Annual report pursuant to Section 13 and 15(d)

Accounts receivable reserves

v3.10.0.1
Accounts receivable reserves
 12 Months Ended
Sep. 30, 2018
Receivables [Abstract]  
Accounts receivable reserves
Accounts receivable reserves
Changes in the reserves against accounts receivable were as follows (in thousands):
 
Year ended September 30,
 
2018
 
2017
 
2016
Balance at beginning of year
$
6,843

 
$
4,226

 
$
3,385

Additions to reserve
243

 
5,106

 
2,335

Deductions
(2,801
)
 
(2,489
)
 
(1,494
)
Balance at end of year
$
4,285

 
$
6,843

 
$
4,226


In evaluating the net realizable value of accounts receivable, we consider such factors as current economic trends, customer credit-worthiness, and changes in the customer payment terms and collection trends. Changes in the assumptions used in analyzing a specific account receivable may result in a reserve being recognized in the period in which the change occurs.
At September 30, 2018 and 2017, $13.4 million and $10.3 million of our unbilled receivables related to amounts pursuant to contractual retainage provisions. We anticipate that the majority of the fiscal 2018 balance will be billed and collected during fiscal year 2019.