QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Net sales:
Net sales	$ 541,529	$ 532,324	$ 515,648	$ 466,146	$ 476,884	$ 465,825	$ 430,602	$ 404,410	$ 2,055,647	$ 1,777,721	$ 1,524,813
Gross profit:
Gross profit	209,385	212,831	209,387	182,237	186,458	181,609	167,857	154,791
Net income from consolidated operations:
Net income from consolidated operations	92,573	89,059	90,083	88,026	74,081	73,899	66,011	71,695	359,741	285,686	207,660
Net income attributable to HEICO:
Net income attributable to HEICO	$ 85,684	$ 81,098	$ 81,782	$ 79,332	$ 67,377	$ 67,086	$ 59,618	$ 65,152	$ 327,896	$ 259,233	$ 185,985
Basic:
Basic (in dollars per share)	$ 0.64	$ 0.61	$ 0.61	$ 0.60	$ 0.51	$ 0.51	$ 0.45	$ 0.49	$ 2.45	$ 1.96	$ 1.41
Diluted:
Diluted (in dollars per share)	$ 0.62	$ 0.59	$ 0.60	$ 0.58	$ 0.49	$ 0.49	$ 0.44	$ 0.48	$ 2.39	$ 1.90	$ 1.37