INCOME TAXES	9 Months Ended
	Jul. 31, 2021
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	INCOME TAXESThe Company's effective tax rate in the first nine months of fiscal 2021 was 13.3%, as compared to 3.5% in the first nine months of fiscal 2020. The Company recognized a discrete tax benefit from stock option exercises in both the first quarter of fiscal 2021 and 2020 of $13.5 million and $47.6 million, respectively. The tax benefit from stock option exercises in both periods was the result of strong appreciation in HEICO's stock price during the optionees' holding periods and the $34.1 million larger benefit recognized in the first quarter of fiscal 2020 was the result of more stock options exercised. Additionally, the effective tax rate in the first nine months of fiscal 2021 reflects the favorable impact of higher tax-exempt unrealized gains in the cash surrender values of life insurance policies related to the HEICO Corporation Leadership Compensation Plan. The Company's effective tax rate was 15.7% in the third quarter of fiscal 2021, as compared to 13.4% in the third quarter of fiscal 2020. The increase principally reflects the fact that the third quarter of fiscal 2020 reflected a larger deduction related to Foreign-Derived Intangible Income ("FDII") principally resulting from the final tax regulations issued during that quarter as part of the Tax Cuts and Jobs Act that was enacted in December 2017.