SHARE-BASED COMPENSATION, Options Outstanding and Exercisable (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Number Outstanding (in shares)	3,993	4,692	6,400	7,297
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 36.75	$ 33.73	$ 23.19	$ 18.58
Outstanding Weighted Average Contractual Life (in years)	5 years 2 months 12 days
Outstanding Aggregated Intrinsic Value (in dollars)	$ 246,186
Number Exercisable (in shares)	2,714
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 27.52
Exercisable Weighted Average Contractual Life (in years)	4 years 2 months 12 days
Exercisable Aggregate Intrinsic Value (in dollars)	$ 193,604
Heico Common Stock [Member]
Number Outstanding (in shares)	1,681
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 35.91
Outstanding Weighted Average Contractual Life (in years)	4 years 8 months 12 days
Outstanding Aggregated Intrinsic Value (in dollars)	$ 116,257
Number Exercisable (in shares)	1,256
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 27.46
Exercisable Weighted Average Contractual Life (in years)	4 years
Exercisable Aggregate Intrinsic Value (in dollars)	$ 97,467
Common Class A [Member]
Number Outstanding (in shares)	2,312
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 37.36
Outstanding Weighted Average Contractual Life (in years)	5 years 6 months
Outstanding Aggregated Intrinsic Value (in dollars)	$ 129,929
Number Exercisable (in shares)	1,458
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 27.57
Exercisable Weighted Average Contractual Life (in years)	4 years 4 months 24 days
Exercisable Aggregate Intrinsic Value (in dollars)	$ 96,137