SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Allowance for doubtful accounts

Our allowance for doubtful accounts changed during the fiscal year ended September 30, 2020 and 2019 as follows:

	2020		2019
Beginning Balance	$	2,377	$	1,900
Amount of charge (benefit) to expense	(1,122)		432
Deductions and adjustments	(672)		45
Ending Balance at September 30	$	583	$	2,377

Customers who represent more than 10% of revenue

Customers who represented more than 10% of consolidated revenue, all of which are in the Electronic Materials segment, are as follows:

	Year Ended September 30,
	2020		2019		2018
Intel	15	%	14	%	*
Samsung Group (Samsung)	11	%	11	%	18	%
Taiwan Semiconductor Manufacturing Co. (TSMC)	*		*		12	%
SK Hynix Inc.	*		*		10	%

* Customer did not represent more than 10% of consolidated revenue.

Of those customers who represented more than 10% of consolidated revenue, their net accounts receivable as a percentage of total net accounts receivable are as follows:

	September 30,
	2020		2019
Intel	8.5	%	8.1	%
Samsung Group (Samsung)	7.0	%	5.5	%

Schedule of property, plant and equipment

Property, plant and equipment are recorded at cost. Depreciation is based on the following estimated useful lives of the assets using the straight-line method:

Land Improvements	10-20 years
Buildings	15-30 years
Machinery and equipment	3-20 years
Furniture and fixtures	5-10 years
Vehicles	5-8 years
Information systems	3-5 years
Assets under financing leases	The shorter of the term of the lease or estimated useful life