Receivables

12 Months Ended

Sep. 30, 2017

Receivables [Abstract]

Receivables

Receivables

Receivables at September 30, 2017 and 2016 consisted of the following:

	September 30,
	2017			2016
	(In thousands)
Billed	$	126,887		$	124,731
Unbilled (1)	44,640			45,247
	171,527			169,978
Less: allowance for doubtful accounts	(2,941		)	(2,192		)
Receivables, net	$	168,586		$	167,786

(1) Represents revenue recorded in excess of amounts billable pursuant to contract provisions and generally become billable at contractually specified dates or upon the attainment of milestones. Unbilled amounts are expected to be realized within one year.

Activity in the allowance for doubtful accounts was as follows:

	Year Ended September 30,
	2017			2016
	(In thousands)
Balance, beginning of year	$	2,192		$	2,126
Add: expense	1,640			2,011
Less: write-offs (net of recoveries)	(891		)	(1,945		)
Balance, end of year	$	2,941		$	2,192