Temporary Equity, Other Changes		994
Ending Balance, Redeemable Noncontrolling Interests at Jan. 31, 2018		132,355
Starting Balance at Oct. 31, 2018	1,503,008		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]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	83,519							4,187	79,332
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	8,887	3,639								5,248
Comprehensive income	92,406										88,767
Cash dividends									(9,305)		(9,305)
Issuance of common stock to Savings and Investment Plan					1,046						1,046
Share-based compensation expense					2,439						2,439
Proceeds from stock option exercises											66
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital					66
Stock Redeemed or Called During Period, Value					(150)						(150)
Noncontrolling Interest, Increase from Business Combination		5,116								2,355	2,355
Distributions to noncontrolling interests		(2,397)								(398)	(398)
Adjustments to redemption amount of redeemable noncontrolling interests		(228)							228		228
Deferred compensation obligation							(115)
Stock Issued During Period Value Deferred Compensation Obligation						115
Ending Balance at Jan. 31, 2019	1,601,755		$ 534	$ 796	$ 324,395	$ 4,043	$ (4,043)	$ (11,069)	1,174,811	112,288	1,601,755
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2018	132,046	132,046
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	8,887	3,639								5,248
Noncontrolling Interest, Increase from Business Combination		5,116								2,355	2,355
Distributions to noncontrolling interests		(2,397)								(398)	(398)
Adjustments to redemption amount of redeemable noncontrolling interests		(228)							228		228
Ending Balance, Redeemable Noncontrolling Interests at Jan. 31, 2019	$ 138,995	138,995
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2014-09 [Member]		819							13,373	326	13,699
Increase (Decrease) in Temporary Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2014-09 [Member]		$ 819							$ 13,373	$ 326	$ 13,699