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, 2015			$ 269	$ 400	$ 286,220	$ 1,783	$ (1,783)	$ (25,080)	$ 548,054	$ 83,408	$ 893,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 114,638							2,708	111,930
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	14,900	$ 7,431								7,469
Comprehensive income	129,538										122,107
Cash dividends									(10,724)		(10,724)
Issuance of common stock to Savings and Investment Plan			1	1	5,913						5,915
Share-based compensation expense					4,905						4,905
Proceeds from stock option exercises				2							4,831
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital					4,829
Tax benefit from stock option exercises					867						867
Distributions to noncontrolling interests		(7,337)								(8,819)	(8,819)
Adjustments to redemption amount of redeemable noncontrolling interests		129							(129)		(129)
Deferred compensation obligation						(148)
Stock Issued During Period Value Deferred Compensation Obligation							148
Other										50	46
Adjustments to Additional Paid in Capital, Other					(4)
Ending Balance at Jul. 31, 2016			270	403	302,730	1,635	(1,635)	(22,372)	649,131	82,108	1,012,270
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2015		91,282
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	14,900	7,431								7,469
Distributions to noncontrolling interests		(7,337)								(8,819)	(8,819)
Acquisition of noncontrolling interests		(3,599)
Adjustments to redemption amount of redeemable noncontrolling interests		129							(129)		(129)
Ending Balance, Redeemable Noncontrolling Interests at Jul. 31, 2016		87,906
Starting Balance at Oct. 31, 2016	1,047,705		270	403	306,328	2,460	(2,460)	(25,326)	681,704	84,326	1,047,705
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	149,070							16,759	132,311
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	17,379	9,127								8,252
Comprehensive income	166,449										157,322
Cash dividends									(12,807)		(12,807)
Stock Issued During Period, Value, Stock Dividend			68	101
Adjustments to Additional Paid in Capital, Stock Split					(169)
Dividends, Common Stock, Stock									(23)		(23)
Issuance of common stock to Savings and Investment Plan					6,489						6,489
Share-based compensation expense					5,207						5,207
Proceeds from stock option exercises				2							4,171
Proceeds from stock option exercises, Adjustment to Additional Paid in Capital					4,169
Distributions to noncontrolling interests		(5,093)								(7,831)	(7,831)
Adjustments to redemption amount of redeemable noncontrolling interests		3,565							(3,565)		(3,565)
Deferred compensation obligation						(140)
Stock Issued During Period Value Deferred Compensation Obligation							140
Other									(1)		(1)
Ending Balance at Jul. 31, 2017	1,196,669		$ 338	$ 506	$ 322,024	$ 2,320	$ (2,320)	$ (8,567)	797,621	84,747	1,196,669
Starting Balance, Redeemable Noncontrolling Interests at Oct. 31, 2016	99,512	99,512
Increase (Decrease) in Temporary Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	17,379	9,127								8,252
Noncontrolling Interest, Increase from Business Combination		23,618
Distributions to noncontrolling interests		(5,093)								$ (7,831)	(7,831)
Acquisition of noncontrolling interests		(3,848)
Adjustments to redemption amount of redeemable noncontrolling interests		3,565							$ (3,565)		$ (3,565)
Ending Balance, Redeemable Noncontrolling Interests at Jul. 31, 2017	$ 126,881	$ 126,881