QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Net sales:
Net sales	$ 421,224	$ 391,500	$ 368,657	$ 343,432	$ 363,299	$ 356,084	$ 350,648	$ 306,227	$ 1,524,813	$ 1,376,258	$ 1,188,648
Gross profit:
Gross profit	160,029	148,897	140,382	125,417	135,684	133,583	134,029	112,196
Net income from consolidated operations:
Net income from consolidated operations	59,087	51,475	50,833	46,265	49,521	46,976	43,729	35,924	207,660	176,150	153,564
Net income attributable to HEICO:
Net income attributable to HEICO	$ 53,674	$ 45,698	$ 45,686	$ 40,927	$ 44,262	$ 42,002	$ 38,657	$ 31,271	$ 185,985	$ 156,192	$ 133,364
Basic:
Basic (in dollars per share)	$ 0.64	$ 0.54	$ 0.54	$ 0.49	$ 0.53	$ 0.50	$ 0.46	$ 0.37	$ 2.21	$ 1.86	$ 1.60
Diluted:
Diluted (in dollars per share)	$ 0.62	$ 0.53	$ 0.53	$ 0.47	$ 0.52	$ 0.49	$ 0.45	$ 0.37	$ 2.14	$ 1.83	$ 1.57