SHARE-BASED COMPENSATION, Options Outstanding and Exercisable (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Number Outstanding (in shares)	4,692	6,400	7,297	6,520
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 33.73	$ 23.19	$ 18.58	$ 14.23
Outstanding Weighted Average Contractual Life (in years)	5 years 8 months 12 days
Outstanding Aggregated Intrinsic Value (in dollars)	$ 335,939
Number Exercisable (in shares)	2,785
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 21.57
Exercisable Weighted Average Contractual Life (in years)	4 years 2 months 12 days
Exercisable Aggregate Intrinsic Value (in dollars)	$ 234,156
Heico Common Stock [Member]
Number Outstanding (in shares)	1,682
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 35.91
Outstanding Weighted Average Contractual Life (in years)	5 years 7 months 6 days
Outstanding Aggregated Intrinsic Value (in dollars)	$ 147,012
Number Exercisable (in shares)	1,030
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 22.81
Exercisable Weighted Average Contractual Life (in years)	4 years 2 months 12 days
Exercisable Aggregate Intrinsic Value (in dollars)	$ 103,538
Common Class A [Member]
Number Outstanding (in shares)	3,010
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 32.52
Outstanding Weighted Average Contractual Life (in years)	5 years 9 months 18 days
Outstanding Aggregated Intrinsic Value (in dollars)	$ 188,927
Number Exercisable (in shares)	1,755
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 20.85
Exercisable Weighted Average Contractual Life (in years)	4 years 2 months 12 days
Exercisable Aggregate Intrinsic Value (in dollars)	$ 130,618