Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 861	$ 1,199	$ 1,249
Charges (credits) to Expense	317	8	(34)
Deductions	(309)	(346)	(16)
Balance at End of Period	$ 869	$ 861	$ 1,199