Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 5,439	$ 5,371
Common stock, par value (in dollars per share)	$ 0.25	$ 0.25
Common stock, shares authorized (in shares)	64,000,000	64,000,000
Common stock, shares issued (in shares)	17,844,000	17,760,000
Common stock, shares outstanding (in shares)	17,844,000	17,760,000