QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Net sales:
Net sales	$ 476,884	$ 465,825	$ 430,602	$ 404,410	$ 421,224	$ 391,500	$ 368,657	$ 343,432	$ 1,777,721	$ 1,524,813	$ 1,376,258
Gross profit:
Gross profit	186,458	181,609	167,857	154,791	160,029	148,897	140,382	125,417
Net income from consolidated operations:
Net income from consolidated operations	74,081	73,899	66,011	71,695	59,087	51,475	50,833	46,265	285,686	207,660	176,150
Net income attributable to HEICO:
Net income attributable to HEICO	$ 67,377	$ 67,086	$ 59,618	$ 65,152	$ 53,674	$ 45,698	$ 45,686	$ 40,927	$ 259,233	$ 185,985	$ 156,192
Basic:
Basic (in dollars per share)	$ 0.51	$ 0.51	$ 0.45	$ 0.49	$ 0.41	$ 0.35	$ 0.35	$ 0.31	$ 1.96	$ 1.41	$ 1.19
Diluted:
Diluted (in dollars per share)	$ 0.49	$ 0.49	$ 0.44	$ 0.48	$ 0.39	$ 0.34	$ 0.34	$ 0.30	$ 1.90	$ 1.37	$ 1.17