CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - UNAUDITED - USD ($) $ in Thousands	9 Months Ended
	Jul. 31, 2023	Jul. 31, 2022
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income from consolidated operations	$ 330,818	$ 280,450
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation, Depletion and Amortization	86,315	70,526
Employer contributions to HEICO Savings and Investment Plan	10,647	8,884
Stock or Unit Option Plan Expense	10,412	9,815
Change in value of contingent consideration	1,218	(4,253)
Business Combination, Reversal of Remaining Contingent Consideration, Liability	(9,057)	0
Payment for Contingent Consideration Liability, Operating Activities	(6,299)	0
Deferred income tax provision (benefit)	(22,974)	7,858
Increase (Decrease) in Operating Capital [Abstract]
Increase (Decrease) in Receivables	(15,615)	(18,445)
Change in contract assets	(7,863)	(4,022)
Increase (Decrease) in Inventories	(86,681)	(61,190)
Increase (Decrease) in Prepaid Expense and Other Assets	1,302	(11,701)
Change in trade accounts payable	(1,685)	18,959
Change in accrued expenses and other current liabilities	12,164	12,963
Increase (Decrease) in Income Taxes Payable	(4,967)	(2,405)
Change in other long-term liabilities and assets related to HEICO Leadership Compensation Plan	11,734	13,735
Other Noncash Income (Expense)	(9,112)	2,736
Net cash provided by operating activities	300,357	323,910
Net Cash Provided by (Used in) Investing Activities [Abstract]
Payments to Acquire Businesses, Net of Cash Acquired	(526,702)	(175,298)
Payments to Acquire Property, Plant, and Equipment	(34,176)	(24,357)
Net Investment Related to Deferred Compensation Plan	(14,000)	(13,400)
Payments for (Proceeds from) Other Investing Activities	689	(10,296)
Net cash used in investing activities	(574,189)	(223,351)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from Issuance of Senior Long-Term Debt	1,189,452	0
Proceeds from Long-term Lines of Credit	564,000	162,000
Repayments of Long-Term Lines of Credit	(839,000)	(157,000)
Payments of Ordinary Dividends, Noncontrolling Interest	(29,934)	(16,766)
Payments of Ordinary Dividends, Common Stock	(27,370)	(24,466)
Common Stock Issued Repurchased and Retired Related To Stock Option Exercises	(14,847)	(25,826)
Payment for Contingent Consideration Liability, Financing Activities	(12,610)	0
Payments of Debt Issuance Costs	(9,055)	(1,010)
Payments to Noncontrolling Interests	(2,733)	(8,735)
Proceeds from Stock Options Exercised	5,484	1,870
Proceeds from (Payments for) Other Financing Activities	694	(157)
Net cash (used in) provided by financing activities	824,081	(70,090)
Effect of exchange rate changes on cash	4,510	(5,162)
Net (decrease) increase in cash and cash equivalents	554,759	25,307
Cash and cash equivalents at beginning of year	139,504	108,298
Cash and cash equivalents at end of period	$ 694,263	$ 133,605