Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment
Balance (in shares) at Sep. 30, 2017			31,503,349
Balance at Sep. 30, 2017	$ 132,636	$ (107)	$ 29	$ 227,264	$ 100		$ (6,431)	$ (88,226)	$ (207)
Increase (Decrease) in Stockholders' Equity
Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units (in shares)			973,755
Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units	404		$ 1	403
Compensation expense and incremental tax benefit from grants of common stock options and restricted stock	6,346			6,346
Issuance of common stock for acquisition activity (in shares)			297,014
Issuance of common stock for acquisition activity	2,005		$ 3	2,002
Net loss	(11,615)							(11,615)
Defined benefit pension plan—unrecognized amounts, net of taxes	773						773
Foreign currency translation and other	(788)						(791)	3
Balance (in shares) at Sep. 30, 2018			32,774,118
Balance at Sep. 30, 2018	$ 129,654	$ 730	$ 33	236,115			(6,449)	(100,045)	$ 730
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201409Member
Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units (in shares)			953,066
Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units	$ 590		$ 1	589
Tax settlements associated with stock compensation expense (in shares)			(6,906)
Taxes paid associated with net settlement of stock compensation awards	(44)			(44)
Forfeiture of restricted stock awards (in shares)			(33,163)
Stock compensation expense	6,026			6,026
Net loss	(19,260)							(19,260)
Defined benefit pension plan—unrecognized amounts, net of taxes	(540)						(540)
Foreign currency translation and other	(981)						(984)	3
Balance (in shares) at Sep. 30, 2019			33,687,115
Balance at Sep. 30, 2019	116,175		$ 34	242,686			(7,973)	(118,572)
Increase (Decrease) in Stockholders' Equity
Common stock repurchases (in shares)						(547,508)
Common stock repurchases	(3,983)					$ (3,983)
Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units (in shares)			494,683
Exercise of common stock options, grants of restricted stock awards, and vesting of restricted stock units	111			111
Tax settlements associated with stock compensation expense (in shares)			(84,392)
Taxes paid associated with net settlement of stock compensation awards	(594)			(594)
Forfeiture of restricted stock awards (in shares)			(15,000)
Forfeiture of restricted stock awards	0
Stock compensation expense	5,689			5,689
Net loss	(3,774)							(3,774)
Defined benefit pension plan—unrecognized amounts, net of taxes	(2,293)						(2,293)
Foreign currency translation and other	484						484
Balance (in shares) at Sep. 30, 2020			34,082,406			547,508
Balance at Sep. 30, 2020	$ 111,815		$ 34	$ 247,892		$ 3,983	$ (9,782)	$ (122,346)
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member