Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0000814547 (http://www.sec.gov/CIK)

Receivables [Abstract]	Period [Axis]
	2015-10-01 - 2016-09-30
Receivables [Abstract]
Receivables	Receivables at September 30, 2016 and 2015 consisted of the following:     September 30,   2016   2015   (In thousands) Billed $ 124,731   $ 114,464 Unbilled (1) 45,247   46,435   169,978   160,899 Less: allowance for doubtful accounts (2,192 )   (2,126 ) Receivables, net $ 167,786   $ 158,773 (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 of Allowance for Doubtful Accounts	Activity in the allowance for doubtful accounts was as follows:     Year Ended September 30,   2016   2015   (In thousands) Balance, beginning of year $ 2,126   $ 2,927 Add: expense 2,011   — Less: write-offs (net of recoveries) (1,945 )   (801 ) Balance, end of year $ 2,192   $ 2,126