SELECTED FINANCIAL STATEMENT INFORMATION (Details Textuals) - USD ($) $ in Millions	3 Months Ended
Jan. 31, 2018	Jan. 31, 2017	Oct. 31, 2017
Selected Financial Statement Information (Details) [Abstract]
Accrued customer rebates and credits	$ 14.2		$ 12.9
Total customer rebates and credits deducted within net sales	$ 2.5	$ 2.4

Carrying value as of the balance sheet date of accrued customer rebates and credits.

No definition available.

Name:	hei_AccruedCustomerRebatesAndCredits
Namespace Prefix:	hei_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant